960MPa级工程机械用钢焊接性能试验研究

Study on the welding performance testing of 960 MPa grade machinery steel

通过连续冷却转变曲线的绘制、焊接冷裂纹敏感性试验以及从800℃冷却到500℃的时间(t8/5)对焊接粗晶热影响区(CGHAZ)韧性的影响等方法,系统评价了一种960 MPa级工程机械用钢的焊接性能。结果表明:工程上配套使用GHS-90实心焊丝,在φ(Ar)80%+φ(CO2)20%混合气体保护下焊接,需将该钢板预热至200℃以上才能避免焊接冷裂纹倾向(钢板厚度为20 mm);t8/5>20 s后,粗晶区韧性严重降低;通过制定合理焊接工艺可满足960 MPa强度级别的工程使用要求。

The welding performance testing of 960 MPa grade machinery steel was systematically investigated by following methods： drawing the curve of CCT,testing the cold cracking sensifivity of welding and effect of the cooling time from 800 ℃ to 500 ℃（t8/5） on toughness variation of the CGHAZ.The results showed that,the cold cracking propensity of welding could be avoided by raising preheating temperature to more than 200℃ in engineering （plate thickness 20 mm）,that was compatible with the solid wire GHS-90 for φ（Ar） 80%＋φ（C02）20% shielded arc welding;the toughness variation of the CGHAZ was rapidly decreased while the t8/5 was up to 20 s;though made the reasonable welding process,the 960 MPa grade machinery steel could be used in engineering field,successfully.