What is carbide

How to choose the right grade of carbide

How to choose the right grade of carbide. 4.73/5 (94.55%) lost 11

Metal-ceramic hard alloys are divided into two groups:

— Titanium-tungsten alloys “TK” (they are used to process steel materials and products);

— Tungsten alloys “VK” (with their help, non-ferrous metals and alloys, cast iron materials and non-metallic products are processed).

In turn, these two groups are divided into grades of hard alloys. They have their own distinctive features (properties), which determine the conditions and areas of use of this brand. The properties of each grade of hard alloys are designed so that the manufactured products can support production in any industry.

It is very important to choose the right grade of hard alloy for each type of work performed. This factor is very important and is one of the main ones; it cannot be neglected; the speed and quality of the work performed depends on it.

— Physico-mechanical and operational properties of hard alloys;
— Characteristics of the processed material;

— Technical conditions of processing and its type;
— The nature of the requirements for processing accuracy and cleanliness of processed surfaces;

— The state of the machine and its kinematic and dynamic data.

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Table of physical and mechanical properties of hard alloys and its chemical composition.

Alloy (group)	Alloy grade	Theoretical composition of the alloy (without taking into account the presence of impurities), %	Physical and mechanical properties
Wolfram carbide	cobalt	titanium carbide	bending strength, kg/mm2 not less	specific gravity	Rockwell hardness, scale A, not less
Tungsten	VK2	98	2	—	100	15,0-15,4	90,0
VK3	97	3	—	100	14,9-15,3	89,0
VK6	94	6	—	120	14,6-15,0	88,0
VK8	92	8	—	130	14,4-14,8	87,5
VK11	89	11	—	150	14,0-14,4	86,0
Titanium-tungsten	T5K10	85	9	6	115	12,3-13,2	88,5
T14K8	78	8	14	115	11,2-12,0	89,5
T15K6	79	6	15	110	11,0-11,7	90
Т15К6Т	79	6	15	110	11,0-11,7	91
T30K4	66	4	30	90	9,5-9,8	92,0
T60K6	34	6	60	75	6,5-7,0	90,0

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Tungsten grades of hard alloys:

VK2 is the hardest, wear-resistant and heat-resistant of all tungsten group alloys;

VK3 – high wear resistance and hardness, but slightly lower than that of the VK2 alloy;

VK6 – lower wear resistance and hardness than alloy VK3, with greater operational strength;

VK8 – high operational strength and resistance to shock, vibration and chipping, with less wear resistance and hardness than the VK6 alloy;

VK11 is the most durable of all the above tungsten hard alloys. Lowest hardness and wear resistance. It is used when processing special hard-to-cut materials.

Titanium-tungsten grades of hard alloys:

T5K10 – the highest operational strength for titanium-tungsten alloys. Less hard and wear-resistant than T14K8 alloy;

T14K8 - Greater hardness, wear resistance and heat resistance than the T5K10 alloy, with slightly lower operational strength;

T15K6 – greater hardness, wear resistance and heat resistance than the T14K8 alloy, with lower operational strength;

T15K6T – greater hardness and wear resistance than the T15K6 alloy, with slightly reduced operational strength;

T30K4 – high hardness, wear resistance and heat resistance, with significantly reduced operational strength;

T60L6 is the most wear-resistant and heat-resistant of all titanium-tungsten group alloys, with the lowest operational strength.

Below you can find a table of recommendations for choosing grades of hard alloys depending on the type, nature and processing conditions, as well as on the material being processed. However, there may be cases in which, due to the specific nature of the operation, application conditions or material being processed, this table will not be sufficient.

Table of carbide grades

Table for selecting grades of hard alloys depending on the type, processing conditions, nature and material being processed.

Characteristics of processing conditions	Rigidity of the “Machine-part-tool” system	Comparative assessment of alloys in terms of productivity	Recommended carbide grades for machining
Carbon-disto-alloy-steel	Special difficult-to-process steel	Hardened steel	Cast ironNV≤240	High-hardness cast iron NV = 400-700	Non-ferrous metals and their alloys	Non-metallic materials
TURNING OF EXTERNAL AND END SURFACES AND BORING HOLES
Rough turning of forgings, stampings and castings on crust and scale with an uneven cut section and intermittent cutting (with impacts)	Promoted.	Highest	T5K10	VK8	—	VK6	—	VK6	—
Normal	Average	VK8	VK11	—	VK6	—	VK6	—
Disadvantage	Demoted.	VK11	—	—	VK8	—	VK8	—
Rough turning along the skin with an uneven cut section and continuous cutting	Promoted.	Highest	T15K6	T5K10	—	VK6	VK6	VK6	VK2VK3
Normal	Average	T14K8	VK8	—	VK6	VK6	VK6	VK6
Disadvantage	Demoted.	T5K10	VK11	—	VK8	VK8	VK8	VK8
Semi-finish and finish turning with interrupted cutting	Promoted.	Highest	T15K6	T5K10	T14K8	VK6	—	VK6	VK2VK2
Normal	Average	T14K8	VK8	T5K10	VK6	—	VK6	VK6
Disadvantage	Demoted.	T5K10	VK11	VK8	VK8	—	VK6	VK6
Semi-finish and fine turning with continuous cutting	Promoted.	Highest	T30K4	T15K6	T15K6	VK2VK3	VK2	VK2VK3	VK2VK3
Normal	Average	Т15К6Т	T14K8	T14K8	VK6	VK6	VK3	VK2VK3
Disadvantage	Demoted.	T15K10	T5K10	T5K10	VK6	VK6	VK6	VK6
Fine turning (diamond type)	Promoted.	Highest	T60K6	—	T30K4	VK2VK3	VK2	VK2VK3	VK3
Normal	Average	T30K4	—	Т15К6Т	VK2VK3	VK2	VK2VK3	VK2VK3
Disadvantage	Demoted.	Т15К6Т	—	T15L6	VK6	VK6	VK6	VK6
MILLING
Rough milling	Promoted.	Highest	T15K6	T5K10	—	VK6	VK6	VK2VK3	VK2VK3
Normal	Average	T14K8	VK8	—	VK6	VK6	VK2VK3	VK2VK3
Disadvantage	Demoted.	T5K10	VK8	—	VK8	VK8	VK6	VK6
Finish milling	Promoted.	Highest	T30K4	T15K6	T30K4	VK2VK3	VK2VK3	VK2VK3	VK2VK3
Normal	Average	T15K6	T14K8	T15K6	VK6	VK6	VK2VK3	VK2VK3
Disadvantage	Demoted.	T14K8	T5K10	T14K8	VK6	VK6	VK6	VK6
DRILLING HOLES
Solid drilling	Promoted.	Highest	T14K8	VK8	VK6	VK6	—	VK2VK3	VK2VK3
Normal	Average	T5K10	VK8	VK8	VK6	—	VK6	VK6
Disadvantage	Demoted.	VK8	—	—	VK8	—	VK8	VK8
Reaming	Promoted.	Highest	T15K6	T5K10	VK2VK3	VK2VK3	—	VK2VK3	VK2VK3
Normal	Average	T15K6	VK6	VK6	VK6	—	VK6	VK6
Disadvantage	Demoted.	T14K8	VK8	VK8	VK8	—	VK6	VK6
COUNTER COUNTERING HOLES
Rough countersinking	Promoted.	Highest	T14K8	T5K10	—	VK2VK3	VK2VK3	VK2VK3	VK2VK3
Normal	Average	T5K10	VK6	—	VK6	VK6	VK6	VK6
Disadvantage	Demoted.	VK8	VK8	—	VK8	VK8	VK8	VK6
Finish countersinking	Promoted.	Highest	T30K4	T15K6	T15K6	VK2VK3	—	VK2VK3	VK2VK3
Normal	Average	T15K6	T14K8	T14K8	VK6	—	VK6	VK6
Disadvantage	Demoted.	T15K6	T5K10	T14K8	VK6	—	VK6	VK6
REAMING HOLES
Reaming holes	Promoted.	Highest	T60K6	T30K4	T30K4	VK2VK3	—	VK2VK3	VK2VK3
Normal	Average	T30K4	Т15К6Т	Т15К6Т	VK6	—	VK6	VK6
Disadvantage	Demoted.	Т15К6Т	T15K6	T15K6	VK6	—	VK6	VK6

