Keyword: «residual welding stresses»

The features of the stress state, physical-mechanical and structural properties of welded joints of structural steels 09G2S and St3sp, made at low climatic temperatures, are studied. Welded samples were obtained by manual arc welding using domestic electrodes UONI-13/MOROZ, HOBEKS-K-54, LB 52TRU. During the research, pulsed arc welding was tested in comparison with the traditional method of direct current welding. When welding in the cold, an increase in the level of tensile residual welding stresses by an average of 40 ... 50% is observed compared with welding at room temperature. Features of the structure and mechanical properties during welding at negative temperatures are revealed.

Examples of destruction of welded joints of sections of main gas pipelines in Yakutia under the influence of fields of residual welding stresses are considered. The results of experimental studies of residual stress fields of welded joints of plates made by arc welding under conditions of low climatic ambient temperatures are discussed. The mechanism of the influence of residual stresses on the occurrence of additional plastic deformations in the zones of welded joints after welding under conditions of low climatic temperatures is presented.

The study is devoted to the urgent problem of residual welding stress management in welded joints made of low-alloy steel 10XSD. The effect of ultrasonic shock treatment (UO) on the redistribution of HP after welding at room and subzero temperatures has been experimentally studied. It is established that after welding, significant tensile stresses are formed in the seam area, the level of which increases during low-temperature welding. It is shown that UO effectively transforms tensile stresses into compressive stresses, which contributes to an increase in the fatigue life of joints.