HSS steel – bds-machines.by
The name in the form of the abbreviation HSS is a bulk group of steels. They got their name from the first letters of words in English - High Speed Steel, or high-speed steel. Most often it is used to produce cutters, taps and dies for creating threads. It is much less common to find blades for hacksaws and knives made from similar materials.
Characteristics and grades of HSS steel
High-speed varieties are high-carbon steels. Some brands contain a fairly large amount of tungsten. In addition, they may contain cobalt and molybdenum. If we talk about the hardness of alloys, the indicator is most often in the range of 62–64 units of the HRC scale. Comparing products made from high-speed steel and carbide, it is worth noting that the first option is distinguished by a fairly affordable price and increased wear resistance.
Recently, it has been customary to distinguish 3 main groups of HSS steel, each of which has its own characteristics:
- High tungsten content (T)
- High Molybdenum (M)
- High alloy
Tungsten steels
Not the most popular variety. This is due to the fact that tungsten is quite rare and expensive. The most common grades of tungsten steel are T1 and T15. The second contains cobalt and vanadium, therefore they are suitable for the production of accessories that have increased requirements for strength and resistance to high temperatures.
Chemical composition of tungsten HSS steels
| Type | Analogue | C | Mn | Si | Cr | V | W | Mo | Co | Ni |
| T1 | P18 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | — | — |
| T2 | R18F2 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | — | — |
| T4 | R18K5F2 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | 5,00 | — |
| T5 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | 8,00 | — | |
| T6 | 0,80 | — | — | 4,50 | 1,50 | 20,00 | — | 12,00 | — | |
| T8 | 0,75 | — | — | 4,00 | 2,00 | 14,00 | — | 5,00 | — | |
| T15 | R12K5F5 | 1,50 | — | — | 4,00 | 5,00 | 12,00 | — | 5,00 | — |
Molybdenum and high alloy steels
They are very widespread. May contain cobalt and tungsten. Those brands whose formula includes carbon and vanadium are characterized by increased strength and wear resistance, and resistance to abrasives.
Alloys, starting with M41, are used to produce devices that retain their characteristics even when super heated.
To create equipment designed for work at low temperatures, steels with molybdenum are also used, but they are subject to additional processing.
Chemical composition of molybdenum HSS steels
| Type | Analogue | C | Mn | Si | Cr | V | W | Mo | Co | Ni |
| M1 | 0,80 | — | — | 4,00 | 1,00 | 1,50 | 8,00 | — | — | |
| M2 | P6M5 | 0,85 | — | — | 4,00 | 2,00 | 6,00 | 5,00 | — | — |
| M3 | P6M5Ф3 | 1,20 | — | — | 4,00 | 3,00 | 6,00 | 5,00 | — | — |
| M4 | 1,30 | — | — | 4,00 | 4,00 | 5,50 | 4,50 | — | — | |
| M6 | 0,80 | — | — | 4,00 | 2,00 | 4,00 | 5,00 | — | — | |
| M7 | 1,00 | — | — | 4,00 | 2,00 | 1,75 | 8,75 | — | — | |
| M10 | 0,85–1,00 | — | — | 4,00 | 2,00 | — | 8,00 | — | — | |
| M30 | 0,80 | — | — | 4,00 | 1,25 | 2,00 | 8,00 | — | — | |
| M33 | 0,90 | — | — | 4,00 | 1,15 | 1,50 | 9,50 | — | — | |
| M34 | 0,90 | — | — | 4,00 | 2,00 | 2,00 | 8,00 | — | — | |
| M35 | R6M5K5 | 0,82–0,88 | 0,15–0,40 | 0,20–0,45 | 3,75–4,50 | 1,75–2,20 | 5,5–6,75 | 5,00 | 4,5–5,5 | up to 0.30 |
| M36 | 0,80 | — | — | 4,00 | 2,00 | 6,00 | 5,00 | — | — |
Chemical composition of high alloy HSS steels
| Type | Analogue | C | Mn | Si | Cr | V | W | Mo | Co | Ni |
| M41 | R6M3K5F2 | 1,10 | — | — | 4,25 | 2,00 | 6,75 | 3,75 | 5,00 | — |
| M42 | 1,10 | — | — | 3,75 | 1,15 | 1,50 | 9,50 | 8,00 | — | |
| M43 | 1,20 | — | — | 3,75 | 1,60 | 2,75 | 8,00 | 8,25 | — | |
| M44 | 1,15 | — | — | 4,25 | 2,00 | 5,25 | 6,25 | 12,00 | — | |
| M46 | 1,25 | — | — | 4,00 | 3,20 | 2,00 | 8,25 | 8,25 | — | |
| M47 | R2AM9K5 | 1,10 | — | — | 3,75 | 1,25 | 1,50 | 9,50 | 5,00 | — |
| M48 | 1,42–1,52 | 0,15–0,40 | 0,15–0,40 | 3,50–4,00 | 2,75–3,25 | 9,50–10,5 | 0,15–0,40 | 8,00–10,0 | up to 0.30 | |
| M50 | 0,78–0,88 | 0,15–0,45 | 0,20–0,60 | 3,75–4,50 | 0,80–1,25 | up to 0.10 | 3,90–4,75 | — | up to 0.30 | |
| M52 | 0,85–0,95 | 0,15–0,45 | 0,20–0,60 | 3,50–4,30 | 1,65–2,25 | 0,75–1,50 | 4,00–4,90 | — | up to 0.30 | |
| M62 | 1,25–1,35 | 0,15–0,40 | 0,15–0,40 | 3,50–4,00 | 1,80–2,00 | 5,75–6,50 | 10,0–11,0 | — | up to 0.30 |
When selecting products made from molybdenum material, it is worth considering the features of a particular brand:
- M1. Ideal for releasing drills. They are flexible and shock resistant. But they cannot boast of significant red fastness.
- M2. One of the most popular materials. Often used for the production of tools for various purposes. The product is suitable for intensive work using machines. The peculiarity of such a tool is its exceptional red resistance, which means the cutting element will retain its qualities for a long time. Our catalog presents drills of the HSS-STANDARD series made of this alloy
- M7. Ideal for producing large drills designed for drilling materials of increased hardness or thick sheets.
- M35. It has increased red fastness due to the increased amount of cobalt in the formula. But it has low resistance to shock loads.
- M42. Contains a large amount of cobalt, therefore it has excellent red fastness. In addition, it is extremely resistant to abrasion. Ideal for making accessories for working with particularly hard or even viscous materials. Core cutters made from this material are presented in the HSS-CO 8 line of drills
- M50. Often used to produce drills that come with portable equipment.
Red resistance is a property that alloys obtain due to the presence of tungsten in their composition. The whole point of this feature is that the cutting edge of the equipment retains all its characteristics even if exposed to a temperature of 530 degrees. Steels with cobalt in the formula can withstand even greater heat.
Symbols and markings of HSS steels
To learn more about the material from which the equipment is made, the existing markings on it will help. There are several varieties:
- HSS or HSS R. Drills of this type are considered the most unstable to damage.
- HSS G. The cutting part of the equipment undergoes additional grinding with Borazon. The products are highly durable. They practically do not create beating during operation.
- HSS E. Contains cobalt. Analogues: M35 and HSS-Co. Ideal for drilling complex workpieces and elements.
- HSS G TiN. Coated with titanium nitride. It is characterized by increased strength and heat resistance.