Source: https://mechanicinfo.ru/kak-vybrat-nuzhnuyu-marku-tverdogo-splava/

Hard alloys

Hard alloys include a separate group of compounds that are capable of maintaining their properties at sufficiently high temperatures and prolonged mechanical action on other materials. Even when the temperature reaches 1150 °C, the hard alloy retains all physical and mechanical properties. They are made from refractory metals with increased hardness.

Hard alloys

Characteristics and markings

A characteristic feature of obtaining such compounds is the use of specific technological processes. This process is special pressing. It is carried out by thoroughly mixing metal powders with the addition of powdered cobalt. Then a process called thermal sintering is carried out.

High-temperature fusion of a special charge is used. This mixture consists of a large number of components. It includes: tungsten, cobalt, broken glass, coke, alloying additives, for example, chromium.

To identify the entire variety of such compounds, GOST has established the following marking of hard alloys. Hard alloy grades consist of capital letters of the Russian alphabet and a set of numbers. Each letter carries its own meaning.

Examples include the following brands:

• VK2 - the first letter “B” indicates the presence of tungsten in the composition, the second determines the presence of cobalt. The number indicates the percentage of each metal. In our case, this 2% is cobalt, the basis is tungsten. Its content reaches 98%;
• VK6M is also a tungsten-cobalt hard slav. The number six represents the percentage of cobalt available. The remaining 94 percent is tungsten. “M” specifies the scope of application. It indicates the use of this material in the production of tools for processing metals that are difficult, almost impossible to process (for example, stainless steel).
• VK8 alloy has the composition: 92% steel, 8% tungsten.
• T5K10 - this marking indicates that this sample includes three elements: tungsten, titanium, cobalt. It contains: tungsten - 85%, titanium - 5%, cobalt -10%.
• T14K8 - has the same composition of elements. But their percentages differ: tungsten is 78%, titanium is 14%, cobalt is 8%.
• TT7K12 – its composition includes four main metals: tungsten, titanium, tantalum, cobalt. Tungsten - 81%, cobalt - 12%, the rest is an alloy of the two remaining metals.
• Modern technologies have made it possible to develop unique compounds with the addition of elements such as nickel and molybdenum. For example, KTS-1 or TN-20.

Carbide alloy VK8

The international ISO classification divides all domestic alloys and foreign analogues into areas of application. This classification is indicated by letters of the Latin alphabet, which indicate the material being processed:

• H – used for hardened steel;
• K – for all types of cast iron;
• M – used for stainless steel;
• N – used for metals belonging to the category of non-ferrous metals or their compounds;
• P – a separate category of castings in which so-called drain chips are formed;
• S – for metals and compounds with increased heat-resistant characteristics.

Classification

The variety of such materials requires a clear division according to their characteristic features. Classification of hard alloys is made according to the following criteria:

• composition of chemical elements (name, percentage);
• on production technology;
• Areas of use.

Based on the chemical elements present, they are divided into the following categories:

• tungsten-cobalt (marking VK);
• titanium-tungsten-cobalt (TC);
• titanium-tantalum-tungsten-cobalt (TTK).

According to the production technologies used, they are divided into: sintered, cast, and powdered. Sintered, composed of carbides. Divided into three groups:

• single-carbide (tungsten carbide);
• two-carbide (including carbides of two metals: titanium and tungsten);
• tricarbide (welded from three elements).

Based on the percentage content of each element, they are divided into the following groups.

The first includes materials consisting of tungsten carbide and cobalt. They are designated VK. This large group includes alloys: VK4, VK3M, VK6M. The hard alloy VK8 and VK3 is very popular. VK3 stands for the same as all tungsten alloys.

The second combines titanium-tungsten alloys. It has the abbreviation TK. These include: T5K10, T14K8.

The third includes all titanium tantalum tungsten alloys. Designated TTC. For example, TT7K12 and others.

The fourth combines materials that have a wear-resistant coating. They are designated by the abbreviation VP. It includes: VP3115, VP3325. Each of them is based on a well-known alloy. For example, VPZ115 has a base of VK6.

Tungsten-containing hard alloys

They are marked as follows - VK6, VKZM, VK6M, VK8. The main area of ​​application is the production of cutting tools. Alloy VK8 is used for the manufacture of cutters.

Set of tips VK6

It allows you to process cast iron. Used for the production of tools capable of so-called chip-free processing of materials.

Titanium-tungsten-containing hard alloys

Tools for high-speed processing of various types of steel are made from grades T5K10, T14K8, T15K6. They are used to process metals and various compounds with increased hardness and heat resistance.

The most typical example of such a tool are various types of cutters and drill cores.

Characteristics of hard alloys

Characteristics determine their properties and scope of application. These include:

• name and percentage of chemical elements;
• physical and mechanical properties;
• features of technological production processes;

The chemical composition and percentage of main elements are determined according to GOST tables.

Production of hard alloys

Physical and mechanical characteristics include:

• permissible strength, which is checked by bending (varies from 1200 MPa VK2, to 2150 MPa for alloy VK25);
• hardness (increases from 89.5HRA - VK3, reaches 91 HRA - TT20K9);
• density (this indicator ranges from 14.9 g/cm3 to 15.2 g/cm3);
• realized thermal conductivity - about 51 W/(m×°C);
• heat resistance;
• corrosion resistance.

The given list of characteristics allows you to determine the scope of use.

Areas of use

They are used to make accessories for metal-cutting machines and drilling equipment.

The list of main areas of use is as follows:

• manufacture drills, cutters, cutters and other metal-cutting tools;
• individual parts of the measuring instrument;
• production of special stamps, various stamps;
• cutting tools;
• individual elements of machines for drawing and rolling;
• tools for mining equipment;
• wear-resistant bearing elements;
• spraying on steel bearing housings;
• equipment for ore processing factories;
• spraying on the surface of parts made of softer materials. This can significantly improve hardness, heat resistance, and corrosion resistance.

