Influence of modulation on the properties of low-carbon high-strength steel welded joints, produced by manual arc welding

摘要

Features are studied of thermal cycles of cooling of the metal of the heat-affected one (HAZ), of formation of the structure and properties of welded joints of low-carbon alloyed steels, as well as their resistance to delayed fracture in manualelectric-arc welding with modulated current (MAW-MC). It is shown that parameters changing in MAW-MC, compared to the stationary process of manual-arc welding (MAW) allows slowing down the process of the HAZ metal cooling in the low-temperature region,and promotes lowering to 25 % of the concentration of diffusible hydrogen in the deposited metal. MAW-MC results in refinement of the primary structure of the weld metal (to 40 %) and reduction of its maximal microhardness (to 12 %). This promotes animprovement of its performance (to 30 %) and reduction of delayed fracture (to 10 %).