What is high speed steel

Steel P18 - decoding of high-speed alloy markings, characteristics and application

Alloy P18 belongs to the category of tool high-speed steels. P18 calibrated rods are also called silver bars. Characterized by a vanadium content of less than 2%. Can be processed well by welding and grinding.

The material is used for the manufacture of tools for metal-cutting machines: cutters, drills, cutters, broaches, shaver, cutters and others.

High performance characteristics of the tool are provided by carbide-forming elements introduced into the alloy as alloying elements.

Tools that work with high performance and resistance are made from high-speed steel. At the same time, they retain their cutting properties when heated to 700 °C.

P18, interpretation of steel markings

The designation of the alloy grade is clear to the enlightened. It is deciphered as follows:

• R - high-speed steel;
• 18 - tungsten content.

In addition to tungsten, the alloy also contains:

• Fe (iron) - 73%;
• Cr (chrome) - 4%;
• V (vanadium) - no more than 1.4%;
• Mo (molybdenum) - less than 1%;
• C (carbon) - 0.8%
• Si (silicon) - 0.5%;
• Mn (manganese) - 0.5%;
• Co (cobalt) - 0.5%;
• Ni (nickel) - 0.4%;
• S (sulfur) - 0.03%;
• P (phosphorus) - 0.03%.

Characteristics and Application

Speaking about p18 steel, characteristics and application, it should be noted that the tools made from it after heat treatment have a hardness of HRC 6265 units and high strength. This is quite enough for processing structural steels of ordinary quality. Long-term red resistance without loss of strength allows for long-term processing of parts.

But the big disadvantage of the alloy is carbide heterogeneity. This is especially noticeable in large-diameter workpieces. In large tools, this disadvantage manifests itself as a decrease in durability and chipping of cutting elements.

The problem is solved by increasing the excess amount of carbide phase. Heat treatment makes the internal structure of the steel fine-grained.

Material properties

P18 steel has the following physical properties

Parameter	Unit
Density,	8800 kg/cm3
Modulus of elasticity, E	220 GPa
Torsional shear modulus, G	83 GPa
Thermal conductivity	28 W/(m degrees)

Electrical resistivity depends on the heating temperature of the metal

Electrical resistivity
Temperature, degrees	Quantity
20	420
100	470
200	545
300	630
400	720
500	815
600	920
700	1035
800	1150
900	1175

Mechanical properties are isolated from the manufacturer’s plant and after heat treatment

From the manufacturer

Tensile strength, Ϭ B	830 MPa
Maximum fluidity, Ϭ T	450 MPa
Linear elongation, δ 5	13%
Restriction limit, ψ	22%
Ultimate compressive strength, Ϭ SJ	1050 MPa
Hardness, HB	227
Impact strength, KCU	100 kJ/m2

After heat treatment

Parameter	Value, MPa
Ϭ V	2150
Ϭ T	2480
Ϭ SJ0.2	3060
Ϭ SJ	3820
Ϭ IZG	3000
Tk	1880

Heat resistance (red resistance). At 610 °C the hardness is HRC 59 for 4 hours .

Technological properties

Forging temperature	900 °C - 1200 °C
Cooling after forging	750 °C - 800 °C, well
Weldability	Good, no restrictions
Machining	HB up to 228, K v = 0.3−0.6
Grinding processing	Increased
Flock sensitivity	Negative

The use of high-speed steel P18 is typical for cutting blade tools that are designed for processing metals of varying hardness, including stainless and heat-resistant steels.

Their hardness reaches HRC 70. They are characterized by increased resistance to plastic deformation and wear resistance when heated. Unlike tool steels, P18 tools increase the processing speed up to 4 times.

Improved performance properties are achieved by heat treatment. Heating for hardening is carried out to a temperature of 1300 °C. Cobalt introduced into the composition increases the transformation temperature of the internal structure of carbides. Fe3W3C is considered the main carbide. When heated and held, a significant part of the carbide passes into a solid solution of martensite or austenite.

Low tempering is used to obtain a fine-grained internal structure. Conducting temperature 550 °C - 560 °C. In this phase, the decay of retained austenite and the precipitation of dispersed carbides occurs.

To prevent the formation of cracks, heating for hardening is carried out in stages. First heated to 500 °C, then to 850 °C. Exposure at a temperature of 1300 °C is carried out depending on the thickness of the workpiece. Time no more than 15 seconds per 1 mm of size with a diameter of no more than 30 mm. For example, the cutter diameter is 10 mm. The exposure time should not exceed 150 seconds (2.5 minutes).

The heating time is twice as long as the holding time of the workpiece. Due to the excess amount of carbides, retained austenite cannot be completely transformed. Therefore, multiple holidays are used.

High-speed steel cutting tools undergo additional processing to increase the corrosion resistance and wear resistance of the cutting edge. Depending on the type of material being processed, the following is used:

• nitriding, which reduces the fragility of the surface layer;
• cyanidation, which increases viscosity;
• sulfidation;
• steaming.

These operations are carried out after heat treatment, sharpening and grinding. This helps give the finished tool greater strength.

Source: https://tokar.guru/metally/stal/bystrorezhuschaya-stal-r18-harakteristika-i-oblast-primeneniya.html

High-speed tool steels: grades, characteristics, markings

Materials such as high-speed steels have unique properties, which makes it possible to use them for the manufacture of tools with increased strength. The characteristics of steels classified as high-speed steels allow them to be used to produce tools for a wide variety of purposes.

Mills, taps, reamers are typical products made from high-quality high-speed steel

Characteristics of high-speed steels

The category of high-speed steels includes alloys whose chemical composition is supplemented with a number of alloying additives.

Thanks to such additives, steels are given properties that allow them to be used for the manufacture of cutting tools that can operate efficiently at high speeds.

What distinguishes high-speed tool steels from conventional carbon alloys is that the tools made from them can be successfully used for processing hard materials at high speeds.

Milling a part on a professional engraving machine

The most notable characteristics that distinguish high-speed steels of various grades include the following.

• Hardness maintained when hot (hot hardness). As is known, any tool used to perform cutting processing is intensely heated during such processing. As a result of heating, conventional tool steels are subjected to tempering, which ultimately leads to a decrease in the hardness of the tool. This does not happen if high-speed steel was used for manufacturing, which is capable of maintaining its hardness even when the tool is heated to 6000. Typically, high-speed steel grades, which are often called high-speed steels, have even lower hardness compared to conventional carbon steels if the cutting temperature is within normal limits: up to 2000.
• Increased red fastness. This parameter of any metal characterizes the period of time during which a tool made from it is able to withstand high temperatures without losing its original characteristics. High-speed steels as a material for the manufacture of cutting tools have no equal in this parameter.
• Resistance to destruction. A cutting tool, in addition to its ability to withstand exposure to elevated temperatures, must also have improved mechanical characteristics, which is fully demonstrated by high-speed steel grades. Tools made from such steels, which have high strength, can successfully operate at large depths of cut (drills) and at high feed rates (cutters, drills, etc.).

Characteristics and purpose of high-speed steels

Decoding the designation of steel grades

Initially, high-speed steel as a material for the manufacture of cutting tools was invented by British specialists.

Taking into account the fact that tools made from such steel can be used for high-speed processing of metals, this material was called “rapidsteel” (the word “rapid” here means high speed).

This property of these steels and the English name he invented at one time was the reason that the designations of all grades of this material begin with the letter “P”.