Source: https://stankiexpert.ru/spravochnik/materialovedenie/tverdye-splavy.html

Hard alloy. Brands, characteristics, application. Carbide tools:

Hard metals and alloys are wear-resistant materials that can maintain their characteristics at elevated temperatures (900-1100 degrees). They have been known to man for more than a hundred years.

general characteristics

Hard alloys are made primarily on the basis of chromium, tantalum, titanium, tungsten with the addition of varying amounts of nickel or cobalt. The production uses durable carbides that are not subject to decomposition and dissolution at high temperatures. Carbide can be cast or sintered. Carbides are brittle. In this regard, their grains are bonded with suitable metals to form a solid material. The latter are iron, cobalt, and nickel.

Cast connections

Carbide tools produced by this method are highly resistant to abrasion by the workpiece material and chips. They do not lose their characteristics at heating temperatures from 750 to 1100 degrees.

It has been established that products made by melting or casting with the addition of a kilogram of tungsten can process five times more material than objects made of high-speed steel with the same W content. One of the disadvantages of such compounds is their fragility. As the proportion of cobalt in the composition decreases, it increases.

The speed of carbide cutters is 3-4 times higher than that of steel.

Sintered materials

They involve a metal-like compound bonded by an alloy or metal. As a rule, carbide (including complex ones) of titanium or tungsten, as well as tantalum, titanium carbonide, is used as a base. Borides are used less frequently in production.

The matrix for holding the grains of the material is a binder - an alloy or metal. As a rule, it is cobalt. It is a carbon neutral element. Cobalt does not form its own carbides and does not destroy others.

Less commonly used in combination is nickel and its compound with molybdenum.

Comparative characteristics

Sintered materials are produced by the powder method. Processing of hard alloys of this type is carried out only by grinding or by physical and chemical methods (laser, acid etching, ultrasound, etc.). Cast products are subjected to hardening, annealing, aging, and so on. They are designed for surfacing on tools. Powdered materials are attached by soldering or mechanically.

Features

The main properties of hard alloys are their high strength and wear resistance. At the same time, the materials under consideration are characterized by lower viscosity and thermal conductivity in comparison with steel. This must be taken into account when using the products. When choosing a hard alloy, you must adhere to a number of recommendations:

1. Tungsten products, in comparison with titanium-tungsten products, have a lower weldability temperature with steel. In this regard, they are used to work with cast iron, non-ferrous metals and non-metallic materials.
2. For steel, it is advisable to use compounds of the TK group.
3. TTK grade hard alloy has increased viscosity and accuracy. It is used to work with steel forgings and castings in unfavorable conditions.
4. Finish and fine turning with a small chip cross-section is provided by carbide burrs with a fine-grained structure and lower cobalt content.
5. Under unfavorable conditions and rough work with shock-loaded materials, it is advisable to use compounds with a high cobalt content. Moreover, they must have a coarse-grained structure.
6. Finishing and roughing in the continuous cutting process are carried out predominantly with compounds with a medium percentage of cobalt.

Powdered materials

They are presented in two groups: containing and not containing tungsten. In the first case, the hard alloy is presented in the form of a mixture of technical powdered W and ferrotungsten with carburizing components. It was manufactured in the USSR. This hard alloy is called “wokar”. The material manufacturing process is as follows:

1. High-percentage ferrotungsten and technical powdered W are mixed with ground coke, soot and other similar components.
2. The resulting mass is mixed with sugar molasses or resin into a thick paste.
3. Briquettes are pressed from the mixture and lightly fired. This is necessary to remove volatile compounds.
4. After firing, the briquettes are ground and sifted.

The finished material thus has the appearance of fragile black grains. Their size is 1-3 mm. A distinctive feature of such materials is their high bulk weight.

Stalinite

This carbide alloy does not contain tungsten, which makes it low in cost. It was also invented in the Soviet years and is widely used in industry. As practice has shown, despite the fact that this hard alloy does not contain tungsten, it has high mechanical characteristics, which in most cases satisfy technical requirements. Stalinite has significant advantages over tungsten materials.

First of all, it is a low (1300-1350 degrees) melting point. Tungsten materials undergo changes only starting at 2700 degrees. A melting temperature of 1300-1350 degrees greatly facilitates surfacing and increases its productivity. The basis of stalinite is a mixture of cheap powdered ferroalloys, ferromanganese and ferrochrome. The production of this material is similar to the process for producing tungsten compounds.

Stalinite contains 16-20% chromium and 13-17% manganese.

Application

In modern industry, hard alloys are widely used. At the same time, materials are constantly being improved. The development of this manufacturing sector is carried out in two directions. First of all, the compositions of alloys are improved and their manufacturing technology is improved. In addition, innovative methods of applying compounds to products are being introduced. Carbide tools contribute to a significant increase in labor productivity.

This is ensured by the high wear resistance and heat resistance of the products. Such characteristics allow working at speeds 3-5 times higher than for steel. Modern burrs, for example, have such advantages.

Carbide materials manufactured using advanced technologies (electrochemical and electrophysical methods), including the use of diamond blanks, are among the most in demand in industry today.

Developments

Today, various studies are being carried out in the domestic industry, including an in-depth analysis of the possibility of increasing the characteristics of hard alloys. They mainly concern the granulometric and chemical composition of materials.

As a fairly successful example over the past few years, we can cite the compounds of the TSN group. Such alloys are specially designed for friction units operating in an aggressive acidic environment. This group continues to develop new compounds in the VN group proposed by the All-Russian Scientific Research Institute of Traumatology and Technology.

During the research, it was found that by reducing the grain size of the carbide phase, characteristics such as strength and hardness of the alloys significantly increase. The use of technologies for regulation and plasma restoration of particle size distribution today makes it possible to produce materials whose fraction size is less than a micron. TSN grade alloys are today widely used in the production of oil and gas and chemical pump components.

Russian industry

One of the leading enterprises engaged in the field of production and scientific development is the Kirovograd Hard Alloy Plant. KZTS has extensive in-house experience in introducing innovative technologies into production. This allows it to occupy a leading position in the Russian industrial market.

The company specializes in the production of sintered carbide tools and products, metal powders. Production began in January 1942. At the end of the 90s, the enterprise was modernized.

Over the past few years, the Kirovograd Hard Alloy Plant has been focusing its activities on the production of improved multifaceted replaceable inserts with wear-resistant multilayer coatings. The company is also developing new tungsten-free compounds.

Conclusion

The positive experience of many industrial enterprises suggests that in the near future tungsten-free alloys will not only become even more popular, but will also be able to replace other materials used for the production of stamping and cutting products, elements of machines operating in harsh conditions, fixtures and equipment. Today, a whole group of compounds based on titanium carbonitride and carbide has already been created.

