焊后热处理对L245NCS微合金钢焊接残余应力的影响

Effect of postweld heat treatment on welding residual stress of L245NCS microalloy steel

采用履带式电加热法对L245NCS微合金钢焊接接头进行了不同退火温度和不同保温时间的焊后热处理,采用小孔法测量焊接残余应力。结果表明,560℃退火保温3.0 h焊后热处理方案和620℃退火保温1.5 h焊后热处理方案对降低焊接残余应力均较明显,其中560℃×3.0 h焊后热处理消除残余应力的松弛率在50%左右,620℃×1.5 h焊后热处理方案消除残余应力的松弛率基本高于80%,说明延长保温时间并不能有效地降低焊接残余应力。620℃×1.5 h焊后热处理方案对于消除L245NCS微合金钢焊接残余应力更为有效。

Postweld heat treatment at different annealing temperature for different heat holding time of the welding joint of L245NCS mieroalloy steel was conducted by caterpillar electric heating. The welding residual stress was measured by the Mathar＇s method. The results show that the welding residual stress of welding joint is obviously relieved about 50% and 80% , when annealed at 560 ℃ for 3.0 h or at 620 ℃ for 1.5 h, respectively. It shows that to extend holding time can not effectively eliminate the welding residual stress, however it is more effective when annealed at 620 ℃ for 1.5 h.