The rules for marking steels classified as high-speed steels are strictly regulated by the relevant GOST, which greatly simplifies the process of deciphering them.

The first number after the letter P in the designation of steel indicates the percentage content of such an element as tungsten, which largely determines the basic properties of this material.

In addition to tungsten, high-speed steel contains vanadium, molybdenum and cobalt, which are designated in the markings by the letters F, M and K, respectively.

After each such letter in the marking there is a number indicating the percentage of the corresponding element in the chemical composition of the steel.

An example of decoding a high-speed steel grade

Depending on the content of certain elements in the steel, as well as their quantity, all such alloys are divided into three main categories. It is quite easy to determine which category steel belongs to by deciphering its markings.

So, high-speed steel grades are usually divided into the following categories:

• alloys containing up to 10% cobalt and up to 22% tungsten; These steels include alloys of grades R6M5F2K8, R10M4F3K10, etc.;
• steel containing no more than 5% cobalt and up to 18% tungsten; such steels are alloys of grades R9K5, R18F2K5, R10F5K5, etc.;
• alloys that contain no more than 16% of both cobalt and tungsten; These alloys include steel R9, R18, R12, R6M5, etc.

Determining the type of steel by spark

As mentioned above, the characteristics of steels classified as high-speed steels are mainly determined by the content of such an element as tungsten.

It should be borne in mind that if a high-speed alloy contains too much tungsten, cobalt and vanadium, then due to the formation of carbide heterogeneity in such steel, the cutting edge of the tool that is made from it may chip under the influence of mechanical loads.

Tools made from steels containing molybdenum do not have such disadvantages. The cutting edge of such tools not only does not chip, but is also distinguished by the fact that it has the same hardness indicators along its entire length.

The grade of steel for the manufacture of tools, which are subject to increased requirements for their technological characteristics, is P18. Having a fine-grained internal structure, this steel exhibits excellent wear resistance.

Another advantage of using steel of this grade is that when hardening products made from it, they do not overheat, which cannot be said about high-speed alloys of other brands.

Due to the relatively high cost of tools made from steel of this grade, it is often replaced with the cheaper P9 alloy.

Technical characteristics of steel grade P18

The fairly low cost of steel grade P9, as well as its variety - P9K5, which in its characteristics is in many ways similar to the high-speed alloy P18, is explained by a number of disadvantages of this material. The most significant of them is that in the annealed state such a metal is easily susceptible to plastic deformation.

Meanwhile, P18 grade steel is also not without its drawbacks. Thus, high-precision tools are not made from this steel, which is explained by the fact that products made from it are difficult to grind.

Good indicators of strength and ductility, including in a heated state, are demonstrated by tools made from P12 steel, which in its characteristics is also similar to P18 steel.

Properties of steel grade R9K5

Production and Processing Methods

For the production of tools made from high-speed alloys, two main technologies are used:

• the classical method, which involves casting molten metal into ingots, which are then subjected to forging;
• a method of powder metallurgy in which molten metal is atomized using a stream of nitrogen.

Classic technology, which involves forging a product from a high-speed alloy that has previously been cast into a special mold, allows such a product to be endowed with higher quality characteristics.

This technology helps to avoid the formation of carbide segregations in the finished product, and also makes it possible to subject it to preliminary annealing and further hardening. In addition, this manufacturing technology avoids the phenomenon of “naphthalene fracture”, which leads to a significant increase in the fragility of the finished product made from a high-speed alloy.

Hardening of finished tools made of high-speed alloy is carried out at temperatures that promote better dissolution of alloying additives in them, but at the same time do not lead to grain growth in their internal structure.

After hardening, high-speed alloys have up to 30% austenite in their structure, which does not have the best effect on the thermal conductivity of the material and its hardness.

In order to reduce the amount of austenite in the alloy structure to minimum values, two technologies are used:

• carry out several cycles of heating the product, holding it at a certain temperature and cooling: multiple tempering;
• Before tempering, the product is cooled to a fairly low temperature: up to –800.

Improvement of product characteristics

In order for tools made from high-speed alloys to have high hardness, wear resistance and corrosion resistance, their surface must be subjected to processing, the methods of which include the following.

• Saturation of the surface layer of the product with nitrogen - nitriding. Such treatment can be carried out in a gas environment consisting of nitrogen (80%) and ammonia (20%), or completely in an ammonia environment. The time required to perform such a technological operation is 10–40 minutes, the temperature at which it is carried out is 550–6600. The use of a gas environment containing nitrogen and ammonia allows the formation of a less brittle surface layer.
• Saturation of the surface layer of a product with carbon and nitrogen is cyanidation, which is carried out in a melt of sodium cyanide or other salts with the same anion. Depending on the purpose of the part, cyanidation can be done at high, medium and low temperatures. The higher the temperature and exposure time of the part in the melt, the greater the thickness of the resulting layer.
• Sulfidation, which is performed in liquid sulfide melts to which sulfur compounds are added. This procedure is carried out for 45–180 minutes, and the melt temperature should be 450–5600.

Tools made from high-speed alloys are also subjected to steam treatment, which improves the characteristics of their surface layer. It should be borne in mind that all of the above operations are performed with a tool whose cutting part has already been sharpened, polished and heat treated.

Source: http://met-all.org/stal/bystrorezhushhaya-stal-instrumentalnaya-marki-harakteristiki-markirovka-bystrorez.html

Steel p18 - decoding of high-speed alloy markings, characteristics and application - Machine

18.12.2019

Steel grade P18 belongs to the high-speed class with normal performance.

It contains 18% tungsten, which provides improved technical qualities: increased hardness to HRC 62-65, red hardness to 600 degrees, and strength. It is very popular; knives and other cutting tools are often made from it.

The advantage of the products is the ease of machining, but the disadvantage is carbide heterogeneity, which worsens with increasing thickness of the part.

The main methods of steel processing are milling and sharpening; cutting, drilling, and tapping are also used. Processing of structural and alloy steel is carried out using a tool made of a stronger and harder metal, which can be P18 high-speed steel.

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Decoding

• The name contains information about the type of steel - high-speed tool steel (H), which contains 18% tungsten (18).
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Chemical composition

The metal contains:

• 73% ferrum;
• 17.75±0.75% tungsten;
• 15% molybdenum;
• 4.1±0.3% chromium;
• 1.2±0.2% vanadium;
• 0.78±0.05% carbon;
• 0.5% each of cobalt, manganese and silicon;
• 0.4% nickel;
• 0.03% each of sulfur and phosphorus.

Compliance of the composition of P18 steel with the specified standards ensures its strength, reliability and durability, allowing it to be used for the manufacture of tools and parts for turning and milling machines, cutting internal and external threads, creating and processing holes. The metal is suitable for machining alloyed, carbon, structural steel with a tensile strength of up to 1 GPa, and non-ferrous metals.

1. Maintaining operating parameters is ensured at temperatures below 600 C.
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Where is it used?

The metal is widely used in the creation of blade cutting tools intended for machining materials based on iron and carbon with varying degrees of hardness.

These include heat-resistant and stainless steels, the hardness of which reaches HRC70.

The use of P18 steel ensures an increase in processing speed, eliminates plastic deformation and changes in characteristics as a result of heating.

An increase in the technical parameters of the material is ensured by heat treatment. One of the methods is hardening, which is carried out at a temperature of 1300 degrees.

Due to the presence of cobalt in the composition, the temperature increases, at which the internal structure of carbides changes, the main one of which is Fe3W3C.

