A517Q齿条钢的焊接性

Weldability of A517Q rack steel

通过斜Y坡口焊接裂纹试验、焊接热影响区最高硬度试验和焊接接头力学性能试验,系统地研究了A517Q齿条钢的焊接性.结果表明,在拘束焊接时,A517Q齿条钢的焊接冷裂纹敏感性随钢板厚度由30 mm增大至60 mm而增大;提高预热温度有助于降低该钢的焊接冷裂倾向和热影响区的淬硬程度.177.8 mm厚A517Q齿条钢板的焊接接头具有高强度和高韧性,能够满足使用性能要求;焊接热影响区的显微组织以低碳板条马氏体和板条贝氏体为主,该区硬度明显高出焊缝区和母材区,淬硬倾向较大,存在一定的冷裂风险.

The weldability of A517 Q rack steel was investigated systematically by means of oblique Y-groove cracking tests,maximum hardness tests on the heat affected zone( HAZ)and the mechanical property tests of welded joint. The results showed that under the restraint condition,the cold crack susceptibility of A517 Q weld was increased with the thickness of tested plates increasing from 30 mm to 60 mm. Raising preheating temperature contributed to the reduction of cold crack tendency of steel and the hard level of HAZ. The welded joint of 177. 8 mm thick A517 Q rack steel plate exhibited high strength and toughness,meeting the requirements of usage. The microstructure of HAZ mainly consisted of lath-like martensite and lath-like bainite. The hardness of HAZ apparently exceeded weld metal zone and the parent metal,presenting a high harden tendency and a certain risk of cold cracking.