SU1500700A1 - Composition for tunsten nitriding of steel articles - Google Patents

Description

The invention relates to metallurgy, in particular to compositions for

2

diffusion saturation of steel products with tungsten and nitrogen, and can be used in the manufacture of tools, machine parts, instruments and mechanisms. The aim of the invention is to increase the wear resistance and heat resistance of products. The composition contains, by weight.X: tungsten powder 40-50; ammonium chloride 3-5; cast iron chips 6-10; ammonium tungsten phosphate 16-20; alumina rest. This allows you to increase the wear resistance of 1.4-2.0 times, and heat resistance of 285-300 ° C. 2 tab.

The invention relates to metallurgy, in particular to chemical heat treatment, namely to the process of diffusion saturation of steel products with tungsten and nitrogen, and can be used in the manufacture of tools, machine parts, instruments and mechanisms.

The purpose of the invention is to increase the wear resistance and heat resistance of products.

The composition for tungsten nitrating of steel products, containing tungsten powder, ammonium chloride and alumina, additionally contains ammonium tungsten phosphate and cast iron chips at the following ratio

[Components, wt.X: Tungsten powder 40-50 Ammonium chloride 3-5 Cast iron chips 6-10 Tungsten phosphate ammonium 16-20

Alumina Rest

The temperature of the process of tungsten-nitriding is 900-1200 ° C, the duration of exposure to 2-12 hours

As a result of this treatment, a diffusion layer is formed on the surface of steel products, which has high hardness and heat resistance. ”

Tungsten powder is introduced in order to obtain atomic tungsten, which diffuses into the surface layers of the products.

Ammonium chloride is an activator.

Cast iron chips prevent the decarburization of products.

The decomposition of ammonium tungsten phosphate produces atomic nitrogen and tungsten, which, diffusing into the surface layers of the products, form a wear-resistant and heat-resistant diffusion layer. In addition, Vol8TS „„ 1500700 A1

3 1500700 4

ammonium framophosphate increases the saturated ability of the composition.

Aluminum oxide prevents products from welding the particles of the composition to the products, as well as their sintering.

The process of tungsten nitriding is as follows.

Products intended for tungsten-freezing are degreased in a hot (80-90 ° C) 5% alkaline solution and dried at 100-150 ^σ 0. The cooled products are placed in containers with fusible closures, the mixture of the above-mentioned ^ 5 composition is loaded, loaded in an electric furnace, heated to 900-1200 ° C and kept at this temperature for 2-12 hours

Together with the products, samples made from the same steel grade as the products, which determine the thickness of the diffusion layer, its hardness, wear resistance and heat _, are subjected to tungstenization _; resilience. 25

After the end of the tungsten-freezing, the containers are discharged from the furnace, cooled to room temperature and unsealed.

The effectiveness of the proposed SOS-30 tava for sub ^{volframoazotirovaniya:} confirmed by the examples.

Example 1. Samples made of 08 kp steel were subjected to tungsten-azotization in various compositions. The process temperature is 900 ° C, the dwell time is 6 hours. After processing, the samples are subjected to wear tests on a MI brand friction machine, dd determine the thickness of the diffusion layer, its hardness and heat resistance

The test results are presented in table.1.

As can be seen from table 1, the wear resistance of the samples after treatment in the proposed composition is 1.4-2.0 times higher ^ and the heat resistance is 285-300 ° C higher than after treatment in a known composition.

When the content of active components in the composition for tungsten nitrating is less than the lower limit values, the wear resistance and heat resistance of the samples increase slightly compared to samples processed in the known composition, and when the content of active components exceeds the upper limit values, the wear resistance and heat resistance of samples do not increase compared to , processed in an optimal composition.

The proposed composition for tungstenization has a saturation capacity of 20-30% higher than that known.

Example 2. Samples made of steel grades 10, 40Х, 4Х5В2ФС, У10 and Р6М5 are subjected to tungsten-freezing in a known composition (see table 1) and in the proposed (table 1) method described above. The process temperature is 200 ° C, the duration of the spin is 2 h. After processing, the samples are subjected to wear tests, determine the thickness of the diffusion layer, its hardness and heat resistance.

The test results are presented in table 2.

As can be seen from table 2, when using the proposed composition for tungsten-nitrating steel products, the wear resistance and heat resistance of the products increase, it has a high saturability.

Claims (1)

Claim The composition for the tungsten-nitrating of steel products, containing tungsten powder, ammonium chloride and aluminum oxide, characterized in that, in order to increase the wear resistance and heat resistance of the products, it additionally contains ammonium tungsten phosphate and cast iron chips in the following ratio of ί MNF "/ about · Tungsten powder 40-50 Ammonium chloride 3-5 Cast iron chips 6-10 Ammonium Tungsten phosphate 16-20 Alumina The rest: five 1500700 Table 1 Mixture Composition, wt.% Thickness layer, um Hardness, MPa • Wear, g / cm h Heat resistance, ° С one Tungsten powder 35 70 5000 0.53 400 Ammonium chloride 2 Cast iron chips Tungsten phosphate five . ammonium 15 Alumina 43 2 Tungsten powder 40 86 15800 0.40 635 Ammonium chloride 3 Cast iron chips Tungsten phosphate 6 ammonium sixteen Alumina 35 3 Tungsten powder 45 95 16,000 0.38 640 Ammonium chloride four Cast iron chips Tungsten phosphate eight ammonium 18 Alumina 25 four Tungsten powder. 50 98 16,500 0.31 650 Ammonium chloride five Cast iron chips Tungsten phosphate ten ammonium 20 Alumina 15 five Tungsten powder 55 98 16,500 0.31 650 Ammonium Chloride 6 Cast Iron Chips 12 Ammonium Tungsten Phosphate 22 Aluminum oxide 5 Known composition 6 Tungsten powder 60 65 1400 0.62 350 Ammonium chloride 3 Alumina 37 table 2 4 b ——————-- “" - ”T -----——-------- Thickness layer, um Layer hardness MPa Wear, Λ ⁹ g / cm "h Heat resistance ° s Composition Wednesday Steel Famous ten 100 3000 0.54 360 40x 90 3500 0.50 380 ' 4H5V2FS 85 4,000 0.48 550 Y10 44 4800 0.47 400 Famous Р.6М5 42 5000 0.42 620 Proposed ten 132 16600 0.28 640 40X 120 16800 0.25 640 4H5V2FS 118 17,000 0.24 645 Y10 96 18,000. 0.20 650 R6M5 ' 95 18,500 0.16 650