JG590钢的焊接冷裂纹敏感性

Weld Cold Cracking Sensitivity of JG590 Steel

采用插销实验、斜y形坡口焊接裂纹实验和焊接热影响区最高硬度实验对厚度30 mm的JG590钢板的焊接冷裂纹敏感性进行了研究,分析了插销试件的断口和显微组织,以斜y形坡口焊接裂纹实验结果为基础,通过理论计算得到了JG590钢在不同焊接线能量、不同焊接材料情况下的临界预热温度和临界冷却时间。结果表明:采用低氢HS-60实芯焊丝,在一般拘束条件下,可以不预热,而在拘束较苛刻的条件下,预热温度应不低于100℃;使用较高扩散氢含量的GFM-60金属粉芯焊丝时,在一般拘束条件及较苛刻拘束条件下,预热温度应分别不低于50℃和125℃。

The cold cracking sensitivity of 30 mm thickness JG590 was studied using the implant test, the Y-slit crack test and the HAZ maximum hardness test. The HAZ microstructure and fracture morphology of the implant samples were analyzed. On the basis of the result of the Y-slit crack test, the critical preheat temperature and critical cooling time （t8/scr） of JG590 under the condition of different heat input and welding material were determined by theoretic computation. The results indicate that under the condition of general constraint, preheating is not necessary when the low diffusible hydrogen content welding wire of HS-60 is used ,whereas a low preheating temperature of 50 ℃ is required in the case of a relatively high diffusible hydrogen content wire GFM-60 , and in the case of severe constraint, as in the case of Y-slit crack test, the critical preheat temperature is respectively 100 ℃ for HS 60 and 125 ℃ for GFM-60.