基于插销试验法Q690高强钢焊接冷裂敏感性研究  

Study on Welding Cold Cracking Susceptibility of High Strength Steel Q690 Based on Implant Test

作　　者：朱双春 曹莹 吉荣亮 ZHU Shuangchun;CAO Ying;JI Rongliang(Jiangsu College of Engineering and Technology,Nantong 226006,China;Harbin Welding Institute Limited Company,Harbin 150028,China)

机构地区：[1]江苏工程职业技术学院,江苏南通226006 [2]哈尔滨焊接研究院有限公司,黑龙江哈尔滨150028

出　　处：《热加工工艺》2023年第23期45-49,共5页Hot Working Technology

基　　金：江苏省高等教育教改研究课题项目(2021JSJG559);南通市基础研究与民生科技计划指导性项目(JCZ21081);江苏工程职业技术学院教学改革研究课题项目(GYJY202109)。

摘　　要：应用插销试验法研究Q690高强钢手工焊条焊接的冷裂敏感性,评估预热温度和焊接线能量对Q690临界断裂应力的影响。结果表明,采用线能量1.48 kJ/mm、不预热焊接时,临界断裂应力只有650 MPa,而采用线能量1.48kJ/mm、预热75℃焊接时,临界断裂应力提高到930 MPa,这是由于预热降低了焊接接头低温区的冷却速度,改善了粗晶区组织,提高了抗冷裂性能。采用线能量3.08 kJ/mm进行焊接,不预热时临界断裂应力为870 MPa,预热75℃情况下临界断裂应力为850 MPa,其热影响区粗晶区均为马氏体和贝氏体的混合组织,粗晶区脆化程度低,一定程度上提高了抗冷裂性能。但由于采用的线能量较大,特别是在预热情况下,热影响区软化区软化程度加重,降低了焊接接头的临界断裂应力。The implant test was used to study the cold cracking sensitivity of manual electrode welding of Q690 high strength steel,and the influence of preheating temperature and welding line energy on the critical fracture stress of Q690 was evaluated.The results show that the critical fracture stress is only 650 MPa when the line energy of 1.48 kJ/mm is used for non preheating welding,while the critical fracture stress is increased to 930 MPa when the line energy of 1.48 kJ/mm is used for preheating welding at 75℃.This is because preheating reduces the cooling rate of the low temperature zone of the welded joint,improves the microstructure of the coarse grain zone,and improves the cold crack resistance.When the line energy of 3.08 kJ/mm is used for welding,the critical fracture stress is 870 MPa without preheating and 850 MPa with preheating at 75℃.The coarse grain zone in the heat affected zone is a mixture of martensite and bainite.The embrittlement of the coarse grain zone is low,which improves the cold crack resistance to some extent.However,due to large line energy,especially under preheating,the softening degree of the softening zone in the heat affected zone is increased,the critical fracture stress of the welded joint is reduced.

关 键 词：低合金高强钢 焊接冷裂纹 插销试验法 

分 类 号：TG406[金属学及工艺—焊接]