SU711126A1 - Method of thermal mechanical treatment of steel articles - Google Patents

Description

one

The invention relates to metalworking, in particular to the processing of metals and alloys by plastic deformation in combination with heat treatment, and may find application in the processing of parts, bodies of rotation, flat and shaped surfaces of parts.

The known method of thermomechanical processing, combining the process of heating and plastic deformation by processing a stream of heated fraction (1).

A method of thermomechanical treatment is also known, including austenization, deformation and cooling, in which cold plastic deformation of the surface 2 is additionally performed.

The known methods allow to increase the strength properties of the products, however, they do not affect the process of cooling the parts when their properties are formed during the quenching process.

A known method for the thermomechanical treatment of metal products, including heating and cooling by a gas stream, varying from supersonic to subsonic speed, contains sputtered liquid bodies and solid matter 3.

The method makes it possible to adjust the structure of products while simultaneously hardening the surface layer, but does not provide a martensitic structure for steels with a martensitic turning point below 0 ° C. In addition, the creation of a supersonic gas flow velocity complicates equipment and impairs sanitary conditions due to the presence of noise.

Closest to the present invention is a method that includes heating products for quenching and cooling, consistent with the deformation process with steel shot 4 |.

The disadvantage of this method is a low level of physical and mechanical properties, since the required structure of the products is not ensured. In addition, in the process of multiple use of steel shot, there have been marked .1.1 cases of its brittle fracture, which adversely affects the quality of the processed products (there are: 1 galls, scratches, etc.), as a result of which the durability of products operating under conditions bending with torsion.

The purpose of the invention is to improve the physical and mechanical properties of products.

This goal is achieved by the fact that in a known method involving heating metal products and cooling combined with plastic deformation by a fraction, cooling and plastic deformation are carried out with ice balls or shot with an ice shell. The mass and speed of impact of ice balls are selected so that their kinetic energy is sufficient to achieve the desired degree of deformation. During the impact, due to the high temperature of the heated surface, the ice ball melts quickly and cools it. Since the process of melting and evaporation requires a large amount of heat, the cooling of the surface layer proceeds rapidly. Thus, the proposed method allows to combine the plastic deformation of the heated surface layer with its rapid cooling.

In addition, for steels whose martensitic transformation end temperature is below zero, in order to reduce the amount of residual austenite, cooling to temperatures below zero is required. Processing with ice balls allows us to solve this problem, since the deformation increases the martensitic transformation point, and with cooled ice, it contributes to the decomposition of residual austenite.

For more intense cooling, frozen beads obtained from 8-12% aqueous solutions of NaCl and NaOH can be used.

The method is carried out as follows.

The part is mounted in the centers of, for example, a lathe, and the shot-measuring device is attached to the tool holder holder. The part is rotated and the inductor is heated to a predetermined temperature, then the shot is processed. After processing, stop the rotation and squeeze the part from the centers.

Example. Three batches of parts (10 pieces each), made of steel 45 with a diameter of 30 mm and a length of 250 mm, are processed.

In the first batch, the parts are treated, including heating to 830 ° C, plastic deformation by a jet of shot under the pressure of compressed air Scr / cm. The tempering is performed at 250 ° C, followed by air cooling. In the second batch, the parts are processed by the proposed method, first heating them to the same temperature as in the first case (830 ° C), then the inductor is turned off and the part is subjected to plastic deformation and simultaneous cooling with ice balls. In the third batch, the parts are also processed according to the proposed method, however, an iron shell with an ice shell is used. Vacation modes in all three batches are identical.

Processing modes are given in Table. one.

Table

 The diameter of the ice balls when processing the second batch of parts is chosen from the condition of equality of kinetic energies when working with iron-shot and ice balls. The same condition is observed when choosing the diameter of a fraction with an ice shell. In that

In this case, the diameter of a cast iron shot is 1.5 mm, the calculated thickness of the ice shell is 1 mm.

Claims (4)

In tab. Figure 2 shows the average hardness of the Vickers surface layer HV, o. In comparison with the known, the use of the proposed method allows to increase the physicomechanical properties of the products, to obtain a martensitic structure even for steels with a martensitic transformation point below 0 ° C, to reduce the cost of the process in the case of processing with ice balls only. Claims of the method of thermomechanical treatment of steel products, including heating and cooling, combined with plastic table 2 formation of crabs, characterized in that, in order to improve the physical and mechanical properties of products, cooling and plasticity. Some kind of deformation is carried out with ice balls or shot with a shell of ice. Sources of information taken into account in the examination 1. USSR author's certificate number 68605, cl. From 21 D 7/06. 1946. 2. USSR author's certificate number 321544, cl. From 21 D 7/14, 1970. 3. USSR author's certificate number 395445, cl. From 21 D 1/7, 1970. 4. Japan patent number 12337, cl. 1OA, 20.1, 1967.