- HSS G TiAIN. The titanium nitride coating is additionally alloyed with aluminum. This approach makes it possible to increase thermal resistance to 900 degrees.
- HSS E VAP. Products made from this alloy are excellent for working with stainless steel.
Source: http://bds-machines.by/spravochnik/hss-stal/
How to choose metal drills
For drilling metals, screw or, as they are more often called, twist drills are used. Although almost identical in design, these tools may differ in material, type of additional processing, and sharpening features. There are many varieties of drill bits optimized for different metals, drilling depths and other working conditions.
What are drills made of?
High-speed steel is used to make metal drills. This is a group of highly alloyed alloys, which, in addition to iron and carbon, include tungsten, molybdenum, cobalt, vanadium and other elements.
High-speed steel differs from ordinary tool steel in that a drill made from it remains operational when heated. Tool steel at normal temperatures is not inferior in hardness to high-speed steel, but when heated above 200°C, tempering occurs and it becomes soft. High-speed steel retains hardness up to 500-600°C, and some grades – up to 1000°C.
Tungsten is the main component that increases the “red resistance of steel” (the ability to maintain hardness when heated). However, due to limited reserves of tungsten, it was necessary to abandon steel with a high tungsten content and switch to molybdenum alloys. When the tungsten content is within 6%, the required qualities of drills are ensured by the addition of molybdenum, cobalt and other elements. Tools made from P18 steel are no longer produced, and even P9 is rare.
In foreign classifications, high-speed alloys are designated by the abbreviation HSS (High Speed Steel). There are several varieties of them, and some of them are similar to the alloys specified in GOST. High-speed steel grades are designated by the letter “M” followed by a number. Let's compare several of the most commonly used brands.
M1
Steel with low tungsten content and high molybdenum content (1.5 and 8%, respectively). It is not highly durable and is used for the manufacture of general purpose drills.
M2
The alloy contains 6% tungsten and 5% molybdenum, which gives drills made from it high hardness. The Russian analogue is R6M5. Drills made from this steel have good wear resistance and red resistance.
M7
Drills made of this steel are used for deep drilling and high-force work. Its composition has a reduced tungsten content (1.75%), but an increased amount of molybdenum (8.75%) and vanadium (2%). The Russian analogue is R2M9.
M35
The Russian analogue of this alloy is R6M5K5. This steel differs from M2 (R6M5) in its higher “red resistance” due to the addition of 5% cobalt. The alloy also contains silicon, magnesium and nickel. Drills made of M35 steel can withstand high heat and provide high performance.
M42
This alloy contains a little tungsten, but a high content of molybdenum and cobalt. Drills made from it have high red resistance and hold an edge well. Work well at high cutting speeds and on tough materials. The Russian analogue is R2M10K8 steel.
Features of drills and their markings
The foreign marking system for drills reflects some of the features of their manufacture and the most important components of steel.
HSS-R
Unground drills are produced by helical rolling. They use relatively soft, deformable steel. After rolling, the tool is hardened. The letter “R” may be missing from the marking.
HSS-G
Ground drills are made by grinding CBN (cubic boron nitride). This is the most common type of tool for a wide range of tasks. The drills have high wear resistance and minimal radial runout.
HSS-PM
Drills made using powder metallurgy technology. Used for processing hard metals.
HSS-E (HSS-Co)
Cobalt drills made from alloys with a high cobalt content. A number may be added to the marking indicating the percentage of cobalt rounded to the nearest whole number. For example, HSS-Co5 or HSS-Co8, which corresponds to M35 or M42 alloys.
HSS-TiN or HSS-TiAN
Titanium drills are coated with titanium nitride. The letter “A” in the second option means aluminum alloying. Titanium nitride coating gives the tool a golden color and increases its wear resistance several times.
HSS-E-VAP
Steam oxidized drills. Drills of this group are covered with a film of oxides, which is created by steam oxidation - treatment with superheated steam in a special environment. The coating is black in color, reduces the adhesion of chips to cutting edges, and increases surface wettability with coolant. HSS-E-VAP drills are effective for drilling stainless steel and other tough alloys.
The hardness of drills made of high-speed steels according to GOST 2034-80 should be in the range of 63-66 HRC.
Cutting part
Cutting when drilling is carried out by two edges, which are formed by the intersection of the front surfaces of the helical grooves and the conical head of the drill. Strictly speaking, the cutting part is not completely conical: the back surface of the blade decreases, moving away from the theoretical cone at a slight angle.
The main sharpening parameter is the tip angle. For most applications it is around 118o. For cast iron or hard bronze it can be reduced to 116o. For brass, soft bronze, aluminum, angles of 120°, 130°, 140° are used.
For drilling soft sheet metal, a special sharpening is used with curved cutting edges, a protruding pointed center and slightly protruding edge cutters. At the beginning of drilling, the drill is immediately clearly centered, then a contour is outlined, and after that the extraction of metal begins over the entire area of the hole. As a result, beating at the inlet and biting of the edges at the outlet are eliminated.
For drilling steel and cast iron, double-sharpened drills are used. In addition to the apex angle of 116 - 118°, the edges are ground at the periphery, to a width of 0.2 diameters, at an angle of 70 - 75°. There are other forms of sharpening for specific applications.
Drilling accuracy
Factors affecting drilling accuracy are divided into two groups: equipment-dependent and tool-dependent. Drills are divided into three accuracy classes: A1, B1 and B. The accuracy class is determined by the maximum permissible values:
- asymmetry of the core and driver of the drill;
- radial runout;
- tolerance for straightness of cutting edges.
The accuracy class must correspond to the required quality of hole accuracy and equipment capabilities. Drills of class A1 are used for holes from 10 to 13 accuracy grades. Drills of classes B1 and B – up to 14 and up to 15 accuracy grades, respectively.
Types of shanks
The tail part of the drill, intended for mounting in a machine or hand tool, can have different shapes.
- Cylindrical shank. This is the most common form of shank and is suitable for being held in the chuck of a drill, drill or lathe.
- Conical (Morse taper). Drills with a conical shank are used on industrial equipment. They require a corresponding taper on the spindle. They are distinguished by reliable fixation, precise centering and quick tool replacement.
- Hexagonal. This shank is suitable for installation in a three-jaw chuck and is characterized by reliable transmission of high torque. Eliminates slipping of the drill in the chuck. In addition, the hexagonal shape is convenient for installing a drill bit into a screwdriver adapter. In this case, the drill does not need to be clamped, but its exact position during operation is not ensured.
Popular sets and specially shaped drills
The most commonly used drills are with a diameter of 2 to 10 mm. They are used in metalworking workshops, service stations, and households. The popularity of these diameters is also indicated by the fact that most lightweight drilling equipment has chucks adapted to this size range.
For general use, a set of drill bits with a diameter pitch of 0.5 mm is suitable. In most cases, such a set will cover the basic drilling needs. For a specific application, diameters can be selected in increments of 0.1 mm. More precise hole sizes can be achieved through additional processing.
There are special cases for which it is convenient to use special drills:
- step drill for sheet materials;
- annular drill or centrifuge for shallow through drilling of large diameter holes;
- a combination drill-tap that can be used to drill a hole and tap a thread in one pass.
Choosing the right tool for the intended application will greatly simplify the work and help achieve the desired quality.