They are used in many industrial areas. In particular, hard alloys TV4, LTSK20, KTN16, TN50, TN20 are widely used. New developments include materials of the tantalum TaC, niobium NbC, hafnium HfC, and titanium TiC groups. The production of tools using these alloys makes it possible to replace tungsten with relatively cheap additives, thus expanding the range of raw materials used.

This, in turn, ensures the production of products with specific properties and higher performance characteristics.

Source: https://www.syl.ru/article/205207/new_tverdyiy-splav-marki-harakteristiki-primenenie-tverdosplavnyiy-instrument

Characteristics and properties of hard alloys

With the development of technology and increasing demands regarding the reliability and durability of metals, manufacturers have tried to create a hard alloy that would satisfy the needs of customers. Ultimately, they were able to create a refractory metal that met the requirements of the developing industry. Metallurgists did not stop at one successful connection and continued to develop production.

Tungsten alloy

Basic information

Hard alloys are common in various industries. They are used to make parts for machine tools, cars, ships, aircraft, fasteners, building plates and other products. They are often used in the production of tools. It is advisable for people involved in metallurgy and blacksmithing to know basic information about what carbide is.

History of discovery

The history of the discovery of hard alloys begins at the beginning of the 20th century. Before this period, metalworking tools were made from tool steel, which was infused with carbon. However, the processing process was low-productivity and uneconomical.

By the beginning of the 20th century, high-alloy tool steel was developed through the joint efforts of metallurgists. It began to be used when processing difficult-to-cut types of metals at high speeds. After a short period of time, it received the name “high-speed steel.” Instruments made from it were first demonstrated to the public in 1910.

The development of tool technology did not stop there. In the USSR, USA and Germany, starting from 1925, mixtures of hard metals began to be produced as commercial products. Such products were made from tungsten carbide and cobalt metal.

In the CIS countries, this alloy was called “win.” However, the new material could effectively process cast iron workpieces, but not steel. In this regard, the development of new compounds continued and in 1935 a tungsten-titanium mixture appeared.

It was suitable for processing steel, but crumbled when working with cast iron.

In subsequent years, synthetic diamonds began to be used to coat the working parts of tools. Another development was elbor - a compound of nitrogen and boron.

How to obtain hard alloys

Metal compounds are a mixture of powders that are pressed and baked. It contains carbides and cobalt. The powders are mixed in baking dishes and pressed under a pressure of 200 kgf/cm2. After pressure treatment, the molds are heated to a temperature of 1500 degrees. Ready-made compounds are used in the production of difficult-to-process materials.

Properties of hard alloys

To understand which metal or mixture is the strongest in the world, you need to know their properties. The main characteristics will help you understand certain types of materials and use them wisely in production. Properties of hard alloys:

1. High mechanical and thermal shock strength.
2. Wear resistance.
3. Red fastness. This indicator appears at temperatures from 900 to 1000 degrees.

Properties of hard alloys such as impact resistance, ductility, compressive or bending strength and hardness directly depend on the amount of cobalt contained in the compounds. The grain size of the tungsten carbide is also important.

Characteristics of hard alloys

To determine the hardest alloy, you need to understand the characteristics. These include the chemical composition of the metal compound, its mechanical and physical properties, and the process of obtaining finished alloys.

Mechanical and physical characteristics:

1. Heat resistance.
2. Density (14.9g/cm3–15.2g/cm3).
3. Hardness (89.5HRA-91 HRA).
4. Thermal conductivity - 51 W.
5. Permissible strength - 2150 MPa.

These characteristics also include the resistance of the compounds to the effects of corrosive processes. The hardest alloy has inflated physical and mechanical characteristics.

Stamps

According to state GOSTs, special markings are established that mark all compounds of hard metals. It consists of capital letters and numbers:

1. VK6M - tungsten-cobalt mixture. The number 6 indicates the amount of cobalt in the composition. The letter “B” indicates tungsten, respectively, the letter “K” indicates cobalt. The letter “M” indicates the area in which this alloy is used. Tools for metal processing are made from it.
2. VK2 - in this case the mixture contains 2% cobalt and 98% tungsten.
3. BK8 - this mixture of cobalt contains up to 8%.
4. T14K8 - such compounds contain a third element - titanium. It contains 14% of it. Cobalt 8%. Everything else is tungsten.
5. T5K10 - similar to the previous mixture, in which 5% titanium, 10% cobalt and 85% tungsten.
6. TT7K12 - tantalum is added to the above elements. Its percentage is the same as that of titanium.

Alloy grades are indicated on finished parts and blanks.

Areas of use

There are many applications for hard alloys. These include:

1. Production of tools for metal processing.
2. Manufacturing of parts for industrial equipment.
3. Equipment for working with metal workpieces.

Often hard alloys are used as a coating on softer ones. The scope of application extends to the construction of large transport vehicles.

Classification

There is a special international classification called “ISO”. It divides domestic and foreign hard alloys by area of ​​application. Marked with letters from the Latin alphabet:

1. K - used for cast iron.
2. N - processing of non-ferrous metals and alloys similar to them.
3. H - used when working with hardened steel.
4. M - for stainless steel.
5. P - for castings with drain chips.
6. S - for working with heat-resistant alloys.

In addition to this classification, there is a division according to the chemical elements contained in the composition and the amount of basic metals.

Tungsten-containing

These compounds are used in the manufacture of cutting tools. They can be labeled as VK or VKM. The numbers will indicate the percentage of certain elements.

Titanium-tungsten-containing

These compounds are used to make equipment for processing steel at high speeds. The brand of these alloys is TK. The numbers indicate the cobalt and titanium content.

Titanium-tungsten alloy

How to choose the right grade of carbide

When choosing an alloy grade, you need to pay attention to their separation. These can be titanium-tungsten and tungsten mixtures. Steel is processed first, cast iron second.

Physical and mechanical characteristics also need to be taken into account. The power of the equipment with which the processing will be carried out plays an important role.

Advantages and disadvantages

Solid metal compounds have both advantages and disadvantages. Strengths include:

1. High mechanical and thermal shock strength.
2. Uniformity of structure.
3. The sharpening on the instrument lasts much longer.
4. High temperature resistance.

Disadvantages include the high price of tools and equipment made from solid compounds.

Hard alloy products

In hardware stores and markets you can find various products made from mixtures of hard metals. These can be various tools, parts for machines, machine tools, power tools, construction plates and other products.

4-4 Hard alloys and materials
Hard metal compounds are popular in construction, metallurgy, mechanical engineering and other industries. With their help, you can process hard materials, which was extremely problematic before their appearance.

However, you will have to pay a lot for this type of equipment.

Source: https://metalloy.ru/splavy/tverdye

Alloy VK8

Today, various industries are faced with the need to use products made from tungsten group materials.

Application of VK8

VK8 hard alloy is used for rough work:

• grinding down inhomogeneities on cut sections;

• countersinking of gray cast iron.

With its help, the surfaces of all types of steels are processed: alloyed, cast iron, heat-resistant; hard wood.

