SU368336A1 - - Google Patents

Description

METHOD OF THERMOMECHANICAL SURFACE

one

The invention relates to the field of thermomechanical processing of metals and alloys.

There is a method of thermomechanical surface treatment, including heating, plastic deformation of austenite in the process of isothermal exposure and cooling, which provides improved mechanical properties of the surface.

The purpose of the invention is to increase the complex mechanical properties of products made of steel and alloys. To this end, the surface of the product, previously subjected to high-temperature or low-temperature thermomechanical processing, is rolled at room temperature, deforming the hardened layer with martensitic or bainitic structure. The cold deformation of martensite or bainite causes a significant increase in the strength characteristics, which additionally increase in the process of subsequent tempering as a result of deformation aging. The combination of the processes of deformation and aging of a supersaturated solid solution can be achieved by carrying out a warm deformation at optimum temperatures in the range of 20-500 ° C. Cold or heat, surface deformation can be performed after the end of cooling using the same attachment 1 ALL-1 I PDTENT-TECHNOLOGY

PROCESSING

BIBPIOTRKD I

2

Compounds that were deformed in the austenitic state.

The method is carried out as follows.

Steel 40XH is heated by a special inductor with continuous rotation of the part up to 8Ш-880 С to a depth of 3-5 mm, rolled with a roller at this temperature and quenched to martensite. After tempering, the part is rolled around the roller at room temperature and then again subjected to tempering at a temperature not exceeding the first tempering temperature, i.e. 200 ° C. After this treatment, the contact endurance limit of the steel rises by 15-20% compared to the limit endurance of the same steel, processed by a known method, and the durability in the field of limited endurance increases by 2-3 times. The recommended specific pressure during the run-in is in the range of 50-120 kg / mm depending on the tempering temperature carried out before the run-in. If it is necessary to obtain higher plastic properties of the surface, the run-in is carried out at an elevated temperature in the range of 200-500 ° C. After the warm deformation of martensite (or bainite), the final release is necessary. Deformation of martensite (or bainite), then 3 with a small degree (from 0.5 to 2-3%) leads to a sharp increase in the yield strength, increase in strength, while maintaining sufficient ductility. As a result of increasing the strength properties of the surface, the fatigue strength of the part as a whole increases, especially in such working conditions, when the reinforced layer is subjected to contact loads. An additional increase in the yield strength, strength and endurance is achieved during post-deformation release, during which the deformation aging of martensite (or beiite) takes place. 4 Subject of the invention 1. A thermomechanical surface treatment method, including heating, plastic deformation during an isothermal shutter in the austenitic state, and cooling, characterized in that, in order to increase the strength characteristics, after cooling, surface plastic deformation is carried out, 2. The method according to Claim 1, characterized in that the plastic deformation is carried out at 20-500 ° C.