SU804715A1 - Method of producing local titanium coatings on steel and cast iron articles - Google Patents

Description

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The invention relates to acquisitions, local diffusion coatings on steels and cast iron and can be used in many areas of the industry, such as chemical, non-ferrous and ferrous metallurgy, in the automotive industry, shipbuilding, etc.

There is a known method for producing local titanium coatings, where the threaded tips of drill pipes are coated with a special paste containing the alloyed titanium compound jTl.

The disadvantages of this method are the low processability of the process associated with multi-operational, i.e. the need to prepare a paste using special equipment for doping, applying it to the alloying sites and drying before the process of direct thermal diffusion saturation, as well as the impossibility of obtaining dense coatings of large diffusion thickness of titanium carbide on products made of carbon steel and cast iron and its diffusion to the surface leads to the formation of a layer of.

titanium carbides, which creates a barrier that worsens the diffusion of titanium deep into the metal. In addition, a calcified sublayer is formed, reducing the mechanical strength of the coating.

There is also known a method in which it is possible to obtain diffusion local coatings using protective coatings on carbonaceous stained iron and cast iron, where the issue of stabilizing carbon is reapplied by pre-applying an aluminum layer and its diffusion into the metal during isothermal annealing at 930-980 ° C.

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The disadvantages of this method are its multi-operability (pre-deposition of aluminum, vacuum annealing with isothermal exposure, protection of parts, not

0 subject to hardening with special protective coating, the need to prepare alloying mixtures and protective coating, cleaning products from

5 process waste), as well as increased consumption of electric power due to the need for electric arc metallization, diffusion saturation of aluminum and reheating for thermal diffusion titanation

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and also because of the low thermal conductivity of powdered doped mixtures. The purpose of the invention is to improve the process technology and reduce energy consumption.

The postsynded goal is achieved by the fact that the process of obtaining local titanium coatings on the protected surface is carried out from prespecified and & x samples from titanium powder Fe, ad 0.18–0.63 mm, repeating by the configuration of the protecting surface, spaced from it at a distance of 0.8–1.0 mm with a layer of aluminium powder worn on them and 0.1–0.15 mm thick to the surface, with another place of local protection of the product,

Thermal diffusive saturation is carried out in vacuum 950-1050 С and delivery is 4-6 h.

Example. Essentially prepared by the method of extrusion and subsequent sintering of a for1 titanium powder fraction of 0.18-0.63 mM, repeating the configuration of the alloyed surfaces. The thickness of the walls of the molds is not 1 | 5 mm. Then, on the surface of the mold, with a place of local -aaite Tis izleeln, put

A layer of aluminum powder GOST 5494-50 with a brush manually or automatically and put in easy contact with the local protection site. For example, when protecting seats on shafts, a sleeve-shaped form is put on the shaft with a layer of aluminum powder applied on its inner surface. Products with a form are placed in a retort, they are evacuated (vacuum depth to 1-10- - 1/10-mm Hg) and the temperature is raised to 950-1050 ° C. Isothermal exposure at this. temperature for 4 and 5 hours provides a layer of titanium carbide on steel U 9 with a thickness of 45 and 60 microns, on cast iron SCH 12-28 with a thickness of 35 and 55 microns. Local doping of low-carbon steels, for example steel 3, according to the proposed mode, allows to obtain a diffusion layer of titanium with a thickness of 30-40 µm with a titanium concentration up to 70%. This is ensured by the positive effect of aluminum in the process of steel alloying with titanium. The effect of the size of the titanium powder fraction and the distance from the hardened surface to the mold on the results of processing by the proposed method are presented in the table.

As can be seen from the tables, it is advisable to carry out the process from the titanium forms of the fraction — 0/63 + 0.18, with a distance of 14 OX at the minimum distance from the surface being treated. Increasing the distance from 1.0 to 1.5 mm reduces the depth of the diffusion layer by 2-3 times. The thickness of the aluminum nyftpat layer applied with a brush or by dipping in powder is about Qfi v не n. "Does not constitute a complex operation.

The proposed method allows to obtain a local titanium diffusion coating on steels and cast irons and to carry out multiple use of alloyed titanium forms. It is especially effective for sauiCMTe large-size} shh parts with the use of nyuvklatuE, when 20-30 forms provide local protection of parts for months or a number of years.

formula of ethen

The method of obtaining local titanium coatings on steel products

and cast irons, including heating to the processing temperature and holding at that temperature in the presence of titanium, characterized in that, in order to increase the processability of the process and reduce energy costs, they are prefabricated by pressing and sintering a titanium powder form with a fraction of 0.160, 63 mm, repeating the configuration the surface of the mold is locally applied a layer of aluminum powder with a thickness of O, 1-0.15 mm, then the form is installed on the product with a gap of 0.8 IjO mm, combining space with a layer of aluminum mini howl powder with portions on the articles to be protected, and heat is performed.

Sources of information taken into account in the examination

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1. SpCP author's certificate No. 389173, cl. C 23 C 13/00, 1977.

2. Authors certificate of the USSR, position No. 2361085, cl. C 23 C 9/02, 1978.

Claims (1)

Claim A method for producing local titanium coatings on steel and cast iron products, including heating to a processing temperature and holding at this temperature in the presence of titanium and sintering the mold from a titanium powder of a fraction of 0.180.63 mm, repeating the configuration 10 of the machined surface, a layer of aluminum powder 0.1-0.15 mm thick is locally applied to the inner surface of the mold, then the truss is set pour on the product with a gap of 0.81.0 mm, combining places with a layer of aluminum * 5 mini powder with areas on the products to be protected, and carry out heating.