Rough turning with uneven cut section and intermittent cutting, planing, rough milling, drilling, rough drilling, rough countersinking of gray cast iron, non-ferrous metals and their alloys and non-metallic materials. Processing of corrosion-resistant, high-strength and heat-resistant difficult-to-machine steels and alloys, including titanium alloys.

Alloy VK8 GOST 3882-74 was installed back in the USSR - (view / download GOST). With the same percentage of tungsten, it has physical properties that differ significantly from similar ones that do not fall within the framework of a specific GOST.

GOST 3882-74 with information about VK8 alloy and other grades of hard alloy - click on the picture to view GOST

Where does the difference come from and what causes it?

The tabular characteristics of the VK8 alloy are achieved in production most often by powder metallurgy methods. Individual elements of future equipment are pressed into molds and sintered at the melting temperatures of cobalt. As a result, fairly reliable plates for cutters and drills are obtained.

The decoding of the VK8 alloy is simple: the content of tungsten carbide is 92, cobalt is 8% and is always maintained as such for a specific marking. Sometimes this composition is mistakenly attributed to Pobedit (90/10), but the difference of 2% is fundamental for tungsten compounds.

Moreover, metallurgists noticed that the hardness of the VK8 alloy, which came off the assembly line according to the Rockwell table, ranges from 91% sometimes to 86% (with absolutely identical proportions of tungsten and cobalt). It would seem that only 5%, but they greatly influenced the bending strength, MPa. In the first case, it was almost twice (2800) higher than the values ​​of GOST 3882 (1670).

Warehouse with cutters and VK8 plates

Additional studies have shown that the differences extend to material densities of 14.8 and 14.6 g/cm3, impact strength of 35-30 kJ/m², as well as an evaluation characteristic related to the anti-corrosion properties of metal in seawater.

After conducting a series of checks and experimental production of materials, metallurgists came to the conclusion that the following factors influence the production of the VK8 alloy, the composition of which remains unchanged:

• condition of the powders used (grain size, humidity);

• conditions for combining (mixing) tungsten carbide and cobalt;

• set temperature, pressure (accurate to units of measurement).

Given the difference, scrap collection points often indicate the characteristics of the material they buy. In addition to radiological purity, it must meet the requirements of specific technological conditions, which also have their own standards, the buyer informs about them in advance.

Interesting fact. Different grades of steel and alloys are color coded. VK8 GOST 3882 is marked in red, and its varieties are complemented by a blue stripe.

Metal blockages

Sometimes they take any hard alloy within the VK8 alloy grade. It is quite highly valued, but there is no single price on the market. An expert can tell you the exact price after examining the product.

In addition to the listed differences, there is added a factor associated with the type of metal connection of elements from VK8 with the base of the product.

Cutters with inserts made of VK8 alloy

The mounting methods are fundamentally different. The output is either pure tungsten/cobalt after mechanical fastening with screws or with soldering of brass and other connecting metals. Preference is always given to pure metals, however, given the metallurgical industry's shortage of tungsten and cobalt, the desire to reduce the production of ores containing these chemical elements is accepted by almost all types of alloys, but at different prices.

Foreign analogs of VK8 alloy

Germany	Sweden	Bulgaria	Hungary	Poland	Czech
DIN,WNr	SS	BDS	MSZ	PN	CSN
HG30, HG40	MC241	BK8	DR30, DR40	H30	G1.1, G2

Area of ​​use of tungsten-containing products

The use of VK8 alloy , like other similar types of vehicles, extends to various industries where it is necessary to drill wells in abrasive rocks, cut marble, harvest coal, and process granite. Tungsten products are also used in mechanical engineering for the manufacture of friction pairs for bearings, dies, and molds.

Special carbide elements (teeth) are installed on the cutters of the bits and on the paws - one of the most commonly used alloys is VK8

Already today, this type of metal has found an area of ​​application - especially durable coatings created by spraying technology. The most famous alloy VP3325 is made on its basis; it improves the properties of brittle joints with the following qualities:

• thermal conductivity, hardness;

• resistance to vibration.

VP3325 alloy plates

Meanwhile, this type of processing of low-strength materials is becoming increasingly popular and is used in medicine, optics, and the jewelry industry. This approach to instrumentation simultaneously reduces the cost of production, as well as the need for tungsten. Thanks to the possibility of using recyclable materials, some even foreign enterprises are provided with resources without additional extraction from the bowels of the earth.

Price for scrap metal of VK8 alloy

Average market prices for VK8 alloy throughout Russia. VK8 refers to hard alloy scrap, so the price is no different and is:

• VK8 pure alloy, without brazing - 850 rubles/kg;

• VK8 (napai) - 800 rub/kg.

Source: http://xlom.ru/vidy-metalloloma/splav-vk8/

Hard alloys

Hard alloys are hard and wear-resistant metal materials that can maintain these properties at 900–1150 °C. They are mainly made from highly hard and refractory materials based on tungsten, titanium, tantalum, chromium carbides, bound with a cobalt metal binder, with varying cobalt or nickel content.

Types of hard alloys[ | ]

There are sintered and cast hard alloys.

The main feature of sintered hard alloys is that products from them are produced by powder metallurgy methods and they can only be processed by grinding or physical and chemical processing methods (laser, ultrasound, etching in acids, etc.) and are also perfectly processed by the electro-physical method of electroerosion, and cast hard alloys are intended for surfacing on the tool being equipped and undergo not only mechanical, but often also heat treatment (hardening, annealing, aging, etc.).
Powdered hard alloys are fixed to the tool being equipped using soldering methods or mechanical fastening. Hard alloys are distinguished by the metal carbides present in them: tungsten - VK2, VK3, VK3M, VK4V, VK6M, VK6, VK6V, VK8, VK8V, VK10, VK15, VK20, VK25; titanium-tungsten - T30K4, T15K6, T14K8, T5K10, T5K12V; titanium-tantalum-tungsten - TT7K12, TT10K8B. Tungsten-free TNM20, TNM25, TNM30

Based on their chemical composition, hard alloys are classified:

• tungsten-cobalt hard alloys (VK);
• titanium-tungsten-cobalt hard alloys (TC);
• titanium-tantalum-tungsten-cobalt hard alloys (TTK).

Based on their intended purpose, hard alloys are divided (ISO classification) into:

• P - for steel castings and materials during the processing of which drain chips are formed;
• M - for processing difficult-to-cut materials (usually stainless steel);
• K - for processing cast iron;
• N - for processing aluminum, as well as other non-ferrous metals and their alloys;
• S - for processing heat-resistant alloys and titanium-based alloys;
• H - for hardened steel.

Due to the shortage of tungsten, a group of tungsten-free carbide alloys called cermets has been developed. These alloys contain titanium carbides (TiC), titanium carbonitrides (TiCN), bonded with a nickel-molybdenum base. Their manufacturing technology is similar to tungsten-containing hard alloys.

These alloys, compared to tungsten hard alloys, have lower bending strength, impact toughness, and are sensitive to temperature changes due to low thermal conductivity, but have the advantages of increased heat resistance (1000 °C) and low adhesion to the materials being processed, due to which they are not prone to build-up during cutting. Therefore, they are recommended to be used for finishing and semi-finish turning and milling. By purpose they belong to group P of the ISO classification.