During quenching, most of this substance is converted to hard martensite or austenite.

Low tempering of high-speed steel P18 at t = 550-560 degrees makes it possible to obtain a fine-grained structure. This is due to the decomposition of the residual austenite form and the formation of dispersed carbide compounds.

Alternating heat treatment modes eliminates the risk of cracking. The order most often used is:

• heating up to 500 degrees;
• temperature increase up to 850 degrees;
• setting the temperature to 1300 degrees for a certain amount of time depending on the thickness of the element (1-30 mm, 15 seconds for each millimeter).

After this, stepwise tempering is carried out, which ensures a complete transformation of the residual austenitic structure of P18 steel.

Resistance to corrosion and wear is ensured by additional processing of the cutting part. To do this, one of the methods can be used:

• steaming;
• sulfide coating;
• cyanidation to increase viscosity;
• nitriding to reduce brittleness.

• They are carried out after heat treatment, sharpening and grinding, which guarantees increased strength.
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Specifications

The main characteristics of P18 steel are:

viscosity	100 kJ/m2;
Rockwell hardness	227;
compressive strength	10.5 GPa;
relative extension	13%;
yield strength	0.45 GPa;
tensile strength	0.83 GPa;
ability to conduct heat	28 W/mK;
shear/elastic modulus	83/220 GPa;
specific gravity	8.8 t/m3.

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Assortment

Products are produced in accordance with regulatory documents, which are GOST:

• No. 1133-71 – rolled elements;
• No. 4405-75 – strips and rods;
• TU 14-11-245-88 – profiles.

1. There are also other types of rentals.
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Cutting Application

Tool sharpening is 2-4 times faster when using P18 steel grade.

It is used for the manufacture of cutting tools used in difficult conditions, including heating and high loads.

This ensures that the basic technical characteristics of the products are preserved, which is an advantage. This parameter is necessary when creating automated workshops.

The high quality of the cut is due to the presence of alloying components in the material. Sharpening is carried out using emery wheels, but during the process it is important to eliminate dynamic and vibration effects.

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Production of cutting tools

The price of P18 steel is determined by the type of rolled product, taking into account the weight of the product and the volume of the order. One of the types of finished products is a drill, which is manufactured based on the requirements of State Standard 2034-80. These include the need to ensure a shank hardness of 63-68 HRC.

Grinding is the next stage after heat treatment. For this purpose, special machines are used that can guarantee compliance with the tolerances for the processed product - A1 and B1 according to h8, B - h9.

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Heat treatment

Quenching and tempering are the causes of dispersed solidification. In this case, the main part of the carbide compounds decomposes, and a solid solution of austenite and martensite is formed.

As a result, the metal is saturated with carbon and alloying components. Heat treatment of P18 steel includes quenching at a temperature of 1200-1300 degrees and tempering at 550-560 degrees.

This ensures the ultimate strength of the composition due to the release of carbide compounds and the decomposition of austenite.

Tools of complex geometric shape, with a thin blade, operated under variable loads, must be strong and tough.

To achieve this, heat treatment includes various modes and types of heating and tempering, which leads to the decomposition of carbides and strengthening of the austenitic form. This also has a positive effect on temperature resistance.

A thin blade with a cutting edge width of 3-5 mm is hardened at a temperature of 1250 degrees.

Grade P18 has a characteristic feature - with stepless heating after heat treatment, cracks and other defects may form on the surface.

To eliminate this negative factor, heating is carried out in stages: in the first stage the temperature rises to 500 degrees, in the second – 850 degrees, in the third – 1300 degrees. To determine the duration of hardening, it is necessary to take into account the thickness of the product.

Each millimeter of section requires about 10-15 seconds. During the first two stages, this duration can be doubled.

Preliminary and final heating is carried out in a salt bath filled with a mixture of barium chlorides (78%) and sodium (22%). The solution is deoxidized by introducing magnesium fluoride, which prevents the formation of an oxide film on the metal surface.

The release also occurs in stages, the duration of each stage is 1 hour, there are 3 stages in total.

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Analogs of steel P18

Analogues of P18 steel include:

• Russian P12;
• Chinese W18Cr4V;
• European 1.3355;
• German HS18-0-1;
• American T1.

For a long time, this material was used to make cutting tools. Its hardness is due to temperature treatment, which also ensures the strength of the metal. Its only disadvantage is carbide heterogeneity, which is clearly visible in large cross-section rods.

Look also at the brands:

• 17G1S;
• 12Х18Н10Т;
• 40X13;
• 40ХН;
• M390.

Healthy? Save it to your wall! Thank you for like!

Source: https://regionvtormet.ru/okrashivanie/stal-r18-rasshifrovka-markirovki-bystrorezhushhego-splava-harakteristiki-i-primenenie.html

High-speed steel: GOST, composition, hardness, heat treatment:

In order for the working surface of the tool to maintain the specified properties for a long time, it is necessary to use special alloys and steels for the manufacture of such elements. Today, cutting tool parts are made from hard alloys and tool grades of steel. For cutters, cutters, and chisels, high-speed steel is mainly used.

Basic requirements for alloys for cutting tools

Parts of this type work for a long time under conditions of friction and elevated temperatures. However, the working surface must retain its properties, have high wear resistance and hardness. At high speeds that the tool picks up during the cutting process, its edge, the part itself, and the chips heat up.

Therefore, the main characteristic that high-speed steel should have is heat resistance. For difficult-to-cut materials, powdered high-speed steels are used. They have higher cutting properties. The disadvantage of such alloys is the difficult processing of workpieces.

All necessary characteristics are achieved by introducing certain alloying elements and special heat treatment.

Steel marking

High-speed steel is marked with the letter P, which is placed in front. The main alloying elements are tungsten and chromium. Elements such as vanadium and molybdenum are also additionally introduced. The number after the letter P indicates the percentage of tungsten in the steel.

Typically, high-speed steel contains about 4% chromium. This element is not indicated in the labeling. If the numbers appear before the letter P, then they indicate the percentage of carbon (for example, steel 11Р3АМ3Ф2 contains 1.1% carbon).

Basically, the steels of this group are highly alloyed.

The influence of alloy elements on the properties of steel

High heat resistance of high-speed steel grades is provided by tungsten and molybdenum. On their basis, carbides are formed, which partially pass into solid solution. After heat treatment, the martensite structure is ensured. Tungsten, molybdenum, and vanadium slow down its decomposition. This is what provides the necessary red fastness. For a long time, high-speed steel alloyed only with tungsten was used.

However, due to the scarcity of this metal, they began to partially replace it with molybdenum. This element also has a positive effect on the tendency of tungsten steel grades to carbide heterogeneity. Vanadium forms the hardest carbide. However, the carbon content must be sufficient for greater saturation of the solid solution. The more vanadium is introduced, the more carbon there should be in the alloy.

The main task of chromium is to impart high hardenability to steel. Cobalt also increases red resistance.

High-speed steel (hardness when alloyed with this element increases to 70 HRC) in this case will have reduced strength. It is worth noting that the introduction of chromium is not widely used due to the high cost of the element.

Heat treatment of high speed steel

These steel grades are supplied in a forging state (temperature about 1200 °C). Heating is carried out to 860 °C, then the metal is maintained at a temperature of about 760 °C. Heat treatment of tools includes hardening and tempering. It is worth noting that such processing has its own characteristics. First, slow, gradual heating is necessary.

