SU943321A1 - Composition for diffusion boronizing of metal products - Google Patents

Description

(54) COMPOSITION FOR DIFFUSION BORIATION OF METAL PRODUCTS

The invention relates to mechanical engineering, in particular to the chemical heat treatment of metals and alloys in powder saturating media, namely the diffusion saturation of metals and alloys with boron, and can be used in engineering, oil, chemical and other industries to increase operational durability of machine parts and tooling. Diffusion boronation in powdery media is known, using as the source of active boron atoms amorphous boron, its carbide salt and oxide, boron l. The disadvantages of the known composition for diffusion saturation are the scarcity and high cost of boron carbide or amorphous boron powders and the impossibility of getting deep and uniform in the thickness of the boride layers. The closest to the invention is the composition of L2 for the boronation of etals and alloys, containing oxide ora, aluminum (powder), alumina oxide and sodium fluoride with the following ratio of ingredients, wt.%: Boron oxide 15-20 Aluminum (powder) Sodium fluoride 0, Aluminum oxide Else To the disadvantages of a known composition, the strength of the low saturating ability is unsatisfactory wear and corrosion resistance. The purpose of the invention is to intensify the process of saturation and increase the wear and corrosion resistance of the treated surface. This goal is achieved by the fact that calcium carbide and cryolite are additionally introduced into the composition containing boric oxide and alumina in the following ratio of components, in wt.%: Boron oxide BS-tO Calcium carbide 10-15 Cryolite3 5 Aluminum oxide kQ- 52 Calcium carbide (CaGj) - compound. calcium with carbon. Pure calcium carbide is completely colorless and transparent, and the technical one consists of solid, opaque pieces of dark gray color. Calcium carbide is obtained by heating a mixture of quick lime (calcium oxide) with coal. Used for the production of acetylene, calcium cyanamide and alkali metal reduction. Cryolite () - yneral, natural fluoride. Artificial cryolite is produced by the interaction of aluminum hydroxide with hydrofluoric acid and subsequent neutralization of the acidic soda solution. To form a gas phase during saturation as cryolite is used in the process activator. 3 V, 4 Boron oxide is a supplier of active boron atoms, calcium carbide is a reducing agent, and aluminum oxide is an inert additive that prevents sintering of the mixture. Composition containing, masD: 35, CaCa.15, NajAlF 3, 7, diffusion saturation is carried out for an hour of steel and U8, as well as titanium alloy VT-1. Diffusion layers are obtained with a thickness of 300, 260 and 60 microns, respectively. Diffusion layers on steel consist of iron borides and "about-solid solution of boron in iron with microhardness for steel 15-1500 kg / mm, for V8 - 1–50 kg / mm. X-ray diffraction phase analysis of the titanium alloy shows that titanium boride TiB is formed on the surface, microhardness is 2800-2900 kg / mm. and about solid solution of boron in titanium. Data on the processing of materials in similar temperature-time conditions, but with different ratios of the components are shown in the table.

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Claims (2)

a: “3 s z 79 As can be seen from the table, under the proposed temporal conditions, with equal temperature-time conditions of the saturation process, the growth rate of the diffusion layer is 1 times higher than the known one. Tests for corrosion resistance show that compared with the known saturation in the proposed composition provides increased resistance in HC1 - steel 5 by 2.5 times, steel U8 by 1.2 times; in tyP04- steel and Y8 in 1, 3-1, times; in steel 5 V 1.8 ra, and steel U8 - 1.3 times. At that time, the diffusion layer obtained by boronation in the proposed composition is characterized by a rather high wear resistance, the treatment in the proposed composition increases the wear resistance by compared with the material strengthened in the known composition. 1 Claims of the Invention The composition for diffusion boronization of metal products containing alumina and boron oxide, is that, in order to intensify the saturation process and increase the wear and corrosion resistance of the products being processed, it additionally contains calcium carbide and cryolite at the following the ratio of components, wt.%; Boron oxide ZZ- + O Aluminum oxide 40-52 Calcium carbide 10-15 Cryolite3-5 Sources of information taken into account during the examination 1.Samsonov GV, Epik A.P. Refractory coatings. M., Metallurgists, 1973, p. 398. 2.Minkevich A.N. Chemical-thermal processing of metals. M., Mechanical Engineering, 1965, p. 90.