Properties of hard alloys[ | ]

Carbide inserts HRA 86-92 have high wear resistance and red hardness (800-1000 °C), which allows processing at cutting speeds of up to 800 m/min.

Sintered carbide alloys[ | ]

Hard alloys are made by sintering a mixture of carbide and cobalt powders.

The powders are pre-made by chemical reduction (1-10 microns), mixed in the appropriate ratio and pressed under a pressure of 200-300 kgf/cm², and then sintered in molds corresponding to the size of the finished plates, at a temperature of 1400-1500 °C, in a protective atmosphere . Hard alloys are not subjected to heat treatment, since immediately after production they have the required set of basic properties.

Composite materials consisting of a metal-like compound cemented with a metal or alloy. They are most often based on tungsten or titanium carbides, complex tungsten and titanium carbides (often also tantalum), titanium carbonitride, and less often other carbides, borides, etc.

The so-called “binder” - metal or alloy - is used as a matrix to hold grains of solid material in the product.

Usually cobalt is used as a “binder”, since cobalt is a neutral element in relation to carbon, it does not form carbides and does not destroy the carbides of other elements, less often - nickel, its alloy with molybdenum (nickel-molybdenum binder).

Production of hard alloys by powder metallurgy[ | ]

1. Preparation of carbide and cobalt powders by reduction from oxides.
2. Grinding of carbide and cobalt powders (produced in ball mills for 2-3 days) to 1-2 microns.
3. Sift and re-grind if necessary.
4. Preparation of the mixture (powders are mixed in quantities corresponding to the chemical composition of the alloy being manufactured).
5. Cold pressing (organic glue is added to the mixture to temporarily maintain shape, such as PVA, paraffins or glycerin [1]).
6. Sintering under load (hot pressing) at 1400 °C (at 800-850 °C the glue burns without a residue). At 1400 °C, cobalt melts and wets the carbide powders; upon subsequent cooling, the cobalt crystallizes, connecting the carbide particles together.

Nomenclature of sintered hard alloys[ | ]

Hard alloys can be divided into three main groups:

• tungsten-containing hard alloys
• titanium-tungsten-containing hard alloys
• titanium tantalum tungsten carbide alloys

Each of the above groups of hard alloys is divided in turn into grades that differ in chemical composition, physical, mechanical and operational properties.

Some grades of the alloy, having the same chemical composition, differ in the grain size of the carbide components, which determines the difference in their physical, mechanical and operational properties, and hence the areas of application.

The properties of hard alloy grades are designed in such a way that the produced range can satisfy the needs of modern production to the maximum extent. When choosing an alloy grade, you should take into account: the scope of the alloy, the nature of the requirements for the accuracy of the processed surfaces, the condition of the equipment and its kinematic and dynamic data.

The designations of alloy grades are based on the following principle:

Group 1 - alloys containing tungsten carbide and cobalt. They are designated by the letters VK, followed by numbers indicating the percentage of cobalt in the alloy. This group includes the following brands:

VKZ, VKZM, VK6, VK6M, VK6OM, VK6KS, VK6V, VK8, VK8VK, VK8V, VK10KS, VK15, VK20, VK20KS, VK10KHOM, VK4V.

Group 2 - titanium-tungsten alloys containing titanium carbide, tungsten carbide and cobalt. It is designated by the letters TK, while the number after the letters T indicates the % content of titanium carbides, and after the letter K - the cobalt content. This group includes the following brands: T5K10, T14K8, T15K6, TZ0K4.

Group 3 - titanium-tantalum-tungsten alloys containing titanium, tantalum and tungsten carbide, as well as cobalt and are designated by the letters TTK, with the number after TT % content of titanium and tantalum carbides, and after the letter K - cobalt content. This group includes the following brands: TT7K12, TT20K9.

Group 4 - alloys with wear-resistant coatings. They have the letter designation VP. This group includes the following brands: VP3115 (VK6 base), VP3325 (VK8 base), VP1255 (TT7K12 base).

Hard alloys used for metal cutting: VK6, VKZM, VK6M, VK60M, VK8, VK10KHOM, TZOK4, T15K6, T14K8, T5K10, TT7K12, TT20K9.

Hard alloys used for chip-free processing of metals and wood, wear parts of machines, instruments and devices: VKZ, VKZM, VK6, VK6M, VK8, VK15, VK20, VK10KS. VK20KS.

Hard alloys used to equip mining tools: VK6V, VK4V, VK8VK, VK8, VK10KS, VK8V, VK11VK, VK15.

In Russia and the former USSR, the following sintered hard alloys are used for metal cutting [2]:

Foreign manufacturers of hard alloys, as a rule, each use their own brands of alloys and designations.

Developments[ | ]

Currently [ when? ] in the Russian hard alloy industry, in-depth research is being carried out related to the possibility of increasing the performance properties of hard alloys and expanding the scope of application. First of all, these studies concern the chemical and granulometric composition of RTP (ready-to-press) mixtures.

One of the successful examples in recent times is the alloys of the TSN group (TU 1966-001-00196121-2006), developed specifically for working friction units in aggressive acidic environments. This group is a logical continuation in the chain of VN alloys on a nickel binder, developed by the All-Russian Research Institute of Hard Alloys.

It was experimentally observed that with a decrease in the grain size of the carbide phase in a hard alloy, the hardness and strength increase qualitatively. Technologies for plasma reduction and regulation of particle size distribution currently make it possible to produce hard alloys with grain sizes (WC) in which the grain size can be less than 1 micrometer.

TSN-group alloys are widely used in the production of Russian-made chemical and oil and gas pump components.

Cast hard alloys[ | ]

Cast hard alloys are produced by melting and casting.

Application[ | ]

Carbide alloys are currently a common tool material widely used in the tool industry. Due to the presence of refractory carbides in the structure, carbide tools have high hardness HRA 80-92 (HRC 73-76), heat resistance (800-1000 °C), so they can work at speeds several times higher than the cutting speeds for high-speed steels.

However, unlike high-speed steels, hard alloys have reduced strength (σi = 1000-1500 MPa) and do not have impact toughness.

Hard alloys are low-tech: due to their high hardness, it is impossible to make a solid shaped tool from them, in addition, they can be ground to a limited extent - only with a diamond tool, therefore hard alloys are used in the form of plates, which are either mechanically fixed to the tool holders or soldered to them.

