SU998542A1 - Method for treating steel parts - Google Patents

Description

The invention relates to mechanical engineering and can be applied to increase the wear resistance of products from low carbon steels.

The known method of heat treatment of metals includes heating the Eskalp, followed by cooling in the quenching medium 11.

Depending on the temperature and quenching environment, you can change the structure of the steel and increase the wear resistance of steel products. However, this method does not provide a complete reversal of austenite. In martensite. Sometimes the residual az sthenet is up to 30%. Cold treatment is used to more fully convert austenite to martensite.

A known method of heat treatment of an instrument, according to which, in order to increase wear resistance, cold treatment is performed by shock immersion in a liquid medium 23.

However, the processing of low-carbon steels by this method does not give positive results, since there is little residual austenite in the steel and the reserves of the wear resistance are also small.

The closest to the proposed technical essence and the achieved result is a method of processing steel parts, including hardening and cold working. The child is pre-subjected to an electrospark before cold treatment. alloying with special hardening electrodes.

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As a result of electrospark doping, the surface of the degli, from. prepared from mild steel, saturated with alloying elements AND: carbon. Subsequent treatment with cold improves the wear resistance of such parts NW}.

However, the known method is not very productive, since it is carried out in most cases manually. Tampers for automatic alloying of complex-shaped parts do not yet exist. The maximum productivity, which can be achieved, does not exceed the existing

25 installations of several square centimeters per minute.

The aim of the invention is to increase the wear resistance of parts and increase the productivity of the process.

30 processing. This goal is achieved by the fact that according to the method of processing steel parts, including heating the diffusional saturation of the surface, quenching and cold working, the diffusion saturation is carried out with a ferromagnetic ferromagnetic powder when heated in an electromagnetic field. As a result of electrodiffusion alloying, the surface of a part made of mild steel is saturated with alloying elements and carbon. In this case, a surface diffusion layer with a thickness of 0.2-3 mm is formed, which has the properties of hardening and contains alloying elements. Electrodiffusion process; In an electromagnetic field, the workpiece is placed in such a way that particles of a doping ferromagnetic powder can be placed between the center of the electromagnet and the part. The ferromagnetic powder is held at the end of the core of the electromagnet by a magnetic field and is in contact with the surface of the part. An electric current with a density of 0.5–10 A / cm is passed through the core of the electromagnet, the ferromagnetic powder and the part of the DC source, and the anode is the center of the electromagnet. As the part is rotated, the powder particles are scooped across the surface, d Tgali, herewith. at the same time, electrodiffusion of the powder material into the metal of the part takes place. Current density passing through ferro Magnetic powder determines the speed and depth of electrodiffusion doping. The current density should not exceed the critical, at which part of the piston begins to melt and sticking to the surface of the part, since this reduces the surface finish. The core of the electromagnet has interchangeable tips, the shape and size of which is chosen depending on the shape and size of the workpiece. Electrodiffusion doping is ten times more productive than electric spark doping. This method can simultaneously process a large part surface, x: above 100 cm. The process of electrodiffusional alloying can be easily mechanized and automated, since there is no rigid connection between the part and the tip of the electromagnet (ferromagnetic powder facilitates any form of the workpiece surface). Ferroboron, ferrotitanium, ferro-tungsten and other powders are used as alloying ferromagnetic powders, giving the surface of the part increased wear resistance, hardness, and corrosion resistance. After electrodiffusion doping, the component is subjected to cold treatment in a liquid medium, such as liquid nitrogen. The processing time is chosen depending on. sizes and shape details. For many machine parts, the time of electrodiffusion doping is 5–10 min, the time of cold treatment in liquid nitrogen is 1–15 min. After this treatment, their wear resistance is significantly improved. PREMIUM Detail (kingpin knuckle car ZIL), made of st.40, alloyed by electrodiffusion methods and treated in liquid nitrogen. The material of the alloying powder is ferrobor. Processing mode: part rotation speed, 250 rpm, electrodiffusion doping current 2 A / cm, operating voltage 36 V, doping time 10 min, processing time in liquid nitrogen 5 min, manufacturer-. doping 60. After electrodiffusion doping, a doped layer with a thickness of 0.3 mm was formed. Then the part was subjected to cold treatment in liquid nitrogen. The surface of the part became harder (microhardness 1200 kg / mm, and the core remained the same). Shkvorn wear resistance increased by 5 times compared with the untreated. The speed of electrodiffusion doping, depending on the shape of the parts, is 10–60, and the electric-spark rate is only 0.5; , 1.0 to him, i.e. electrodiffusion alloying is more efficient than electric spark by 10-60 times. In this case, the purity of the alloyed surface also increases by 2-3 classes. Other modes of cylindrical shape, such as shafts, half shafts, pivots, fingers and other parts made from Art.5, Art.10, Art.45 for cars, motor graders, bulldozers, self-propelled rollers, scraper , tractors and other cars. Thus, the use of the proposed method for treating steel parts can significantly increase their wear resistance, replacing expensive alloy steels used for the production of critical parts with cheaper ones: alloyed steels. The proposed method is at least 10 times more efficient than methods using electric-spark doping or chemical-thermal treatment. The introduction of electrodiffusion alloying instead of electrospark alloying or chemical-heat treatment 5 at four repair plants of Glavrasnodaravtotrans, by increasing labor productivity and increasing the wear resistance of parts, has resulted in an eco-effect 10 over 70 thousand rubles. in year. FORMUL.-invented, Method of processing steel parts, including heating, diffusion15 saturation of the surface, quenching and 2 cold treatment, about 1 ml, and so that, in order to increase the wear resistance of parts and increase the productivity of the process, diffusion saturation is carried out with a carbide ferromagnetic powder when heated in an electromagnetic field. . Sources of information taken into account during the examination 1. A. Samokhotsky; Technology of heat treatment of metals. M., TA o ioeS ei bc ™ USSR 485161, cl. C 21 D 6/04, 1972. 3. USSR Copyright Certificate 697575, cl. C 21 D 1/78, 1978.

Claims (1)

Claim A method of processing steel parts, including heating, diffusive saturation of the surface, hardening and cold treatment, characterized in that, in order to increase the wear resistance of the parts and increase the productivity of the process, diffusion saturation is carried out with 5 carbide ferromagnetic powder during heating in an electromagnetic field.