Since the steel is highly alloyed, its thermal conductivity is quite low, rapid heating can lead to the formation of cracks. It is very important to heat the workpiece evenly. Electric ovens and salt baths are used.

The process of processing high-speed steel is quite labor-intensive; it requires strict adherence to all stages of the technological process.

Hardening steel for cutting tools

The task of hardening is the dissolution of carbides in austenite. As a rule, tungsten and chromium-based carbides dissolve at 1200 °C; vanadium requires higher temperatures. After this stage, the structure has excess (those that have not dissolved) carbides. They inhibit grain growth.

High temperatures produce fine-grained austenite. Cooling occurs in oil or molten salts. The temperature across the cross section of the part is equalized. This treatment of high-speed steel avoids the appearance of cracks.

After hardening, the steel has the following structure: martensite, retained austenite, carbides.

Tempering of high speed steel

Tempering steel promotes the transformation of quenched martensite into tempered martensite, austenite into martensite (since the former does not have sufficient hardness), and the removal of residual stresses. Typically, heat treatment of high-speed steel involves repeated tempering. This process begins at a temperature of 150 °C. Next, at 550 °C, dispersion hardening occurs (carbides are released from the solid solution).

As a result, the hardness of the alloy increases. Higher tempering temperatures are undesirable, since the process of martensite decomposition will occur, and, accordingly, a decrease in hardness. Tungsten steels after a single tempering contain retained austenite. It completely turns into martensite during the second tempering. Residual stresses are removed during the third tempering process.

Steels containing cobalt can be tempered a fourth time.

Violation of heat treatment technology

A decrease in the amount of carbon on the surface of the workpiece may be a consequence of poor deoxidation of the salt bath, as well as overheating during austenitization. Exceeding the temperature leads to melting of the grain boundaries. Also, the processed part may have cracks.

This phenomenon occurs due to the rapid heating of the metal. Another reason is accelerated cooling. A low hardness value may be a consequence of insufficient alloying of the martensite structure, a violation of the temperature regime during tempering, at which retained austenite remains.

Another possible defect in the workpiece is mothball fracture.

The most common grades of high-speed steel

High-speed steel (GOST 19265-73) is divided into alloys of normal and increased heat resistance. The first group includes brands such as P18, P6M5. Their hardness reaches 63 HRC. Their main purpose is the processing of cast iron, copper, and aluminum alloys. Tungsten steels have higher heat resistance.

They are used for the manufacture of drills, cutters, and cutters. R6M5 steel, which contains molybdenum, is slightly inferior in cutting properties, but it is significantly cheaper. In addition, its ductility is somewhat higher, and its tendency to crack formation is not so high. More heat-resistant steels contain vanadium and cobalt (10Р6М5, Р9Ф5).

Their hardness reaches 66 HRC. They are used for processing stronger structural steels, heat-resistant alloys, and in the manufacture of finishing tools. It is characteristic that these brands have higher wear resistance (due to the presence of vanadium in the composition). Recently, the method of powder metallurgy has been increasingly used.

Such tools have higher cutting properties.

Source: https://www.syl.ru/article/208876/new_byistrorejuschaya-stal-gost-sostav-tverdost-termicheskaya-obrabotka

Steel quick cutter characteristics

R6M5 steel, sometimes called high-speed (high-speed) or self-cutting steel, belongs to the category of tool steels.

The presence of alloying elements in this steel, and the decoding P6M5, indicates that its mass volume contains about 6% tungsten and 5% molybdenum. By the way, the letter P shows that this steel is high-speed.

There are imported analogues - M2 (USA AISI/ASTM). The marking of imported steels begins with the abbreviation HSS, its decoding sounds like this - high-speed steel.

Normative base

Manufacturers of R6M5 steel must be guided by a number of GOSTs and TUs, which determine the range of products produced, the chemical composition, the procedure for control and acceptance of finished products. All steel that enters the domestic market from abroad must meet their requirements.

One of the fundamental documents is GOST 19265-73. It defines the basic requirements for this steel.

Characteristics of R6M5

Among the key properties of R6M5 are:

• propensity to decarbonize;

In addition, it can be processed well with grinding equipment.

All of the above characteristics allow it to be used in the production of tool products for a wide range of applications, which can be used to work with structural steels, including alloy steels.

Most often, P6M5 is used in the production of broaches, broaches, turning tools, milling cutters, etc.

Sometimes P6M5 is called tungsten-molybdenum steel. It is able to maintain its properties even when working at high temperatures. As an example, we can say that after heat treatment, its hardness remains unchanged.

The listed characteristics predetermined its use as a steel used for work at high temperatures.

Another quality of R6M5 steel is that it holds an edge well. In addition, this steel can withstand impact loads well. This allows its use as drills, reamers and other tool products.

Subtleties of heat treatment

Heat treatment of R6M5 has a number of technological subtleties. They are related to the decarburization properties of this steel and the time required to heat to the hardening temperature.

It is 1230 degrees Celsius and during the heating process they make a tempering when they reach 200 and 30 degrees; the time for these intermediate operations is one hour. Next, heating is stopped at 690, 860 and 1230 degrees.

The first two stops last three minutes, the last ninety seconds.

The rather complex hardening process cannot but affect the price of the alloy and the characteristics of the material.

Upon reaching the set temperature of 1230 degrees, R6M5 is cooled using nitrate, oil and air. After this, tempering is carried out at a temperature level of 560 degrees. The holding time is one and a half hours. At tempering points, alloying additives are added to the alloy, which give the product the necessary hardness.

Before starting all types of heat treatment, the steel must be annealed. This operation reduces fragility while maintaining its strength parameters.

Application of R6M5 in production and everyday life

P6M5 is often used for the production of knives, both in mass production and in everyday life. It should be noted that a properly sharpened knife can handle almost any material; on the Internet you can find a video where you can see how a knife made from this brand cuts a metal plate.

Despite the high price, knives made from P6M5 are very popular in everyday life, but the problem is that a product made from this steel is difficult to sharpen and therefore most often such a knife can be found among hunters, tourists, etc.

In almost every home you can find power tools, but all technological equipment and tools are made from P6M5.

Drills made from this steel are used for various jobs around the house. This alloy is used to produce products such as:

• simple drills, sharpened on one side;
• made in the form of a crown, they are intended for drywall;
• with a spear-shaped ending.

Of course, drills for working with metal are also made from this steel.

In industry, R6M5 is used for the manufacture of various tools, for example:

• blades for hand and mechanical hacksaws.

Sharpening features

Products made from R6M5 are subject to periodic dulling. We can immediately say that ordinary wheels made of electrocorundum are unlikely to help with sharpening. For this purpose, it is advisable to use abrasives made on the basis of CBN.

For sharpening and straightening, flat profile (PP) wheels, as well as cup wheels, are used. But sharpening with CBN-based wheels has its drawbacks, which are expressed in poor-quality surface cleanliness and the appearance of changes in the structure of the metal.

To achieve the maximum effect from sharpening the P6M5, it is recommended to sharpen in two passes:

• preliminary, for this purpose wheels with grain 40 are used;
• finishing, for this purpose use wheels with grain 25 - 16.

Price for steel R6M5

The cost of the R6M5 is quite high. So, in Moscow, a circle with a thickness of 2 mm costs 1,350 rubles per kilogram, and a circle with a thickness of 16 mm, its price will be 600 rubles per kilogram. For comparison, ordinary carbon steel costs between 20 and 40 rubles per kilogram.

