Microstructure and Properties of Dissimilar Metals Welded Joint of New Tamping Tine Steel for Railway's Maintenance

摘要

The microstructure and mechanical properties of welded joint between 20SiMn3NiA and 40CrNiMo were studied by carbon-dioxide arc welding. According to the principle of low strength matching of dissimilar metals weld, the strength of the welded joint is 60% of that of 20SiMn3NiA, and the impact toughness reaches 60% of parent metal's toughness. Also the impact ductility is high enough to meet the applications of divided structure tamping tine when the strength of welded joint is properly lower than that of 20SiMn3NiA. Furthermore the performances of fusion zone are worse than welded joint and heat-affected zone for martensitic brittle layer was formed during the welding of 20SiMn3NiA and 40CrNiMo.