Source: https://uni-tool.ru/blog/kak-vybrat-sverla-po-metallu/
What is HSS steel? Types and domestic analogues of HSS
HSS (High Speed Steel) is a general definition of a group of high-speed steels. HSS steel is used to manufacture a large number of different cutting tools. Typically, these are drills, cutters, taps and dies, less often - knives and saw blades. HSS steels are high carbon and some contain a large proportion of tungsten.
Typically, HSS steel tools have a hardness of 62-64 HRC. The main advantage over carbide tools is the durability and lower cost of the tools. Therefore, HSS performs well in interrupted cutting. A limitation of the use of HSS is the low cutting speeds compared to carbide.
Abroad, as well as here, at the end of the 19th century, HSS steels with a high tungsten content (18%) were the first to be used. The first record of the use of cobalt in steels appeared in Germany in 1912. Later, in 1930, molybdenum was introduced into the United States.
Characteristics of HSS steels
HSS steels are divided into three groups:
- Tungsten (T);
- Molybdenum (M);
- High-alloy high-speed steels.
Tungsten steels are practically not used today due to the high cost of tungsten and its shortage. The most common are T1 general purpose steel and T15 vanadium cobalt steel. T15 is used for tools operating under conditions of high temperatures and wear.
Molybdenum group steels have molybdenum as their main alloying element, although some contain equal or greater amounts of tungsten and cobalt. Steels with a high content of vanadium and carbon are resistant to abrasive wear.
A series of steels starting from M41 is characterized by high hardness when operating at high temperatures (red resistance). Molybdenum steels are also used in the manufacture of tools operating in “cold” conditions - rolling dies, cutting dies.
In such cases, HSS steels are hardened to lower temperatures to improve toughness.
Table of common chemical compositions of HSS steels. Domestic analogues.
| Type | Fatherland analogue | Chemical composition, % | ||||||||
| C | Mn | Si | Cr | V | W | Mo | Co | Ni | ||
| Tungsten HSS steels | ||||||||||
| T1 | P18 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | — | — |
| T2 | R18F2 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | — | — |
| T4 | R18K5F2 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | 5,00 | — |
| T5 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | 8,00 | — | |
| T6 | 0,80 | — | — | 4,50 | 1,50 | 20,00 | — | 12,00 | — | |
| T8 | 0,75 | — | — | 4,00 | 2,00 | 14,00 | — | 5,00 | — | |
| T15 | R12F5K5 | 1,50 | — | — | 4,00 | 5,00 | 12,00 | — | 5,00 | — |
| Molybdenum HSS steels | ||||||||||
| M1 | 0,80 | — | — | 4,00 | 1,00 | 1,50 | 8,00 | — | — | |
| M2 | R6M5 | 0,85 | — | — | 4,00 | 2,00 | 6,00 | 5,00 | — | — |
| M3 | R6M5F3 | 1,20 | — | — | 4,00 | 3,00 | 6,00 | 5,00 | — | — |
| M4 | 1,30 | — | — | 4,00 | 4,00 | 5,50 | 4,50 | — | — | |
| M6 | 0,80 | — | — | 4,00 | 2,00 | 4,00 | 5,00 | — | — | |
| M7 | 1,00 | — | — | 4,00 | 2,00 | 1,75 | 8,75 | — | — | |
| M10 | 0,85-1,00 | — | — | 4,00 | 2,00 | — | 8,00 | — | — | |
| M30 | 0,80 | — | — | 4,00 | 1,25 | 2,00 | 8,00 | — | — | |
| M33 | 0,90 | — | — | 4,00 | 1,15 | 1,50 | 9,50 | — | — | |
| M34 | 0,90 | — | — | 4,00 | 2,00 | 2,00 | 8,00 | — | — | |
| M35 | R6M5K5 | 0,82-0,88 | 0,15-0,40 | 0,20-0,45 | 3,75-4,50 | 1,75-2,20 | 5,5-6,75 | 5,00 | 4,5-5,5 | up to 0.30 |
| M36 | 0,80 | — | — | 4,00 | 2,00 | 6,00 | 5,00 | — | — | |
| High alloy HSS steels | ||||||||||
| M41 | R6M3K5F2 | 1,10 | — | — | 4,25 | 2,00 | 6,75 | 3,75 | 5,00 | — |
| M42 | 1,10 | — | — | 3,75 | 1,15 | 1,50 | 9,50 | 8,00 | — | |
| M43 | 1,20 | — | — | 3,75 | 1,60 | 2,75 | 8,00 | 8,25 | — | |
| M44 | 1,15 | — | — | 4,25 | 2,00 | 5,25 | 6,25 | 12,00 | — | |
| M46 | 1,25 | — | — | 4,00 | 3,20 | 2,00 | 8,25 | 8,25 | — | |
| M47 | R2AM9K5 | 1,10 | — | — | 3,75 | 1,25 | 1,50 | 9,50 | 5,00 | — |
| M48 | 1,42-1,52 | 0,15-0,40 | 0,15-0,40 | 3,50-4,00 | 2,75-3,25 | 9,50-10,5 | 0,15-0,40 | 8,00-10,0 | up to 0.30 | |
| M50 | 0,78-0,88 | 0,15-0,45 | 0,20-0,60 | 3,75-4,50 | 0,80-1,25 | up to 0.10 | 3,90-4,75 | — | up to 0.30 | |
| M52 | 0,85-0,95 | 0,15-0,45 | 0,20-0,60 | 3,50-4,30 | 1,65-2,25 | 0,75-1,50 | 4,00-4,90 | — | up to 0.30 | |
| M62 | 1,25-1,35 | 0,15-0,40 | 0,15-0,40 | 3,50-4,00 | 1,80-2,00 | 5,75-6,50 | 10,0-11,0 | — | up to 0.30 |
Not all analogues may be indicated in the table, since at present there may be a large number of borrowed, non-governed brands.
A cutting tool made with tungsten content (W) will have a very useful quality for the tool - red resistance. It allows tools to maintain a sharp cutting edge and hardness at red-hot temperatures (up to 530°C). Cobalt further increases the red hardness and wear resistance of HSS steels.
M1 . Used for the production of drills for a wide range of applications. M1 steels have lower red resistance than M2 steels, but are less susceptible to impact and are more flexible, making them suitable for general work.
M2 . Standard material for making tools from HSS steels. M2 has good red hardness and retains its cutting edge longer than other HSS steels with lower tungsten content. Typically used for the manufacture of tools for high-performance machine work.
M7 . Used for heavy-duty drills for drilling hard sheet metal. Typically used where flexibility and extended service life are equally important.
M50 . Used to make drill bits that are used for drilling on portable equipment where breakage due to bending is a problem. Does not have the same red resistance as other HSS tungsten steels.
M35 . M35 steels have increased red resistance compared to M2. At the same time, cobalt slightly reduces impact resistance.
M42 . M42 “Super Cobalt” steels have excellent abrasion resistance and good red-hardness. Used for work on viscous and complex materials.
Legend
The markings of foreign manufacturers do not fully disclose the chemical composition of the HSS steel from which the tool is made. It is assumed that a particular tool is designed for the tasks assigned to it, described in the catalog, and this should be sufficient.
The remaining details can be found out either by determining the chemical composition with the same portable metal analyzer or experimentally. In addition, such marking is convenient for an unscrupulous manufacturer, who can make a drill from HSS steel that will not meet the necessary requirements, despite the fact that it is high-speed.
Typical markings are described below, by which you can partially determine the material from which the tool is made and its scope of application.
