SU779422A1 - Method of strengthening treatment of welded joints - Google Patents

Description

one

Strengthening treatment is intended for use in the manufacture of welded frame structures subjected in operation to a large number of loading cycles, which can cause fatigue damage.

The field of application of such structures, for example, electric locomotive and diesel locomotive building, is also applied to other branches of the mechanical engineering industry 10, which manufacture frame structures for transport vehicles.

Methods are known for increasing the fatigue strength of welded joints of large-sized structures, on the basis of which intensive surface plastic deformation is used, which ensures high stability of the strengthening effective f, 2 and 3.20.

Here, the reinforcement is carried out by:

rolling between two rollers;

coinage with single and multi-core tools; 25

shot blasting.

In these methods, residual stresses are induced in the areas of stress concentrators limiting fatigue strength, the depth of the SO is

which exceeds the depth of the field of concentration of operating stresses, and thereby neutralizes the stress concentrators. The same effect is achieved by the explosion of charges located above the stress concentrator.

To increase the fatigue strength of welded structures, electric arc treatment of the transition zone of the welded joint is used, the effect of which is to reduce the concentration of stresses and neutralize internal metal defects by melting in a neutral environment 4

Closest to the present invention is a treatment method, which includes the processing of a multi-sided hardener after an argon-arc treatment and is a reliable means of increasing the fatigue strength of dynamically loaded frame structures 5.

However, due to the simultaneous shock contact of the needles (strikers) of the treated surface of the hollow structure, excessive noise is created, the harmful effect of vibrations on the operator's hand.

The purpose of the invention is to eliminate the effects that affect the hand of the operator, reducing noise during processing and increasing the durability of wearing parts while maintaining fatigue strength values. . This goal is achieved by the fact that, after argon-arc reflow, refining shot blasting is carried out at a fraction of 70 degrees to the treated surface. Example. 10 box-section beams with dimensions (LI IZ of M16S sheet steel with a thickness of 14 (horizontal sheet) and 12 mm (vertical sheet) were made. The beams were welded with a semiautomatic machine in carbon dioxide medium in 20 mm thick plates. After argon-arc treatment, welded the joints were subjected to blast cleaning with blasting at a limited fraction angle of not less than 76. At the resonant vibration stage, the following estimates of endurance limits were obtained with a symmetric cycle: 887, 1000, 1083, 1087 kgf / cm. Combined treatment ensured There is a stable I significant improvement in resistance to cyclic loads with improved sanitary conditions of the pile and increased productivity. Fbryula of the Invention Method of strengthening treatment of welded joints by argon-arc refining of the weld zone with subsequent plastic surface deformation, m and ch u and with the fact that, in order to improve working conditions and increase productivity, after the product is melted, it is subjected to blast cleaning at shot angle to batting surface Not less than 70 °. Sources of information taken into account in the examination 1.ABTOjicKOe USSR certificate № 390890, cl. At 23 K 28/00, 1972. 2. The author's certificate of the USSR 183790, cl. B 24 B 39/00, 1966. 3. USSR author's certificate No. 318467, cl. B 24 B 39/00, 1970. 4. USSR author's certificate No. 197804, cl. B 23 C 2: 8/00, 1967. 5. Sat. Improving the reliability of welded structures of rolling stock, Proceedings TSNIIMPS, vol. 485, M., 1976, pp. 40-46. .

Claims (1)

Claim A method of hardening treatment of welded joints by argon-arc fusion of the weld seam aeon followed by surface plastic deformation, and searching for the fact that, in order to q improve working conditions and increase productivity, the product is subjected to refining after fusion shot-blasting at an angle of incidence of the shot to the work surface of at least 70 °.