Increasing the Strength of Welded Joints of Low Alloy Steel by Ultrasonic Shock Processing

Abstract

The article investigates the effect of ultrasonic shock processing on the redistribution of residual welding stresses, the structure and the toughness of welded joints of low-alloy steel 10HSND. The results of the analysis of failures of mining equipment show that the more often the initiators of their destruction are welded joints. In this regard, one way of solving this problem is to use methods of hardening. The paper describes the methodology of research and technology of ultrasonic shock processing of welded joints of low-alloy steel. The results of studies of the effect of ultrasonic shock processing on the redistribution of residual stresses in welded joints are presented. The results of impact tests at room and negative temperature on original and treated notched specimens in the weld metal and fusion zone are shown. The results of changes of a surface layer microstructure of the weld joint areas as a result of ultrasonic shock processing are presented. It was found that the ultrasonic shock processing of welded joints of low-alloy steel 10HSND leads to a redistribution of tensile residual stresses into compressive ones. It has been established that the use of impact tool technology improves the structural properties of the work surface and a have a positive effect on the toughness of the welded joint at negative temperatures.