HSS-R (sometimes just HSS) is a designation on drills that have undergone roller rolling and heat treatment. Drills have the lowest durability.
HSS-G is a designation on tools made from HSS steels in which the cutting part is ground with CBN (cubic boron nitride). Tools with increased tool life and less radial runout. HSS-G tools are the most common cutting tools for standard applications.
HSS-E - tools made of HSS steel type M35 with the addition of cobalt. Used for working on viscous and complex materials. You will also find designations such as HSS Co 5 and HSS Co 8 , which indicate the exact cobalt content.
HSS-G TiN is a tool surface coated with titanium nitride. Thanks to this coating, the surface hardness increases by approximately 2300 HV, and the heat resistance increases by up to 600°C.
HSS-G TiAlN is a tool surface coated with titanium-aluminum-nitride. Thanks to this coating, the surface hardness increases by approximately 3000 HV, and the heat resistance increases by up to 900°C.
HSS-E VAP - VAP tools, due to their properties, are used for machining stainless steels (V2A and V4A). The method of obtaining the surface of the tool involves “evaporation” of the oxide non-metallic layer. This reduces the adhesion of workpiece chips to the tool surface, which leads to tool breakage and poor surface quality. The VAP surface also improves the adhesion of the coolant to the tool surface.
As for the term "Super HSS", it is not defined and each manufacturer may put different advantages into it. This can be either M50 steel or high-alloy special HSS steel.
Source: https://instruments.zp.ua/ru/reference/info/266-hss.html
What do the symbols on the drills say?
22.06.2016
A drill is a cutting tool for making blind or through holes in a solid body of material, drilling out existing holes or recesses, as well as performing other types of work. The drill acts on the material only in the axial direction! (unlike cutters that can also work with longitudinal feed).
Structurally, the drill consists of a front cutting cone (with sharp working edges), outlet spiral grooves and a shank for mounting a drilling tool - a drill, a machine tool, a hammer drill - in a chuck. Depending on the purpose, all three elements of the drill can have different shapes and designs. To an experienced craftsman, they can tell no less about the purpose and “character” of the drill than the brand markings!
Drills by type
Depending on the “reference point”, all drills can be divided into several large groups:
- by type of tool material (high-speed steel, pobedite, hardened, with a protective coating, etc.);
- for metal work;
- for wood (characterized by the presence of a thin, sharp tip for ease of initial cutting into the material);
- for fragile but hard materials (concrete, brick, etc.) - recognizable by a characteristic cutting cone with a pair of “petals” having hard surfacing;
- for drilling with shock loading - they are distinguished by protrusions and grooves on the cylindrical shank for mounting in a hammer drill chuck.
Thus, even before looking at the markings of the drill, you can accurately determine the type and purpose of the tool by external signs. And only then move on to a detailed consideration of its characteristics.
Drill marking
Very thin drills usually do not have any markings (there is simply nowhere to engrave them!). On the shanks of drills with a diameter of 3 mm or more, an alphanumeric code is applied, indicating:
- grade of material - the most common high-speed steel is designated by the letter P. Tungsten-free high-speed steels (grades EK-41, EK-42) and hard alloys (VK6, VK8, T15K6, T5K10) are also used;
- percentage of tungsten in the alloy (for example P6 - high-speed steel with 6% tungsten);
- types of alloying elements (letters: M denotes molybdenum, F – vanadium, K – cobalt, A – nitrogen, Ш – electroslag remelting);
- mass fractions of other alloying elements (also in numbers);
- Finally, the diameter symbol (may be missing) and the number next to it indicate the working size of the drill.
For example: the marking on the drill “R6M5K5 10.6” is a tool high-speed steel with 6% tungsten in the alloy, plus alloying additives of molybdenum (5%) and cobalt (5%), tool diameter 10.6 mm.
It should be noted that the larger the drill diameter, the more detailed the markings on it (may include accuracy class, manufacturer’s name, etc.).
Marking of the feather cutting tool
Strength is indicated:
- P18 is a satisfactory indicator, increased grindability, indicating a wide range of quenching temperatures.
- P 9 – characterized by increased wear resistance, a narrower range of hardening temperature indicators, and increased ductility.
- P6M5 – molybdenum is additionally added, increasing the tendency to decarbonization.
- R12F3 – have reduced grindability, used for drilling in medium mode. Added 3% vanadium.
- R6M5F3 – increased wear resistance, work at medium cutting speed, used for carbon and alloy tool steels.
- R9K5,
- R6M5K5,
- R18K5F2 – cobalt is added, which provides increased secondary hardness, heat resistance, and increased cutting conditions.
They have the designation 2304 - operational and design characteristics. Full marking 2304-4001-50-108. The indicator from 50 to 108 may vary. It indicates the possible diameter value.
Foreign markings (DIN and HSS) are deciphered a little differently - although they mean basically the same thing.
- HSS (High Speed Steel) – general marking of a group of high-speed steels;
- the following letters indicate the “specialization” of the drill: R (or without a letter designation) – drills with the lowest resistance, G – for working on carbon and alloy steels, cast iron and non-ferrous metals, E – for acid-resistant stainless steels, HSS-G TiN and HSS -G TiAlN – for processing titanium. Of course, “backward compatibility” is also true - a drill for titanium is perfect for processing both carbon and stainless steels;
- If desired, you can find out the detailed composition of the drill material using a special table.
Table of correspondence between the general chemical composition of HSS steels and their domestic analogues.
Type Domestic analogue Chemical composition, % C (carbon) Mn (manganese) Si (silicon) Cr (chromium) V (vanadium) W (tungsten) Mo (molybdenum) Co (cobalt) Ni (nickel) Tungsten HSS steels High alloy HSS steels| T1 | P18 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | — | — |
| T2 | R18F2 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | — | — |
| T4 | R18K5F2 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | 5,00 | — |
| T5 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | 8,00 | — | |
| T6 | 0,80 | — | — | 4,50 | 1,50 | 20,00 | — | 12 | — | |
| T8 | 0,75 | — | — | 4,00 | 2,00 | 14,00 | — | 5,00 | — | |
| T15 | R12F5K5 | 1,50 | — | — | 4,00 | 5,00 | 12,00 | — | 5,00 | — |
| M41 | R6M3K5F2 | 1,10 | — | — | 4,25 | 2,00 | 6,75 | 3,75 | 5,00 | — |
| M42 | 1,10 | — | — | 3,75 | 1,15 | 1,50 | 9,50 | 8,00 | — | |
| M43 | 1,20 | — | — | 3,75 | 1,60 | 2,75 | 8,00 | 8,25 | — | |
| M44 | 1,15 | — | — | 4,25 | 2,00 | 5,25 | 6,25 | 12,00 | — | |
| M46 | 1,25 | — | — | 4,00 | 3,20 | 2,00 | 8,25 | 8,25 | — | |
| M47 | R2AM9K5 | 1,10 | — | — | 3,75 | 1,25 | 1,50 | 9,50 | 5,00 | — |
| M48 | 1,42-1,52 | 0,15-0,40 | 0,15-0,40 | 3,50-4,00 | 2,75-3,25 | 9,50-10,5 | 0,15-0,40 | 8,00-10,0 | up to 0.30 | |
| M50 | 0,78-0,88 | 0,15-0,45 | 0,20-0,60 | 3,75-4,50 | 0,80-1,25 | up to 0.10 | 3,90-4,75 | — | up to 0.30 | |
| M52 | 0,85-0,95 | 0,15-0,45 | 0,20-0,60 | 3,50-4,30 | 1,65-2,25 | 0,75-1,50 | 4,00-4,90 | — | up to 0.30 | |
| M62 | 1,25-1,35 | 0,15-0,40 | 0,15-0,40 | 3,50-4,00 | 1,80-2,00 | 5,75-6,50 | 10,0-11,0 | — | up to 0.30 |
For example, drills marked M1 are more flexible and less susceptible to shock, and are suitable for general work. M2 drills are already used for high-performance machine work, due to the high degree of red resistance and preservation of the cutting edge. The M7 marking indicates flexibility and increased drill life, which is important when drilling hard sheet metal. Drills are made from M42 steel for work on tough and complex materials, and drills are made from M50 steel for portable equipment, where tool breakage due to bending is undesirable.