It is the high cost of the high-speed cutter that encourages enterprises that use it in their work to collect its waste and hand it over to the appropriate organizations. Then, R6M5 is sent for remelting and a new tool is made.

A little history

R6M5 steel owes its origin to the next industrial revolution that took place in Britain. In the middle of the 19th century, the issue of processing steels and alloys became acute.

The cutting tool that existed at that time quickly heated up and the quality of processing was reduced to zero. As a result of research conducted by the English steelmaker R.

Mushshet tested steel containing in its chemical composition carbon, tungsten, manganese and other alloying additives.

Almost half a century later, American metallurgists created steel, which became the prototype of the modern P18 high-speed cutter. Around the same time, the R6M5 steel recipe was formed.

It must be said that the appearance of a quick cutter served as the basis for a significant increase in productivity in metalworking.

Source: https://varimtutru.com/stal-bystrorez-harakteristiki/

High-speed steel tools. Story. Essence. Prospects

 High speed steel tool

Changes in the relationship between temperature, exposure time and changes in the physical properties of tool alloy and high-speed steels.

steel grade	Temperature, °C	Exposure time, hour	Hardness, HRCе	Tools presented on our website
U7, U8, U10, U12	150—160	1	63
P9	580	4	Feather drill 90.0 P9 for metal (plate) GOST 25526-82
U7, U8, U10, U12	200—220	1	59
R6M5K5, R9, R9M4K8, R18	620—630	4	Three-sided cutter 63.0 x 4 x 22 R6M5K5 Z=24 with straight tooth

Percentage content of alloying chemical elements in high-speed steels

steel grade	C	Cr	W	Mo	V	Co	Tools presented on our website
Р0М2Ф3	1,10—1,25	3,8—4,6	—	2,3—2,9	2,6—3,3	—
R6M5	0,82—0,90	3,8—4,4	5,5—6,5	4,8—5,3	1,7—2,1	< 0,50	Three-sided cutter 63.0 x 5 x 22 Р6М5 Z=16 with straight tooth
R6M5F2K8	0,95—1,05	3,8—4,4	5,5—6,6	4,6—5,2	1,8—2,4	7,5—8,5
P9	0,85—0,95	3,8—4,4	8,5—10,0	< 1,0	2,0—2,6	—	Drill 7.4 x 80 x 170 P9 long
P18	0,73—0,83	3,8—4,4	17,0—18,5	< 1,0	1,0—1,4	< 0,50	Countersink 4.0 x 35 x 80 (H7) machine cylindrical flutes P18 Z=4 through

For a very long time, stones, wood and only a little metal were used to create household items, murder weapons and creative tools. Which is quite natural. Metal is difficult to process. Slowly, metallurgy and metalworking developed; lathes, milling and other machines were invented. There was a problem.

The industrial revolution was slowed down due to the catastrophically low cutting speed of metals.
The engines, even though they were bad. There were ways to transfer energy. But it is impossible to produce a sufficient number of high-precision metal products when the cutting speed was limited to 5 meters per minute. The situation began to change in the second half of the 19th century.

Then engineer R. Mushet, mixing some manganese, tungsten and carbon with ordinary steel, created a truly perfect, most technologically advanced alloy at that time, it was called “samokal”. He was the grandfather of today's high-speed cutters; 50 years later, the average cutting speed with the most advanced tools increased by 7!!! once.

Thanks to further progress, in the early 20s of the 20th century, up to 45 meters per minute and everything continues to accelerate.

In general terms outside and inside

High-speed steel was the perfect alloy of its time. It more than satisfied the needs of the industry, and partly exceeded expectations. The first full-fledged steel was P9. P comes from the English Rapid - speed.

Tungsten is available by default, which means there is no point in specifying it. tungsten - the number after R. High-speed steels contain chromium and molybdenum up to 5%. Tungsten can contain up to 18 hundredths parts. From 0.7 to 1.8 hundredths of carbon. And the most important metal here is cobalt.

But it is also the most expensive, so its content does not exceed 10%.

High-speed steel is produced by casting or powder metallurgy. The second method formed the basis for the production of hard alloys. When casting, in addition to the quality of the leaves, forging was of great importance. Or pressure treatment. High-quality annealing and tempering means even more. Many steels are tempered at temperatures ranging from -80 degrees to 900 degrees.

Quick cutter, why do they love him?

The most important advantage of high-speed steel tools is cutting speed. At the time of their appearance, the instruments were on the verge of fantasy and exceeded all expectations. At that time, the competitors of high-speed cutters were tool steels; their main problem was the complete lack of hot hardness. Here are three points of superiority of high-speed steel tools, for which they have gained popularity:

The most important property is red fastness. Determines how long a tool can experience high temperatures before its cutting edges start to look like cookies dropped in milk. For example, P18 in 4 hours at a temperature of 620 degrees will reduce the strength to 59 HRC. The most popular tool steels: U10, U12 120 will withstand heating of 150-200, their hardness does not drop significantly, to HRC63. A further increase in temperatures is simply critical and absolutely unacceptable.

Hot hardness is why the quick cutter got its name. Metal processing causes the tool to become very hot.

Traditional tool steel fixtures, if you look at the temperature-hardness ratio chart, fell into the abyss after the 200-degree threshold. High-speed steel easily held 60 HRC at 600.

The most advanced alloys with a high cobalt content and 700 degrees. When using cooling, the cutting speed was enormous and fully satisfied all requirements.

Strength or impact resistance is very important for a tool. When the cutting edge withstood shock loads without consequences, especially during slotting operations, intermittent turning and milling. High-speed steel tools easily coped with this on par or better than tool steels.

Application of high-speed steel tools

Strong vibration, processing with low cooling and intermittent turning are the right place for cobalt high-speed cutters R9K5, R9K10. The most difficult to machine and corrosion-resistant steels are their field.

For delicate and precise processing, with a small allowance, R9F5, R14F4 or vanadium quick-cutters are used.

For truly hellish conditions, large allowances and the hardest materials of all varieties, R9M4, R6M3 tungsten-molybdenum high-speed steels are more suitable than ever.

P18 and P9 are widely used. They are used to make cutters, drills, and turning tools. Also reamers, countersinks and a huge number of all kinds of shaped tools.

High-speed steel tools have a history of more than a century, but they are neck and neck with diamond, sintered and carbide tools. And where they are used today, they cannot be replaced. So far there is nothing to replace them, which means their story is not over yet.

Scheme of heat treatment of high-speed steel

Source: https://xn----dtbhlufccvfemek.xn--p1ai/novosti/item/359-instrumenty-iz-bystrorezhushchej-stali

Quick cutter

High-speed steels are alloy steels intended primarily for the manufacture of metal-cutting tools operating at high cutting speeds.

High-speed steel must have high fracture resistance, hardness (in cold and hot states) and red resistance.

Carbon tool steels also have high fracture resistance and cold hardness. However, tools made from them are not able to provide high-speed cutting conditions. Alloying high-speed steels with tungsten, molybdenum, vanadium and cobalt ensures hot hardness and red-hardness of the steel.

From stock: Р6М5 | >>>, P9 | >>>, R9K5 | >>>, P18 | >>>, 9Х4М3Ф2AGСТ | >>>, 11R3AM3F2 | >>> :: circle, sheet, stripe.

Hot hardness

At normal temperatures, the hardness of carbon steel is even slightly higher than the hardness of high-speed steel. However, during operation of the cutting tool, intense heat is generated. In this case, up to 80% of the released heat is spent on heating the instrument. Due to an increase in the temperature of the cutting edge, the tool material begins to temper and its hardness decreases.