Due to their high hardness, hard alloys are used in the following areas:

• Cutting of structural materials: cutters, milling cutters, drills, broaches and other tools.
• Equipment of measuring instruments: equipment of precision surfaces of micrometric equipment and supports of scales.
• Branding: equipping the working part of the stamps.
• Drawing: equipping the working part of the drawing.
• Stamping: equipping dies and dies (cutting, extrusion, etc.).
• Rolling: carbide rolls (made in the form of rings made of carbide, placed on a metal base)
• Mining equipment: brazing of sintered and surfacing of cast hard alloys.
• Production of wear-resistant bearings: balls, rollers, cages and spraying on steel.
• Ore processing equipment: equipping work surfaces.
• Gas thermal spraying of wear-resistant coatings

See also[ | ]

• Chromium-cobalt-molybdenum alloys

Links[ | ]

• Hard metal-ceramic alloys and cermets

Basic principles of designation of alloy gradesHard alloys - Classification, areas of application

Literature[ | ]

• Construction materials. Edited by B. N. Arzamasov. Moscow, publishing house "Mechanical Engineering", 1990.
• Technology of construction materials. Ed. A. M. Dalsky. Moscow, publishing house "Mechanical Engineering", 1985.
• Stepanchuk A.N., Bilyk I.I., Boyko P.A. Technology of powder metallurgy.-K.: Vishcha school., 1989.-415p.
• Skorokhod V.V. Powder materials based on refractory metals and compounds.-K.: Tekhnika, 1982.-167p.

Source: https://encyclopaedia.bid/%D0%B2%D0%B8%D0%BA%D0%B8%D0%BF%D0%B5%D0%B4%D0%B8%D1%8F/%D0% A2%D0%B2%D1%91%D1%80%D0%B4%D1%8B%D0%B9_%D1%81%D0%BF%D0%BB%D0%B0%D0%B2

What is carbide

Hard alloys of standard grades are made on the basis of tungsten, titanium and tantalum carbides. Cobalt is used as a binder.

Depending on the composition of the carbide phase and binder, the designation of hard alloys includes letters characterizing the carbide-forming elements:

• B - tungsten
• T - titanium
• TT - (second “T”) tantalum
• K - cobalt

Mass fractions of elements are expressed as a percentage, their sum is 100%. For example, grade VK8 (single-carbide alloy) contains 8% cobalt and 92% tungsten carbides; grade T5K10 (two-carbide alloy) contains 5% titanium carbides, 10% cobalt and 85% tungsten carbides; grade TT8K6 (three-carbide alloy) contains 6% cobalt, 8% titanium and tantalum carbides, 86% tungsten carbides.

Properties and applications of hard alloys

The issue of increasing the cutting speed of steel remains relevant for a long period of time. Engineers and professors are solving it; they are creating materials with high hardness, heat resistance and wear resistance. For the first time, an analogue of the VK8 hard alloy appeared at a German plant in the 1930s. The cutting speed when using this material has become maximum compared to other tool metals.

Interpretation of VK8 steel

The name of the alloy stands for:

• B – use of tungsten in the composition;
• K8 – 8% cobalt.

92% of the material is tungsten carbide, the rest is cobalt. Depending on the grain size, the name of the VK8 alloy may contain other indices - M (fine), B (coarse). In the absence of an additional letter, the grain has a medium size.

VK8 alloy. GOST 3882-74

Chemical composition and preparation

The composition of the metal includes:

Cobalt is used to bind tungsten carbide. This is a metal similar in appearance to ferrum, but its shade is darker. Its use in the composition makes the alloy more malleable and durable. Tungsten carbide is a chemical compound of tungsten and carbon.

The composition of the VK8 alloy includes small fractions of a carbide compound and cobalt, which allows us to consider the material a product of powder metallurgy. To obtain them you need to perform several actions:

• grind the mixture;
• divide it into factions;
• mix the fractions in the required proportions;
• form the workpiece using a press and adhesive;
• process at a load of 30 MPa and a temperature of 1400 degrees.

Source: https://crast.ru/instrumenty/chto-takoe-tverdyj-splav

Inflatable single-seater PVC boat. Advantages and disadvantages

: 01/19/2020 Category: Author's essay

PVC! A single-seater boat is the best solution for those who are planning to go fishing or simply move to an uninhabited island to relax. All the benefits are in weight and dimensions. Yes, even a light girl will fit into your “one-room apartment”. However, each type of amateur watercraft has both weak and strong sides.

That is, here we will look at the pros and cons of a single-seater inflatable boat. In every detail, based on the opinions of thousands of users of this undoubtedly convenient PVC product.

And also to the responses of experts working with the designated products - employees of the Boats of Russia store. So, after studying this article, you may understand: what kind of “diamond” do you need from the bright collection called PVC inflatable boats.

Single rowing boat PVC. Peculiarities

First of all, it is worth pointing out that the desired single-seater inflatable boat is made of polyvinyl chloride. A fabric that is often incorrectly called "rubber". In fact, it is stronger than rubber in terms of durability. To mechanical and chemical influences.

Boats made from it today perform 4 functions. Thanks to this fact, the once universal product over time was divided into 4 categories of popular goods:

• beach (often single-layer with very light paddles or no paddles at all);
• walking (multilayer, with a seat, sometimes with a keel);
• fishing (multi-layer, with a seat, with rings for accessories);
• hunting (multilayer, with a seat, with the same rings, also with a hard bottom).

The lightest single-seater PVC boat is a device for water resort procedures. It is used exclusively for mini-coastal swimming (2-5 meters from the shore: usually the beach one). Only one body is placed there. There are no places for benches, fishing rods, motors and anything else.

Accordingly, the demand for such a product is small. And this affects the minimum thickness of the material and size. In the end it comes down to price. It is minimal in this position. Visually, such “transport” is also identified by its “cheerful” colors.

And simplicity (the pump is manual; some kits don’t even have oars or other accessories).

Now about the last 3 options, originally intended for water travel or even for fishing - both fishing and hunting. Let's make a reservation that in this review we are only interested in a single-seater PVC boat. With an inflatable bottom and a regular one. With and without transom. Just rowing and “self-propelled” (the latter will be discussed in Chapter 2)

Walking models “begin” with products that are already reinforced with additional layers of the fabric mentioned above. They are “welded” onto the cord on both sides. They also feature longer oars, a waterproof duffel bag and an inset bench.

A fishing polyvinyl chloride “shuttle” is slightly different from a pleasure boat. Mainly accessories. It is also reinforced (calculation for a minimum of 120 kg of weight!). However, sometimes it’s not 5, but 9 layers. This time it is equipped with a foot pump. It is immediately noticeable by the presence of serious oars and a comfortable seat of the Liktroz-Likpas system.

However, in the fishing type of boat, its additional know-how is already evident - mounting for a motor. The fact is that a single-seat PVC boat with a transom allows you to mount an “engine” without damaging the surface. But more on that later. Here we will tell you how the hunting variety differs from those described above.

Mainly, the bottom that comes with the kit. It is hard - made of a material containing wood. Either solid, or slate (assembled from flat planks that fit “expanded”). That is, the “captain” can stand firmly at his full height. To shoot a bird. At the same time, the boat is designed in such a way as to oscillate less on the water. 3rd point – camouflage colors for vehicles. Products for fishermen have more fastening rings for all sorts of very special accessories.  

If we are already talking about the bottom, then it can also be inflatable (NDND). That is, it consists of several chambers filled with air. This gives the product stability when the passenger moves. Moreover, without using a plywood floor (which is inconvenient to transport). Boats of all named categories can be equipped with NDND. However, they are correspondingly a little more expensive.