HSS-E drills are analogues of the domestic universal P6M5. They are suitable for working on both low-carbon steels and cast iron, as well as hard alloy and stainless steels (including acid-resistant). And the HSS-Co tool (with the addition of cobalt to the alloy) is similar to the Russian R6M5K5 drill (also containing 5% cobalt in the high-speed alloy).
HSS-G TiN is the most durable drill for working with durable titanium products. Its analogue is the domestic tool R6T5 (the last letter and number indicate a 5% titanium content, which gives high-speed steel special strength). The surface hardness of a drill with a titanium-aluminum-nitride coating (HSS-G TiAlN) is already 3000 HV, and the heat resistance is 900°C.
Finally, drills for stainless steel are marked HSS-E VAP (V2A or V4A).
Drill bits for rotary hammers
Hammer drills are often called “drills.” They have a number of characteristic differences:
- firstly, almost only fragile but very hard materials (concrete, brick, natural stone, etc.) are processed with impact loading. For this purpose, the drills have a special, reinforced design and super-hard surfacing on the cutting edges (the cutting tip with petal edges of the drills is similar in design to that of concrete drills).
- and secondly, the drills are installed in special drilling machines - rotary hammers. Their cartridges perform not only rotational, but also axial movement. This achieves the impact of the tool on the material - along with a rotational “biting” into it. Such mechanics require strong fastening of the tool in the hammer drill chuck - for this purpose, drills have a shank with longitudinal projections and grooves (unlike conventional drills with absolutely smooth cylindrical shanks). This drill fastening system is called SDS.
In accordance with this, the markings on drills are somewhat different from those for conventional drills:
- the first is the letter designation of the drill fastening system (shank design) - SDS-max or SDS-plus;
- then two numbers indicate the diameter and length of the drill (in millimeters).
For example, the “SDS-max 16*670” drill has a diameter of 16 mm and a working part length of 670 mm.
It should be noted that the diameter of the drill is always equal to an even number. Accordingly, the size range of tools will look like Ø4 mm, Ø6 mm, Ø8 mm, etc.
And back to the appearance!
At the beginning of the article, we talked about the appearance of the drill - to an experienced eye, its structural shape will immediately allow you to determine its purpose. Equally valuable information can be gleaned by assessing the color of a drill or auger:
- regular gray indicates bare, uncoated tool steel. Such a tool may be of high quality, but it is susceptible to corrosion and rapid wear (since it does not have additional heat treatment that strengthens the steel);
- A “bold” black tint indicates that the material has been treated with steam. This increases the durability of the tool, increasing its service life;
- a yellow-golden color means that the drill material was subjected to hardening (significantly increasing the strength of the tool) and then tempering (heat treatment to relieve internal stresses after hardening). Such drills have good durability, but due to the tendency of hardened steel to develop brittle cracks, the “golden” tool is sensitive to overheating and temperature changes. Therefore, during work, it is necessary to periodically cool the tool, adhering to the manufacturer’s recommendations (this is especially true for drills for rotary hammers). And under no circumstances should drills be cooled with liquid!
- bright golden color - the surface of such a drill is treated with titanium nitride. This coating reduces contact friction in the cutting area while simultaneously strengthening the metal of the tool.
It is “golden” drills and augers that are considered the “elite” among quality tools. But the price of such drills is naturally higher.
The materials were prepared by specialists from the Triv-Komplekt company.
When copying texts and other materials from the site, it is mandatory to provide a link to the site www.traiv-komplekt.ru!
Source: https://traiv-komplekt.ru/articles/chto-govoryat-oboznacheniya-na-sverlah/
HSS steel - features, grades, designations, explanation
The abbreviation HSS, made up of the initial letters of the English words High Speed Steel, denotes a whole group of steels classified as high-speed. Milling cutters, taps, and dies for thread cutting are made from steels of this type. Much less often, such material is used for the production of hacksaw blades and knives.
Alloys of the HSS category refer to high-carbon steels, some grades of which may contain significant amounts of tungsten. The hardness of a tool made from this type of steel can be in the range of 62–64 units on the HRC scale.
End mill made of HSS-Co8 steel is capable of processing material with a tensile strength of up to 1100N/mm2
Tools made from HSS steels, when compared with carbide steels, are more affordable and have higher strength, which allows them to be successfully used for interrupted cutting. Meanwhile, processing with their help is allowed at lower cutting speeds when compared with carbide drills.
The composition of high-speed steels, which foreign manufacturers call HSS alloys, has been constantly improved. So, from the end of the 19th century, a significant amount of tungsten began to be added to such steels (up to 18%), and from 1912 cobalt began to appear in these alloys. It was only in 1930 that molybdenum was included in HSS steels.
Main characteristics and brands
Depending on their composition, HSS steels are divided into three categories:
- with a high content of tungsten (T);
- molybdenum (M);
- highly doped group.
Chemical composition of tungsten HSS steels
Due to the high cost and shortage of tungsten, steels with a high tungsten content are used quite rarely in our time. The most common steels in this group are the general purpose alloy T1 and the steel alloy T15 containing vanadium and cobalt. The latter is used, in particular, for the manufacture of products that must be highly resistant to wear and high temperatures.
Chemical composition of molybdenum HSS steels
More common are HSS molybdenum steels, which may also contain tungsten and cobalt. High-speed steels of the molybdenum group, which contain a significant amount of vanadium and carbon, are resistant to abrasive wear.
For the manufacture of products that must maintain high hardness even at high temperatures, molybdenum steel alloys are used, starting from grade M41.
In the production of tools operated in cold conditions and with high impact strength, steel alloys of the molybdenum group are also used, subjecting them to special heat treatment.
Chemical composition of high alloy HSS steels
When choosing tools from HSS steels of the molybdenum group, you should take into account the characteristics of individual grades of such steel alloys. M1
HSS drills for a wide range of applications are made from steel of this grade. HSS drills made from M1 alloy are more flexible and less susceptible to shock loads, but their red-hardness level is lower than that of tools made from M2 steel.
M2
This is the most common material from which tools for various purposes are made. Products made from HSS steel of this grade, used for high-performance machine work, are distinguished by high red resistance; the parameters of their cutting edges are maintained longer than those of tools made from high-speed steels of other brands.
M7
This alloy is used to produce powerful drills, which require not only high flexibility, but also exceptional reliability. Using HSS metal drills, made from this alloy, holes are made in hard and thick sheet materials.
M50
This is the material used to make drills that work with portable equipment. Under these conditions, tool breakage due to significant bending is a fairly pressing problem. An HSS drill made from M50 steel alloy does not have the same red resistance as tools made from other grades of high-speed steel.