After heating to 200 °C, the hardness of carbon steel begins to rapidly decrease. For this steel, a cutting mode in which the tool would heat up above 200 °C is unacceptable. High-speed steel retains its high hardness when heated to 500–600 °C. High speed steel tools are more productive than carbon steel tools.

Manufacturing and processing of high-speed steels

High-speed steels are produced both by the classical method (casting steel into ingots, rolling and forging) and by powder metallurgy methods (spraying a jet of liquid steel with nitrogen)[3]. The quality of high-speed steel is largely determined by the degree of its forging. When insufficient forging of steel produced by the classical method, carbide segregation is observed.

A common mistake when making high-speed steels is to treat them as “self-hardening steels.” That is, it is enough to heat the steel and cool it in air, and you can get a hard, wear-resistant material. This approach absolutely does not take into account the features of high-alloy tool steels.

Before hardening, high-speed steels must be annealed. In poorly annealed steels, a special type of defect is observed: naphthalene fracture, when, despite the normal hardness of the steel, it has increased brittleness.

A competent choice of quenching temperature ensures maximum solubility of alloying additives in α-iron, but does not lead to grain growth.

After quenching, 25–30% retained austenite remains in the steel. In addition to reducing the hardness of the tool, retained austenite leads to a decrease in the thermal conductivity of steel, which is extremely undesirable for working conditions with intense heating of the cutting edge.

Reducing the amount of retained austenite is achieved in two ways: by cold treating the steel or by repeated tempering [3]. When processing steel by cold, it is cooled to −80−70 °C, then tempered. When tempering multiple times, the “heating-holding-cooling” cycle is carried out 2-3 times.

In both cases, a significant reduction in the amount of retained austenite is achieved, but it is not possible to completely get rid of it.

Application

In recent decades, the use of high-speed steel has been declining due to the widespread use of hard alloys. High-speed steel is used mainly for making end tools (taps, drills, cutters of small diameters). In turning, cutters with replaceable and brazed carbide inserts have almost completely replaced cutters made of high-speed steel.

There are the following recommendations for the use of domestic grades of high-speed steels.

P9 steel is recommended for the manufacture of tools of simple shapes that do not require a large amount of grinding, for processing common structural materials. (cutters, cutters, countersinks).

For shaped and complex tools (for cutting threads and teeth), for which the main requirement is high wear resistance, it is recommended to use P18 (tungsten) steel.

Cobalt high-speed steels (R9K5, R9K10) are used for processing parts made of difficult-to-machine corrosion-resistant and heat-resistant steels and alloys, under conditions of intermittent cutting, vibration, and insufficient cooling.

Vanadium high-speed steels (R9F5, R14F4) are recommended for the manufacture of tools for finishing (broaches, reamers, shaver). They can be used for processing difficult-to-cut materials when cutting chips with a small cross-section.

Tungsten-molybdenum steels (R9M4, R6M3) are used for tools operating in roughing conditions, as well as for the manufacture of broaches, cutters, shaver, and milling cutters.

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Source: http://uraltermo.ru/sortament/bystrorez/

Learn more about high-speed steels, their history, manufacturing methods and applications

4 October 2017 14:23

// Metalworking

What steels are called high-speed? High-speed alloys belong to the group of special-purpose tool steels. Their main area of ​​application is the production of professional tools of increased strength, operating at high rotation and cutting speeds.

Before the advent of high-speed tool steels, ordinary steel cutters were used for turning wooden parts and non-ferrous metal products. But when processing parts made of hard materials with such a tool, a problem arose. The cutter wore out very quickly, heated up, and it was impossible for them to grind the product at high speed.

The problem was solved in 1858, after obtaining an alloy in which tungsten and manganese were used as alloying elements. Over the next few decades, as a result of experiments, several more types of ultra-strong alloys capable of operating at high temperatures were obtained. This made it possible to significantly increase the processing speed of parts and increase the productivity of metal-cutting machines.

At the end of the last century, tungsten compounds began to be replaced by self-hardening ones, and now tungsten-free compounds are successfully used.

Properties and types of high-speed steels

The alloys combine increased heat resistance with hardness, wear resistance and high resistance to plastic deformation. During operation, a high-speed steel tool must maintain a given size and shape, withstand severe dynamic loads, and maintain cutting ability at high temperatures.

The purpose of high-speed steels and their properties are determined by the characteristics of alloying elements. The composition includes chromium and tungsten in various percentages, which slightly change the performance characteristics of the material. In addition to classic chrome-tungsten compositions, alloys with increasing compositions of carbon, vanadium, and cobalt are used.

High-speed tool steels are divided into 3 groups:

• Alloys with normal heat resistance are tungsten and tungsten-molybdenum compounds (P9, P12, P18, P6M3, P6M5, P8M3), which are used for the manufacture of cutting tools for processing structural, non-ferrous and ferrous metals, and plastics. This group also includes compounds alloyed with nitrogen to improve the cutting characteristics of the metal.
• Grades with increased heat resistance are compositions with an increased content of carbon, vanadium and cobalt (10Р6М5, Р2МЗФ8, Р9К10, etc.) intended for processing hardened, heat-resistant, stainless and structural metals.
• Highly alloyed alloys with high heat resistance are characterized by a high content of alloying additives and low carbon content (V14M7K25, V11M7K23). They are designed for cutting titanium alloys and difficult-to-cut products.

Main characteristics

• Hot hardness In its normal state, the material is inferior in hardness to carbon metals. But during the heating process, the hardness of ordinary carbon compounds drops to unacceptable limits. The hardness of high speed steel is maintained even at a temperature of 600°C.
• Red resistance This parameter characterizes the maximum time during which the tool can withstand high temperatures without losing its performance properties. High-speed equipment has no analogues in this regard.
• Resistance to Fracture Strong alloys have excellent mechanical properties that prevent them from breaking. This guarantees the possibility of using the equipment in intensive operation.

Production of high-speed steels

The following technologies are used in production:

• The classic method of casting and forming metal followed by forging. This technology makes it possible to pre-anneal and harden the material, and also prevents the formation of brittleness and improves the quality characteristics of the tool.
• Powder method, during which the molten composition is sprayed with nitrogen.

To improve the quality of the resulting products, after manufacturing, their surface is subjected to additional treatment with nitrogen, zinc, and sulfur-containing sulfides.

Where are high speed steels used?

The scope of wear-resistant metal depends on the composition that determines its working properties. Basically, this is a tool that has high demands on strength, heat resistance, and long service life.

• Production of drills, cutters, cutters, taps;
• Manufacturing cutting edges for tools, which in some cases can be removable;
• Parts for metalworking machines and equipment;
• Manufacturing of tools used for finishing hard-to-cut metal products.

Experts give the following recommendations on the use of these metal grades:

• Tungsten-molybdenum compounds are suitable for tools intended for roughing products, manufacturing cutters, broaches and shaver.
• Cobalt compounds are used for processing heat-resistant and corrosion-resistant products in difficult conditions.
• Vanadium alloys are used for finishing materials.
• The P9 grade is used to create equipment elements that are not subject to excessive load.
• Grade P18 is suitable for tools with complex shapes and shaped products with increased wear resistance requirements.

The range of metal products is represented by square, circle, strip, and sheet metal. Most often, cutting tools are made from a circle. Square steel is used for the production of electric planers, knives, and turning tools. If you have doubts about the correct choice of a suitable alloy, it is better to contact specialists. Specialized companies will be able to select high-quality rental products with the required performance characteristics.

