Authors: Dasam Hari Satya Sai Srinivas, V Ravi Kumar, V Vijay Kumar
Abstract: In the paper, influence of hydrogen on mechanical properties of welded joints from heat-treatable structural steel plates were investigated. The heat treatment of welded plate specimens was performed, and then the specimens were charged with hydrogen electrolytically generated from 1 N H2SO4 solution. The following studies were carried out: static tensile test, hardness investigations, macroscopic metallographic investigations as well as investigations with the use of a scanning microscope. Hydrogen embrittlement of welded joints from steel plates was revealed by a distinct decrease of ductility and a slight decrease of strength. On the basis of metallographic investigations, it was found that in a fracture region there are fine pores created by the presence of hydrogen and its displacement due to formed stresses and plastic deformation. It was shown that welded joints are susceptible to hydrogen cracking in the heat affected zone and in the fusion zone.