M35
This alloy, which is also designated as HSSE, due to the increased cobalt content, has higher red resistance than M2 high-speed steel. Meanwhile, the increased content of this element in the composition of HSSE steel reduces its resistance to impact loads.
M42
This is a steel that contains the maximum amount of cobalt, which is why it is often called Super Cobalt. Tools made from HSS steel of this grade are distinguished not only by their high red resistance, but also by their exceptional abrasion resistance. Thanks to these characteristics, steel of this grade is successfully used for the production of tools with which it is necessary to process viscous and complex materials.
tungsten in the composition of HSS steels makes it possible to provide products made from them with red resistance.
This quality lies in the fact that the cutting edge of the tool retains its hardness even at a red heat temperature of 530°. High-speed steel alloys containing cobalt (HSS Co) have an even higher red-hardness (as well as increased wear resistance). The cutting edges of HSS Co grade drills are able to maintain their hardness at higher temperatures.
Types of high-speed HSS steels
The invention of high-speed steel at the beginning of the twentieth century was a breakthrough in the development of mechanical engineering. The new material influenced the invention of high-speed machines and high-power automatic machines, and also contributed to a sharp jump in productivity in machine shops. Despite the fact that HSS steel has a rather complex composition, it is actively used for the production of tools of increased strength.
What is HSS steel
The abbreviation HSS is derived from the English High Speed Steel - “high-speed steel”. It is used in the production of various tools for working with metal products. For production, the classical method of casting into ingots followed by rolling and forging is used. The powder method is also used - spraying a stream of liquid steel with nitrogen.
HSS alloys belong to the high carbon group, some grades of which contain a certain amount of tungsten. The hardness of tools made from this material corresponds to 62-64 units on the HRC scale.
Products made from high-speed steel have increased strength and are in an affordable price segment.
Area of application of high-speed steels
The composition of the material determines the application and performance characteristics. Tools made from this metal can withstand long-term use.
HSS steel is used:
- for the production of drills with complex shapes and designs obtained by casting;
- in the production of cutting edges of cutters to increase wear resistance;
- for forming cutting tool tips;
- for the manufacture of cutters, countersinks, taps, dies, knives or saw blades.
Types of HSS steels
HSS steels come in three categories:
- tungsten (T1-T15);
- molybdenum (M1-M36);
- highly alloyed (M41-M62).
Steels belonging to the tungsten group are not popular nowadays due to the high cost of tungsten.
The most commonly used grade is T1 and the alloy with the addition of cobalt and vanadium T15. T15 steel is used to produce tools that are needed to work at high temperatures and increased wear.
Tungsten
The tungsten group is known for four types of steel:
- T1 (analogue - P18). It has high strength, wear resistance and sandability. Used for drills and other tools, which are most often used for processing alloy and carbon steels.
- T2 (analogue - R18F2). In this alloy, the vanadium content reaches 2%. Semi-finish and finishing drills are made from it for processing medium-alloy steels.
- T3 (analogue - R18K5F2). The alloy contains: tungsten – 18%, cobalt – 5%, vanadium – 2%. Tools made from this alloy are distinguished by increased wear resistance and hardness, but have low grindability. Drills are most often used to work with workpieces made of corrosion-resistant, high-strength and heat-resistant alloys.
- T15 (analogue - R12F5K5). Contains: tungsten – 12%, cobalt – 5%, vanadium – 5%. The tools have high strength, wear resistance and toughness. They are mainly used for drilling difficult-to-cut materials.
tungsten gives the manufactured tool red resistance, which allows it to maintain the hardness and sharpness of the cutting edge at elevated temperatures.
Molybdenum
The molybdenum group is more widespread. The alloys also contain cobalt and tungsten.
Steels containing components such as carbon and vanadium exhibit resistance to wear during grinding.
Products that maintain increased hardness during operation at high temperatures are made from molybdenum steels grade M41 and higher. Tools with high impact strength at low temperatures are made from molybdenum alloys followed by heat treatment.
- M1. molybdenum - 8%. Used for general purpose tools. The drills are flexible and resistant to loads, but the red resistance is significantly lower than that of other brands.
- M2 (analogue - P6M5). Alloy composition: tungsten – 6%, molybdenum – 5%. Endowed with sufficient strength, hardness and heat resistance. During operation, the cutting edges of the tool are preserved longer.
- M3 (analogue - R6M5F3). Contains 3% vanadium. Tools made from this steel have low wear during grinding.
- M7. Components: tungsten – 1.75%, vanadium – 2%, molybdenum – 8.75%. The alloy is used for the manufacture of drills, which are needed for working with thick sheets and hard metals.
- M35 (analogue - R6M5K5). The composition contains 5% cobalt, molybdenum, tungsten, as well as in small quantities silicon, nickel and manganese. The advantage of the alloy is its toughness, good grindability, heat resistance and wear resistance. Drills are used when processing products made of stainless and improved alloy steels under conditions of high heating of the cutting edge.
High alloy
Highly alloyed alloys belong to the molybdenum group. Steels that have undergone special heat treatment are used to produce tools with increased toughness and the ability to operate in cold conditions.
- M74 (analogue - R2AM9K5). The composition includes: molybdenum – 9%, cobalt – 4.7-5.2%. It is characterized by an increased tendency to loss of carbon, overheating during the hardening process and reduced grindability. Tools made from this alloy are used for workpieces made of stainless and improved alloy steels.
- M42. alloy: cobalt – 8%, molybdenum – 9.5%. The drills are resistant to abrasion. The tools are used for processing complex and tough metals.
Characteristics of high-speed steels
When listing the characteristics, it is necessary to take into account that the created material is necessary for the operation of cutting devices at high levels of friction that arise during the cutting process. High-speed steels have increased hardness and can be used in work requiring high speeds.
Hot hardness
When using cutting devices during operation, heat is constantly released, and about 80% is spent on heating the tool. The temperature of the cutting edge rises and the material is tempered, which entails a decrease in its hardness. Nevertheless, high-speed steel retains its performance even when heated to 500-600°C.
Red fastness
An indicator that takes into account the time period during which steel can withstand elevated temperatures without changing its performance characteristics. An overestimated friction index leads to heating of the metal, which causes changes in the crystal lattice. As a result, some properties of high-speed steel change significantly.
Fracture Resistance
The material used for the manufacture of cutting tools must have high mechanical properties - resistance to brittle fracture. The high strength of the alloy provides the cutting device with resistance to high force, feed and depth of cut, which in turn leads to increased productivity of the process.
Features of heat treatment
The result of high-temperature processing of high-speed steels is a change in the structure of the material to obtain certain physical and mechanical properties required when working with this tool.
Annealing
HSS steel after the rolling and forging process acquires increased hardness and internal stress. In this regard, the workpieces are preliminarily annealed. Annealing relieves the internal stress of the material, improves machinability and prepares it for hardening.
The annealing process occurs at a temperature of about 850-900°C. However, one should be wary of excessively increasing the temperature and duration of exposure, because this may cause the steel to become more hard. Due to the reduced thermal conductivity of the alloy, heating is carried out slowly and evenly.
The products are loaded into the oven at a temperature of 200-300oC, while subsequent heating is increased at a rate of 150-200o/hour. The process ends with slow cooling: first in an oven to 650 ° C, and then to room temperature in the open air.