Source: https://indust.by/info/articles/metalloobrabotka/bystrorezhushchie-stali/

Description of high-speed steel R6M5

High-speed steels have high strength, which allows them to be used for processing hard materials. At the same time, the operating speed of cutting, grinding, and drilling installations exceeds those that can be achieved using parts made of tool steel. A special place in technology for high-speed samples was found in the manufacture of thread-cutting tools, especially those working with shock loads.

In general, high-speed cutters mean alloy steel, the composition of which may contain the following chemical elements:

• carbon, silicon, magnesium, nickel, sulfur, phosphorus, and cobalt less than 1%;

The quick cutter R6M5 has approximately the same chemical composition. Products made from such alloys are not only hard, but also have red resistance and hot hardness, and have toughness. Despite their tendency to decarbonize, they guarantee a relatively long service life as part of equipment components.

Decoding - what do the marking symbols mean?

What is the meaning of the abbreviation R6M5 - spelling out steel? Such designations turned out to be a legacy of Soviet times.

The letter "P" is a designation for high-speed steels. The word is taken from the transcription of the English “rapid”, translated as “fast”.

The number behind the letter “P” indicates the percentage of tungsten in the alloy. For the brand described, it fluctuates around 6% with minor deviations.

Next comes the letter “M” , indicating the presence of molybdenum in the alloy. The next parameter is the proportion of the substance present in the composition.

In addition to Mo, high-speed steels may contain the following designations in their markings: “K” - cobalt, “F” - vanadium, “T” - titanium, “C” - zirconium .

Analyzing further the abbreviation P6M5, the decoding of steel may include additional letters. If the metal is produced by electroslag remelting, the nomenclature “Ш” (Р6М5-Ш) .

With the introduction of new P6M5 technologies, decoding began to be found in this interpretation, P6AM5. This means alloying with nitrogen, which occurs at the stage of cooling the alloy after heating it to the hardening temperature (more details below).

This steel is used in the manufacture of milling wheels.

Drill from Japanese company Nachi made of HSS steel

Imported analogues of high-speed cutters are labeled as HSS, which means High Speed ​​Steel, literally translated, this is high-speed steel, and analogues of P6M5 are steels:

• S600/S601 (standard D-016);

• M2 (USA according to AISI/ASTM standards).

GOST and TU steel R6M5

R6M5 steel is described by several GOSTs and TUs. Each of them contains products and technical requirements for them. Despite the transition of rolled metal to hard alloys, the characteristics of R6M5 keep this brand in the field of view of many steel foundries. The following products, described by the relevant GOSTs or specifications, are still in demand:

• cold-deformed shaped profiles of high precision TU 14-11-245-88;

• forged circles or squares, assortment - GOST 1133-7;

• hot-rolled wheels - GOST 2590-88;

• calibrated rod - GOST 7417-75;

• rods and strips - GOST 19265-73 (steel grade R6M5K5);

Source: http://xlom.ru/spravochnik/opisanie-bystrorezhushhej-stali-r6m5/

High speed steels

There are a huge number of different metals that have their own specific advantages and disadvantages. High-speed steels are often used for the manufacture of tools that must have increased strength and some critical parts. Let's take a closer look at the features of this alloy.

High speed steels

Classification and marking of high-speed steels

All high-speed steels are classified directly according to their chemical composition, for which purpose the markings are deciphered. High-speed tool steels are divided into the following three groups:

1. Alloys with useful impurities, in which the percentage of cobalt is not more than 10%, and tungsten is 22%. The metal markings of this group are as follows: P10M4Ф3К10 and Р6М5Ф2К8 and others.
2. Alloys containing no more than 5% cobalt and up to 18% tungsten. The types of high-speed steel in this group are as follows: R9K5, R10F5K5 and others.
3. Metal options, the decoding of which determines the percentage of cobalt and tungsten more than 16%. Representatives of this group include brands P9 and P18, P12 and P6M5.

When using such a metal, the resulting edge does not react to mechanical stress, the hardness indicator remains unchanged along the entire length and the metal does not chip. The above classification of high-speed steel determines at what cutting speed and feed the alloy can be used.

Composition of high-speed steels of various grades

When considering the designation of high-speed steel, attention should be paid to the fact that the first letter to designate this group is “P”. The number that comes first in the designation indicates the process of tungsten in the composition. Next may be letters indicating alloying elements. It is worth considering that metal decoding indicates the exact content of certain alloying elements that change the performance properties of the material.

Scope of application of various grades of high-speed steels

When considering the use of wear-resistant metal, attention should be paid to the fact that the specific composition of the metal determines its performance qualities. A tool made from such metal can withstand long-term use.

High speed steel cutting tools

The scope is quite wide:

1. Making drills. Drills have a rather complex shape and design, which is obtained by casting.
2. Manufacturing of cutters. Today, to reduce the cost of cutters, their main part is made of inexpensive metal, and only the cutting edge is made of wear-resistant material.
3. Making brazes for cutting tools. In some cases, the cutting edge is replaceable.
4. Manufacturing of cutters. Milling cutters are also produced by casting molten metal.

The material can be used to obtain a tool that will withstand high loads.

Today, with the widespread installation of CNC machines, cutting tools with increased stability are the only way out of the current situation when high processing speeds create problems.

To increase the performance properties of high-speed steel, standard processing methods can be used. However, the composition of the metal is taken into account. As an example, the hardening process involves heating the medium to a temperature that allows for the dissolution of various impurities and additives.

After processing of high-speed steel has been completed, up to 30% austenite remains in the alloy, which significantly increases thermal conductivity and hardness.

To reduce the austenite index in the structure, two technologies can be used:

1. To improve the quality of heat treatment, heating is carried out in several stages. In this case, exposure is carried out at a certain temperature, and multiple tempering is also carried out.
2. Tempering involves cooling the workpiece to a low temperature, which is often - 800 degrees Celsius.
3. Quenching must be carried out at a sufficiently high temperature, since only in this case does a complete restructuring of the crystal lattice occur.
4. A variety of media are used for cooling. An example is the use of oil or salt baths. Ordinary water causes a variety of defects, such as cracks or scale. After this, additional processing must be performed to remove defects.

Microstructure of high-speed steel R6M5: a) cast state; b) after forging and annealing; c) after hardening; d) after vacation

In addition, performance improvements are carried out as follows:

1. The surface layer is saturated with zinc. In order to have the required effect on the surface, such an operation involves heating the surface to 5600 degrees Celsius. Exposure can last from 5 to 30 minutes.
2. Saturation of the surface with nitrogen may also occur. Most often, this procedure is carried out in a gas environment. The workpiece or part is kept for 10-40 minutes, the heating temperature varies in the range of 550-6600 degrees Celsius.
3. In some cases, the chemical composition of the metal is changed by sulfidation of the surface. In this way, the hardness and strength of the surface can be increased.
4. As an additional treatment, various materials are sprayed onto the surface. Due to this, the performance of the tool or part changes significantly.

Today, a situation often occurs when the surface is treated with steam, which can significantly improve the characteristics of the surface layer. Often additional processing is carried out when the cutting edge has been fully prepared.

Source: https://stankiexpert.ru/spravochnik/materialovedenie/bystrorezhushhie-stali.html

High-speed steel • en.knowledgr.com

High speed steel ( HSS or HS ) is a subset of tool steels commonly used in tool bits and cutting tools.

