SU985085A1 - Method of treating steel articles - Google Patents

Description

(54) METHOD FOR PROCESSING STEEL PRODUCTS

one

This invention relates to a machine industry; instrumentation industry and precision instrumentation and can be used to stabilize the shape and size of steel products. The use of the invention is advisable in the energy engineering industry, where there are increased requirements for the reliability of the equipment and for this purpose measures are taken to reduce Q stresses resulting from cBapi operations, 1 changes in the size and shape of individual components during storage and EEC11 operation ..

There is a known method of form stabilization, j black castings, in which a product is subjected to single or multiple uniaxial tensile static static exceeding residual stresses by 3-6 times with a long-20 t processing cycle. Oh, LLC 2-0,075 h C1 j

It is not a bout of the known method that it does not provide constant CSHCTBO {dimensions of the product, since the structure retains the hurting phases that a single static tensile stress is not enough to completely remove the tetrago martensite and the decay of residual austenite.

The known method of processing hardened. steels, in which, for the purpose of tempering and accelerating the decomposition of austenite in products, during internalization they create internal compressive stresses in one direction, G2}.

The disadvantages of this method are the impossibility of completely eliminating the instability 4) and the dimensions of the product, imposing additional residual stresses, the inability to use this method for a number of steels that do not allow heating to the required temperatures ..

The closest in terms of practical essence and the achieved result to the proposed is a method of reducing residual stresses by uniform all-round compression at a pressure level without heating C 3 3. A disadvantage of the known method is that uniform all-round compression constrains the development of microplastic deformations in the material caused by shear processes and movement of dislocations, due to which incomplete elimination of residual stresses in the products occurs. In this case, an incomplete stabilization of the metastable structural components occurs, which, in the final result, does not allow the full stabilization of the geometric shapes and sizes of metal products over time. The purpose of the invention is to provide stabilization of geometric shapes and sizes. This goal is achieved by the fact that in the known method of treating steel products by compressing all-round compression in one direction is carried out by stresses, 5-6 times exceeding the strength limit of the material, and compression in perpendicular planes is cap-wound, by 1.5 -1.8 times the ultimate strength. In the proposed method, the loading of an object can be considered as the sum of all-round uniform compression by stresses equal to 1.5-1.8 (ets, and additional compression in one direction by stresses equal to 3.5-4.26 compressive stress of high level, allows to achieve almost complete reduction of residual stresses, stability of geometric shapes and sizes and, thus, almost completely eliminate the subsequent deformation of metal products in time. At the level of maximum stresses less than (5-6) 3i of the material for compression, the effect of reducing residual stresses: of the first kind and eliminating the structure of residual austenite is insufficient, since a certain activation energy is required for the complete plastic deformations of the dislocation nature to take place. -6) 6

200

60 108 660 nd

0.2

Proposed 0.2 W in compression. The application of smaller voltages does not provide completeness of effects, and large ones are not energetically favorable. The application of only one uniaxial compressive stress at such a level will lead to the destruction of products. For most metals, the Poisson's ratio is equal to 0.3, therefore, in order to avoid destruction along with the main stresses in the radial direction, compressive stresses should be applied with a value equal to 0.3 (5-6) 6c, i.e. (1.5-1.8) at the time of processing c-gall products should be sufficient for a full course of plastic strains. Example. The test specimens are shafts with a diameter of 5 mm and a length of 35 O-mm made of materials Art. 3 and 25HGSA. The shafts are made by turning and grinding, as a result of which the level of axial residual stresses of the first kind in the surface ones that have been worked on during the treatment, the layers for these materials are 25 kg / mm and 14O kg / mm, respectively. Samples are tested according to the proposed and known methods. In tests according to a known method, the pressure of all-round compression varies from 0 to 2OO kg / mm. When the pressure changes from 10O to 20O, no further increase in the positive effect of the treatment is observed, therefore, a pressure greater than 200 kg. M is not used. In tests of the proposed method, the samples are inserted into. hole rigid matrix hydraulic press with zero clearance. Such a fit is carried out by selecting the required size of the roll diameter. The axial load is created by a hydraulic press, radially due to the forces generated from the internal diameter of the rigid matrix. Comparative results of testing samples for the proposed and known method are given in the table. From the given data, it is clear that the proposed method of processing provides almost complete stabilization of the geometry of steel products. Using the proposed method of processing stapled products provides, in comparison with the known alternating loads applied to the product, the following advantages: reducing the labor intensity of processing and cost of products (by eliminating costly equipment, reducing the duration of the stabilization process and increasing the product durability, since this method there is no accumulation of damage due to cyclic loads. The application of the proposed method in instrument making p and manufacturing osishulki Hydroscope provides economic benefits in the amount of 200 thousand rubles. per year.

Claims (3)

Continuation of the Table The claims of the method of processing steel products by comprehensive compression, characterized in that, in order to ensure the stabilization of geometric shapes and sizes, compression in one direction. The stresses are carried out by stresses that are 5-6 times higher than the material strength, and the compression in perpendicular to the planes is stresses that are 1.5-1.8 times higher than the strength. Sources of information accepted in the examination during the examination 1. USSR author's certificate № - 28011, cl. C 21 D 7/10, 1972. 2. Author's testimony of the USSR No. 54398, cl. C 21 D 1/78, 1937. 3. Japanese patent number 15915, cl. 12 C 4, claimed OZ.O9.60, published. 06.10.62.