To protect against decarburization, annealing is carried out in closed boxes with a neutral environment.
Machine-building plants subject a small number of workpieces to isothermal annealing. They are heated to 880-900oC for a short time, and then transferred to an oven with a temperature not higher than 720-730oC for 2-3 hours. To protect against the appearance of excessive internal stresses, the workpieces are cooled in an oven to 400-450°C and then left in the open air.
Conventional annealing takes longer than the isothermal process. Subsequently, the workpieces undergo mechanical processing, and then the tool undergoes the final heat treatment process - hardening and tempering.
Hardening
Tools made of high-speed steel are hardened at temperatures above 1300°C. After the hardening process, repeated tempering occurs at 550-560°C. This temperature is necessary to dissolve a large number of carbides in the austenite to obtain highly alloyed austenite.
With further cooling, highly alloyed martensite is obtained, which contains large amounts of tungsten, vanadium and chromium. Martensite does not disintegrate when heated to 600°C, which gives high-speed steel red-hardness.
To obtain high red-hardness values, the temperature during hardening must be very high. However, there is a limit, when exceeded, rapid grain growth begins in high-speed steel and melting occurs.
Vacation
Hardened high-speed steel must undergo a tempering process. At a temperature of 550-560°C, a multiple process is carried out at intervals of 1 hour. The purpose of tempering is to transform austenite into martensite. High speed steel goes through two internal processes:
- When heated and subsequently tempered, ground carbide is released from the retained austenite. As a result, the alloying of austenite is reduced, which facilitates easy transformation into martensite.
- During cooling at 100-200°C, martensite is obtained. This also relieves the internal stress that arose during hardening.
Nowadays, factories most often use the process of accelerated tempering of steel, which takes place at elevated temperatures.
Improving the characteristics of products made from HSS steels
To impart hardness to the material, resistance to wear and resistance to corrosion, the surface of the tools is subjected to additional processing. These methods include:
- Nitriding. Saturation of the surface layer with nitrogen is carried out in a gas environment, which consists of 80% nitrogen and 20% ammonia or 100% ammonia. The technological process lasts from 10 to 40 minutes at a temperature of 500-600°C and leads to strengthening of the surface shell.
- Cyanidation. Saturation is carried out in a liquid or gaseous medium consisting of a chemical element - zinc. The high-temperature cyanidation process lasts from 5 to 45 minutes at a temperature of 800-900oC. The low-temperature process occurs at 500-600°C and provides wear resistance and high hardness to the tool.
- Sulfidation. Saturation of the surfaces of steel products with sulfur is carried out at 550-600°C by heating in sulfur-nitrogen salts for 2-3 hours. As a result of the process, the wear resistance of steel products increases.
The essence of chemical-thermal treatment is the penetration of various chemical elements into the atomic crystal lattice of iron when heating steel parts in an environment saturated with the necessary elements.
High-speed alloy steels are intended for the production of metal-cutting tools, which are used when working at high speeds. HSS alloys are distinguished by their ability to maintain wear resistance and resistance to fracture at elevated temperatures. The addition of molybdenum, tungsten, cobalt and vanadium to the steel composition provides red resistance and hot hardness.
Source: https://martensit.ru/stal/hss-stal/
an engineer will help - Differences between HSS and carbide drills
In this article we will look at the differences between drills made from different materials: HSS and carbide drills. Let's consider what materials can be processed with these drills, what subtleties there are when sharpening, cutting modes, and also compare the quality of the surface that has been processed.
So let's start with the HSS drill.
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HSS drill
HSS (High Speed Steel) is a group that includes steels that are high-speed. Typically, cutting tools are made from these steels. In our case, drills. The steel of this group is high-carbon. Hardness reaches 62-64 HRC.
Advantages over carbide alloys - high-speed steel has greater strength and lower cost.
However, the cutting speed is slower than that of carbide drills.
Drills can be made from tungsten, molybdenum and high-alloy high-speed steels.
Now we will look at the symbols of drills made of high-speed steels and figure out where the drills are applicable and what quality the processed surface will have.
HSS-R - such a drill will have low durability.
HSS-G - This drill has a CBN (cubic boron nitride) polished cutting part. It features increased durability and low radial runout.
HSS-E - cobalt is added to the steel of this drill. Suitable for working with difficult materials.
HSS-G TiN is a drill whose surface is coated with titanium nitride. Which, by the way, serves to increase surface strength.
HSS-G TiAlN is a drill whose surface is coated with titanium-aluminum-nitride.
HSS-E VAP - this tool is useful if you need to process stainless steel.
Drill prices vary. For example, an HSS Co-5 drill can be purchased at a cost of 300 rubles. And purchasing core drills can reduce your budget by 1 thousand rubles. and more.
Carbide drill
The use of carbide drills for processing glass, marble, granite, cast iron, and plastic is the main purpose of the tool. I should immediately note that carbide drills have a high manufacturing cost. That is why they are not very common. Typically, drills do not have high strength and rigidity. They have a tendency to chip.
Such drills are ideal for processing surfaces based on heat-resistant and high-strength metals.
The quality of the processed surface is very high.
The angle of inclination of the front part of the drill is 6-8 degrees. The helical groove has an angle of 20 degrees. If deep holes are drilled, the screw grooves should have an inclination angle of 45 - 60 degrees.
The cost of a drill can also vary, depending on the manufacturer, as well as on the quality of the tool. So, you can buy a carbide drill for a reasonable price, within 400 rubles, or you can buy a drill for 1.5 thousand rubles.
As you and I have seen, drills made from different materials have their own advantages and disadvantages, and at the same time they have completely different costs. Therefore, you should be very careful when choosing drills for workshops and industries.
Source: http://engcrafts.com/item/224
What is HSS steel? Types and analogues of HSS
HSS (High Speed Steel) - denotes a group of high-speed steels, translated as steel for working at high speeds. HSS steel is used to produce a wide range of different metal-cutting tools. This includes twist drills, core drills, step drills, cutters, countersinks, taps, dies, knives and saw blades.
High-speed steel is produced in the classical way - by casting steel into ingots, then rolling and forging, as well as by powder metallurgy - here a jet of liquid steel is sprayed with nitrogen.
HSS steels are considered high carbon, typically HSS steel tools have a hardness of 62-64 HRC. The main advantage in comparison with carbide tools is the durability and lower price of the tools.
HSS steel performs well in interrupted cutting; the use of HSS may be limited by low cutting speeds compared to carbide alloys.
Characteristics of HSS steels
HSS steels are divided into three main groups:
- Tungsten (T);
- Molybdenum (M);
- High-alloy high-speed steels.
Tungsten steels are now practically not used due to the high price of tungsten and its shortage. The most commonly used steels are T1 general purpose steels and T15 vanadium-cobalt steels. T15 is used for tools used at high temperatures and increased wear.
In molybdenum group steels, the main alloying element is molybdenum, but some of them may contain equal or even greater amounts of tungsten and cobalt. Steels with high vanadium and carbon content are very resistant to abrasive wear.
The type of steel from M41 is characterized by high hardness when working at high temperatures, or the term used is red resistance. Molybdenum steels are also used in the production of tools used in “cold” conditions - rolling dies, cutting dies.
In such cases, HSS steels are hardened to lower temperatures to increase toughness.