When used in machining against carbide cutting tools it actually cuts the material instead of shearing it.

It is often used in chainsaw blades and drill bits. It is superior to older high-carbon steel tools used extensively during the 1940s, in which it can withstand higher temperatures without losing its character (hardness).

This property allows HSS to cut faster than high-carbon steel, hence the name high-speed steel .

At room temperature, in their commonly recommended heat treatment, HSS grades typically exhibit high hardness (above HRC60) and abrasion resistance (usually attributed to the tungsten and vanadium content often used in HSS) compared to common carbon and tool steels.

Story

Although the development of modern high-speed steel began in the second half of the 19th century, there is recorded evidence of similar levels of steel produced earlier. These include fortified steels in China in the 13th century BC.

uh, wootz steel produced in India around 350 BC and production of Damascus and Japanese laminated steel blades in 540 AD. e. and 900 N. e.

The high-speed properties of those steels would be mostly accidental, and the result of local iron ores containing natural traces of tungsten or other favorable alloying ingredients.

https://www.youtube.com/watch?v=G5mhsyV3-gA

In 1868, English metallurgist Robert Forester Mushet developed Mushet steel, which is believed to be the forerunner of modern high-speed steels. It consisted of 2% carbon (C), 2.5% manganese (Mn) and 7% tungsten (W).

The main advantage of this steel was that it strengthened when the air cooled from the temperature at which most steels had to be pressed to strengthen.

Over the next 30 years, the most significant change was the replacement of manganese (Mn) with chromium (Cr).

In 1899 and 1900, Frederick Winslow Taylor and Moncel White, working with a team of assistants at the Bethlehem Iron and Steel Company in Bethlehem, Pennsylvania, USA, performed a series of high-temperature experiments examining existing high-quality tool steels such as Mushet steel; heating them to much higher temperatures than was generally considered desirable in industry.

Their experiments were characterized by scientific empiricism in that many different combinations were made and tested without regard to conventional wisdom or alchemical recipes, and with detailed records kept by each party.

The end result was a heat treatment process that transformed existing alloys into a new kind of steel that could retain its hardness at higher temperatures, allowing much higher speeds and cutting rates when machining.

The Taylor-white process was patented and created a revolution in the machining industries, effectively requiring whole new, heavier machine tool designs so the new steel could be used to its full potential. The patent was hotly contested and ultimately revoked.

The first alloy to be formally classified as high-speed steel is known by the designation T1 AISI, which was introduced in 1910. It was patented by Crucible Steel Co. at the beginning of the 20th century.

Although molybdenum-rich high-speed steels such as AISI M1 have been in use since the 1930s, significant shortages and high costs caused by World War II encouraged the development of less expensive alloys replacing molybdenum with tungsten. Advances in molybdenum-based high-speed steels during this period place them on par with and in certain cases better than tungsten-based high-speed steels. This started with the use of M2 steel instead of T1 steel.

Types

High-speed steels are alloys that get their properties from either tungsten or molybdenum, often with a combination of the two. They belong to the Fe–C–X multi-component alloy system, where X represents chromium, tungsten, molybdenum, vanadium or cobalt.

Typically X components are present in excess of 7%, along with carbon at greater than 0.60%.

The percentages of the alloying element do not alone grant hardness-preserving properties; they also require appropriate high temperature heat treatment to become true HSS; see Story above.

In the Unified Numbering System (UNS), tungsten type grades (eg T1, T15) are assigned numbers in the T120xx series, while molybdenum (eg M2, M48) and intermediate types are T113xx. American Society for Testing and Materials standards recognize 7 tungsten types and 17 molybdenum types.

The addition of approximately 10% tungsten and molybdenum in total effectively maximizes the hardness and toughness of high-speed steels and maintains those properties at the high temperatures produced by cutting metals.

In general, the basic composition of T1 HSS is 18% W, 4% Cr, 1% B, 0.7% C and the remainder Fe. Such an HSS tool could machine (turn) mild steel at speeds of up to 20~30 m/min (which was quite significant at the time).

M2

M2 is a molybdenum based high speed steel in the tungsten molybdenum series. The carbides in it are small and evenly distributed. It has high wear resistance. After heat treatment, its hardness is the same as T1, but its bending force can reach 4700MPa, and its toughness and thermoplasticity are higher than T1 by 50%. It is commonly used to produce a variety of tools such as drills, taps and reamers. Its decarburization sensitivity is a little high.

M35

M35 is similar to M2 but with 5% cobalt added. Adding cobalt increases thermal resistance. M35 is also known as HSSE or HSS-E.

M42

M42 is an alloy of high-speed steel of the molybdenum series with an additional 8% cobalt.

It is widely used in the metal manufacturing industry due to its superior red hardness compared to more conventional high-speed steel, allowing for shorter cycle times in manufacturing environments due to higher cutting speeds or from increasing in time between tool changes.

The M42 is also less susceptible to splintering when used for interrupted cuts and costs less when compared to the same tool made from carbide. Tools made from cobalt-bearing high-speed steels can often be designated by HSS-Co letters.

Coatings

To increase the life of high speed steel, tools are sometimes coated. One such coating is TiN (titanium is nitrided). Most coatings generally increase the hardness and/or lubricity of the tool. The coating allows the leading edge of the tool to pass cleanly through the material without any material malice (stick) to it. The coating also helps reduce the temperature associated with the cutting process and increase tool life.

Surface modification

Lasers and electron beams can be used as sources of intense heat in surfaces for heat treatment, re-melting (glazing) and compositional modification. It is possible to achieve different cast pool shapes and temperatures. Cooling rates range from 10 to 10 K s. Helpfully, there is minimal formation of cracking or porosity.

While the possibilities of thermal viewing at a surface should be readily apparent, other applications require some explanation. At cooling rates above 10 K s, the eutectic trace elements disappear and there is extreme segregation of replacement alloying elements. This has the effect of providing the benefits of the glazed part without the associated mileage of fashion damage.

The alloy composition of a part or tool can also be changed to form a high-speed steel on the surface of a lean alloy or to form an alloy or carbide enriched layer on the surface of a high-speed steel part.

Several methods can be used, such as foil, package boriding, plasma spray powders, powder cored strips, inert gas shock feeders, etc.

Although this method has been reported to be both profitable and stable, it has yet to see widespread commercial use.

Statements

The main use of high speed steel continues to be in the production of various cutting tools: drills, taps, grinders, tool bits, gear cutters, saw blades, planer and jointer blades, router bits, etc., although the use for impacts is dying out. increases.

High-speed steels also found a market in fine hand tools, where their relatively good toughness in high hardness, coupled with high frictional resistance, made them suitable for low-speed applications requiring a long lasting sharp (sharp) edge, such as files, chisels, aircraft hand blades , and high quality kitchen, pocket knives and swords.

High-speed steel tools are the most popular for use in woodturning because the speed of work moving past the edge is relatively high for portable tools, and HSS holds its edge much longer than high-carbon steel tools can.

see also

• Crucible Industries

• List of steel manufacturers

External links

• Effects of the elements on steel

• Comparison table for different quality standards of High Speed ​​Steel (HSS)

Source: http://ru.knowledgr.com/01296967/%D0%91%D1%8B%D1%81%D1%82%D1%80%D0%BE%D1%80%D0%B5%D0%B6 %D1%83%D1%89%D0%B0%D1%8F%D0%A1%D1%82%D0%B0%D0%BB%D1%8C