SU648297A1 - Method of making rolled sections of bearing steel - Google Patents

Description

(54) METHOD FOR OBTAINING A GRANULAR ROLL FROM A BEARING STEEL

The invention relates to the field of metallurgy, more specifically to the processing of metals by pressure, and can be used in modern factories specializing in the production of rolled steel from bearing steels. There is a known method for producing rolled steel from bearing steel, consisting in the fact that ingots and rolling blanks are heated in process furnaces or heating wells. The temperature of the hot end is 750-820 ° C. The metal is heated for 5-6 hours. The heating temperature of the bearing steel ingot during rolling is 1160-1180 ° C. The ingot rolling is carried out according to the reduction modes 1 However, the billets produced in this way are of poor quality, because the metal is exposed. high temperatures for a long time, decarburized to a considerable depth. The surface decarburized layer must be mechanically worn. Also known is the method of preparation. bearing rolling, in which the heating of the metal is carried out in mechanical furnaces to a temperature of 1180 1200 C 2. To reduce the degree of metal decarburization, the residence time of the billet at a temperature above the minimum is possible. Rolling blanks for finished rolling is carried out in the following temperature range: start of rolling 1160–1180 ° C, end of rolling 900–950 ° C. In this range of bearing Xp, steel TsH15 is characterized by rather high ductility, which allows EXECUTE rolling with relatively large reductions in existing roll calibration systems. Then the rolling is subjected to annealing, after which its microstructure consists of uniformly distributed fine-grained perlite with a carbide mesh. The resulting pryucate is machined to remove the decarburized layer. However, this method of obtaining bearing steel has significant drawbacks from the point of view of obtaining high-quality products in terms of the size of the decarburized layer, the carbide mesh, and grain size.

The purpose of the invention is to improve the quality of rolled steel from bearing steels due to an increase in grain size and a decrease in balance over the carbide mesh.

This is achieved by the fact that in the known method of producing long-rolled steel from bearing steel, which includes heating the metal, rolling the section and heat treatment, the finished steel is obtained from a previously prepared rolled strip, which is subjected to accelerated heating to a temperature of 790-870 ° C and deformation at this temperature.

Previously received and recorded: a riot roll, which has a reduced ball size in the grain size h (the power meter on the size of the carbide mesh, serves as a reboot for € 1). Acting as a heating device, the ElektroIlNiNGT or induction preheater is used. Here the Metal is heated to: temp. 79.0-870 s: after trimming, on the front section of the front of the kojts. at the same time, when it is pressed and simultaneously potassium: boar; since the heating temperature of the metal is 790-87 ° C and the heating rate is large enough, the decarburization process is practically Mecta,

Such a temperature is chosen so that the temperature in the last pass is within 76 ° F-40 ° C. This ensures that the grain size is within y-10 points.

The field of deformation of the metal entering the installation to remove the eye and then to accelerate the cooling of the car in a stream of moist air supplied under pressure. An increase in the rate of cooling of the rolled stock from the temperature of the end of the rolled stock to 700 ° C makes it possible to obtain a carbide mesh in the form of thin broken sections with a length of no more than 0.009 mm, corresponding to a point of 1.

Then the peal is heated to a temperature of 790-810 0 for conducting softening annealing, wound up and slowly cooled to a temperature of 700 s in water in air and in the vapor-air mixture, and then in air.

Claims (2)

Invention Formula The method of producing section steel from bearing steel, including metal heating, rolling, finishing and heat treatment, is also distinguished by the fact that, in order to improve the quality of rolled metal, the pre-irradiated rolled sheet is subjected to accelerated heating to 790-870 C and rolled at this temperature. Sources of information taken into account in the examination 1, Korolev M.I. and others. Production of BEARING steel. M., 1960, with. 212. ,, 2. Sheftel N.I. Technologists production rolled. M., Metallurgists, 1976, p. 247.