Table of common chemical compositions of HSS steels. Russian analogues.
| Type | Russian analogue | Chemical composition, % | ||||||||
| C | Mn | Si | Cr | V | W | Mo | Co | Ni | ||
| Tungsten HSS steels | ||||||||||
| T1 | P18 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | — | — |
| T2 | R18F2 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | — | — |
| T4 | R18K5F2 | 0,75 | — | — | 4,00 | 1,00 | 18,00 | — | 5,00 | — |
| T5 | 0,80 | — | — | 4,00 | 2,00 | 18,00 | — | 8,00 | — | |
| T6 | 0,80 | — | — | 4,50 | 1,50 | 20,00 | — | 12,00 | — | |
| T8 | 0,75 | — | — | 4,00 | 2,00 | 14,00 | — | 5,00 | — | |
| T15 | R12F5K5 | 1,50 | — | — | 4,00 | 5,00 | 12,00 | — | 5,00 | — |
| Molybdenum HSS steels | ||||||||||
| M1 | 0,80 | — | — | 4,00 | 1,00 | 1,50 | 8,00 | — | — | |
| M2 | R6M5 | 0,85 | — | — | 4,00 | 2,00 | 6,00 | 5,00 | — | — |
| M3 | R6M5F3 | 1,20 | — | — | 4,00 | 3,00 | 6,00 | 5,00 | — | — |
| M4 | 1,30 | — | — | 4,00 | 4,00 | 5,50 | 4,50 | — | — | |
| M6 | 0,80 | — | — | 4,00 | 2,00 | 4,00 | 5,00 | — | — | |
| M7 | 1,00 | — | — | 4,00 | 2,00 | 1,75 | 8,75 | — | — | |
| M10 | 0,85-1,00 | — | — | 4,00 | 2,00 | — | 8,00 | — | — | |
| M30 | 0,80 | — | — | 4,00 | 1,25 | 2,00 | 8,00 | — | — | |
| M33 | 0,90 | — | — | 4,00 | 1,15 | 1,50 | 9,50 | — | — | |
| M34 | 0,90 | — | — | 4,00 | 2,00 | 2,00 | 8,00 | — | — | |
| M35 | R6M5K5 | 0,82-0,88 | 0,15-0,40 | 0,20-0,45 | 3,75-4,50 | 1,75-2,20 | 5,5-6,75 | 5,00 | 4,5-5,5 | up to 0.30 |
| M36 | 0,80 | — | — | 4,00 | 2,00 | 6,00 | 5,00 | — | — | |
| High alloy HSS steels | ||||||||||
| M41 | R6M3K5F2 | 1,10 | — | — | 4,25 | 2,00 | 6,75 | 3,75 | 5,00 | — |
| M42 | 1,10 | — | — | 3,75 | 1,15 | 1,50 | 9,50 | 8,00 | — | |
| M43 | 1,20 | — | — | 3,75 | 1,60 | 2,75 | 8,00 | 8,25 | — | |
| M44 | 1,15 | — | — | 4,25 | 2,00 | 5,25 | 6,25 | 12,00 | — | |
| M46 | 1,25 | — | — | 4,00 | 3,20 | 2,00 | 8,25 | 8,25 | — | |
| M47 | R2AM9K5 | 1,10 | — | — | 3,75 | 1,25 | 1,50 | 9,5 | 5,00 | — |
| M48 | 1,42-1,52 | 0,15-0,40 | 0,15-0,40 | 3,50-4,00 | 2,75-3,25 | 9,50-10,5 | 0,15-0,40 | 8,00-10,0 | up to 0.30 | |
| M50 | 0,78-0,88 | 0,15-0,45 | 0,20-0,60 | 3,75-4,50 | 0,80-1,25 | up to 0.10 | 3,90-4,75 | — | up to 0.30 | |
| M52 | 0,85-0,95 | 0,15-0,45 | 0,20-0,60 | 3,50-4,30 | 1,65-2,25 | 0,75-1,50 | 4,00-4,90 | — | up to 0.30 | |
| M62 | 1,25-1,35 | 0,15-0,40 | 0,15-0,40 | 3,50-4,00 | 1,80-2,00 | 5,75-6,50 | 10,0-11,0 | — | up to 0.30 |
A tool containing tungsten (W) will have very useful cutting properties and such qualities as red resistance. This allows the tools to maintain sharp hardness and a sharp cutting edge at red-hot temperatures (up to 530°C). Cobalt (K) further increases red-hardness and wear resistance.
M1. Used for the production of drills for various ranges of applications. M1 steel has less red resistance than M2 steel, but is less susceptible to impacts and is more flexible.
M2. The most common material for the production of tools is HSS steel. M2 retains its cutting edge for a long time and has good red resistance, unlike other HSS steels with lower tungsten content. It is usually used for the manufacture of tools for high-performance machine work, for example in drilling machines.
M7. Used for heavy construction drills when drilling hard sheet metal. This HSS steel is used where flexibility and increased service life are required.
M50. Used to make drills that are used for drilling on portable equipment. Does not have the same red resistance as other tungsten HSS steels
M35. M35 steel has a higher red resistance compared to M2. At the same time, cobalt slightly reduces the resistance to impact loads.
M42. M42 “Super Cobalt” steel has excellent abrasion resistance and high red-hardness. Used when working on viscous and complex materials.
Legend
The designation of foreign manufacturers does not fully disclose the chemical composition of the HSS steel from which the products are made. A particular tool is assigned a specific task, which is described in the catalog.
Other details can be found out by determining the chemical composition, this can be done using a portable metal analyzer, or by testing the products experimentally. Such marking, of course, may be convenient for an unscrupulous manufacturer who may indicate HSS steel on the drill, but it will not meet the necessary requirements.
Below are the main markings that characterize the material from which the tool is made and its scope of application.
HSS-R (or simply HSS) is a designation on products that have undergone roller rolling and heat treatment. Such products have the lowest durability.
HSS-G - designation on products that are made of HSS steels, the cutting part is ground with CBN (cubic boron nitride). The products have increased durability and less radial runout. HSS-G tools are the most common and are used to solve standard problems.
HSS-E – cobalt is added to products made from HSS steel type M35. Used when working on viscous and complex materials. There are also such markings as HSS Co 5 and HSS Co 8, which indicate cobalt content of 5 and 8%
HSS-G TiN - this marking indicates the deposition of titanium nitride. This coating allows increasing surface hardness by approximately 2300 HV and heat resistance up to 600°C.
HSS-G TiAlN - surface of products coated with titanium-aluminum-nitride. This coating allows increasing surface hardness by approximately 3000 HV and heat resistance up to 900°C.
HSS-E VAP - VAP - used for processing stainless steels (V2A and V4A). It is obtained by “evaporating” the oxide non-metallic layer. This reduces the adhesion of workpiece chips to the tool surface, which can lead to product failure. As a result, the surface quality is improved and, thanks to VAP, the adhesion of the coolant to the tool surface is improved.
| Characteristics of heat resistance of carbon and red resistance of high-speed tool steels | |||
| steel grade | Temperature, °C | Exposure time, hour | Hardness, HRC e |
| U7, U8, U10, U12 | 150—160 | 1 | 63 |
| P9 | 580 | 4 | |
| U7, U8, U10, U12 | 200—220 | 1 | 59 |
| R6M5, R6M5K5, R9, R9M4K8, R18 | 620—630 | 4 |
Source: https://kornor.ru/blog/ugolok-pokupatelya/chto-takoe-hss-stal-vidy-i-analogi-hss.html
