Influence of Severe Dynamic Action on Phase and Structural Transformations in a Metal of Welded Joints.

Optical and scanning electron microscopy, as well as X-ray diffraction analysis, have been used to study the structural changes in the welded joints of steel structures subjected to a local severe dynamic action. It has been shown that after welding, a structure consisting of martensite, δ ferrite, and metastable austenite is formed in the weld metal. The subsequent severe dynamic action leads to a strengthening of the weld metal, which is caused by the transformation of metastable austenite into strain-induced martensite. [ABSTRACT FROM AUTHOR]