Motor single boat PVC. Peculiarities

As we have already noticed, it is possible to install a motor on a single-seater PVC rowing boat. Therefore, the last three varieties are also divided according to the “motor/non-motor” principle. The “motor boat” differs from the rest of its sisters by the presence of a transom - an object made of bakelite plywood, which is glued or hung into the aft part of the boat space.

This is the same feature of a lightweight single-seater PVC boat, which in terms of performance puts it on par with similar products made of wood, fiberglass or aluminum. It was with the invention of the transom that “PVC transport” became so popular with most fishermen, inspectors of the Ministry of Natural Resources or state reserves.

But also the forces of the Ministry of Emergency Situations or the Ministry of Internal Affairs of Russia.

Most often, a single-seater PVC boat with a motor catches the eye with a certain configuration. The density of the layers and the strength of the welding itself are such that in terms of strength it is a bit like fiberglass. Often, a fairly heavy motor will no longer crush or sink such a hard “vessel” in water. That's not all.

The sides (now shaped not like an oval, but like a horseshoe) are much higher and more massive than in conventional PVC. And they often resemble RIBs - boats with fiberglass parts. Tulin models, “born” in Kirov, are the best example of the qualities that are presented here. Engines (Sea Pro, Gulfstream and Hangkai) are mounted at the rear.

There is no side there - just a solid transom adjacent to the front of the very hard floor of the mini-vessel. The boat differs from the RIB only in the absence of fiberglass (aluminum) parts.

The “self-propelled” inflatable single-seater boat is so inconspicuous, maneuverable and fast that it is often used by security forces. It was even originally invented for naval reconnaissance and the Marine Corps. Another “business card” of such a product is its special stability.

Advantages and disadvantages of single-seater PVC boats

What benefits does a single-seater inflatable boat bring to your travels?

• compactness – a deflated “odnushka” is suitable not only for the trunk, but even for a bag (accordingly, you can store it anywhere, and not in a special garage);
• lightness - despite all the density and multi-layering, the material of a single-seater boat is practically weightless (however, it is better to carry the “motorized” varieties in the trunk);
• a single-seater PVC rowing boat is more silent (but the waves hit fiberglass and, even more so, aluminum in such a way that they scare away both fish and flying game);
• speed of preparation for rafting - small, and even inflatable (putting such a boat on the water is much faster than removing an aluminum boat from a car trailer or inflating a 3-5-seater PVC (filling all its chambers with air takes much longer);
• combining the listed qualities, a single-seater PVC boat with a motor is sometimes not inferior to rigid vessels in terms of functionality related to speed;
• ease of rowing - a smaller and lighter boat requires less effort;
• inexpensive repairs - just glue the PVC products in the problem area (weld on a patch).

When talking about single-seater PVC boats, it would be unfair to take into account only the advantages of such products. In this part of the section we will talk about the “fly in the ointment”.

• small size - during a family walk, the main difference between the product you are looking for immediately turns into a disadvantage (most one-room cars have a carrying capacity of no more than 120 kg: if the owner is of average weight, only a child or a light woman will join him, if he is large - no one);
• the effect of a raised nose - the bow of a conventional PVC motor makes it take off (“the captain” of such a “ship” experiences significant inconvenience when turning);
• instability when moving a person - a regular (tensioned) bottom is a real test for someone who is getting acquainted with such a boat for the first time (if you are planning on a boat trip and not fishing, take the bottom as well);
• relative physical vulnerability - a single-seater PVC boat can run into the reinforcement of destroyed coastal fortification slabs, steel wire, or “strike” its bottom against sharper objects. What saves you from snags and from collisions with formidable but non-metallic objects is already useless here;
• time spent on assembling the floor and installing the motor - complex PVC (motor, with a separate hard floor, complete with benches and accessories) take much more time to prepare for rafting than a classic hard boat standing ready in the boathouse - comfortable and already equipped "stuffing")

Now, faced with the choice of material and dimensions of the boat, you are armed with a little knowledge that will help you decide. Pros and cons are relative. Each of them manifests itself in certain situations. Consequently, the reader must clearly decide what kind of water adventures await his future transport. Taking into account these specifics, it is worth making a final decision.

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Source: https://gotonature.ru/2158-naduvnaja-odnomestnaja-lodka-pvh-pljusy-i-minusy.html

Hard alloys, their characteristics, types, properties

4 October 2017 14:23

// Metalworking

Hard alloys include a separate group of extremely wear-resistant metal compounds that retain their physical and performance characteristics under intense mechanical and thermal stress. Hard steels are made from hard, refractory titanium, tungsten, chromium, and tantalum compounds. The connecting link is cobalt and iron-nickel components.

The main characteristics that determine the properties of steels and their purpose include:

• percentage value of the chemical elements included in the composition (determined in accordance with GOST);
• physical and mechanical properties (permissible bending strength, hardness, density, thermal conductivity parameters, corrosion resistance, heat resistance);
• manufacturing technology (cast or sintered compositions).

The carbides used in production are not subject to dissolution and destruction at excessive temperatures. But they are fragile, therefore, to form the required level of hardness of the product, they are bonded with other metals.

Properties of hard alloys

The most important properties of hard steels are strength, wear resistance, and hardness. In addition, refractoriness, heat-resistant and heat-resistant parameters play a practical role.

Properties vary depending on the group the alloy belongs to and its brand. Adding elements with the desired properties to the structure allows you to create a material with specified operating parameters.

Advantages:

• High strength, wear-resistant characteristics and hardness;
• Excellent parameters of heat resistance and heat resistance;
• Infusibility.

Flaws:

• High cost of tungsten-containing grades;
• Lower toughness and high susceptibility to impact, relative to high-speed steels.

Areas of application of hard alloys

Hard metal alloys are actively used in the production of equipment and tools for finishing difficult-to-process materials, parts of machine tools and machines subject to intense loads.

Main areas of use:

• production of tools for metal cutting: milling cutters, broaches, drills, cutters;
• equipment for mining and logging equipment: drills, working surfaces of equipment, devices for cutting;
• production of durable bearings: cages, balls, rollers, spraying on housings;
• tools and machine parts for drawing, stamping, calibrating, rolling, pressing, branding: equipment for the working surface, dies and dies, etc.;
• equipping measuring equipment: tool parts, working surfaces;
• surface spraying on parts made of other materials to give them better wear resistance, heat resistance, hardness, and anti-corrosion properties;
• production of elements for household and industrial devices: resistors, rheostats, electric heaters, parts for laboratory and industrial furnaces.

Hard alloy products

The main type of product offered by manufacturers and metalworking companies is cutting tools. Drills, cutters, plates, rods are the most popular products in the carbide metal segment.

Equipping production with tools and equipment made of high-hard alloys significantly increases the productivity and efficiency of technological processes and allows the use of modern metal processing technologies.

This has a positive effect on the quality and speed of metal products produced.

Source: https://indust.by/info/articles/metalloobrabotka/tverdye-splavy-ikh-svoystva-i-kharakteristiki/