吉帕级低合金高强度推土机刀板用钢NM400焊接性能研究  

STUDY ON WELDING PERFORMANCE OF NM400 FOR LOW ALLOY HIGH STRENGTH BULLDOZER BLADE

作　　者：刘丽敏[1] 王立伟[1] 闫俊霞[1] 赵天亮 Liu Limin;Wang Liwei;Yan Junxia;Zhao Tianliang(Hebei University of Science and Technology,Shijiazhuang,Hebei,050018;Hebei Installation Company,Shijiazhuang,Hebei,050018)

机构地区：[1]河北科技大学,河北石家庄050018 [2]河北省安装公司,河北石家庄050018

出　　处：《河北冶金》2020年第6期27-30,57,共5页Hebei Metallurgy

基　　金：国家自然科学基金资助项目(编号:51875168);河北省自然科学基金资助项目(编号:E2019208089)。

摘　　要：介绍了吉帕级低合金高强度推土机刀板用钢NM400的化学成分、组织及力学性能。根据低强匹配原则,通过采用80%Ar+20%CO 2混合气保护焊接工艺以及高强度GM100焊丝,研究了NM400钢的焊接性能。结果表明,在焊件开双面1/3V、2/3V形坡口、坡口角度60°、堆焊的条件下,焊接板拉伸开裂位置在焊缝部位,抗拉强度为1053 MPa、断后延伸率为15.5%;冷弯90°性能良好,无任何开裂现象;焊接接头位置-20℃冲击功≥100 J,具有良好的低温冲击韧性;焊接板厚度方向力学性能均匀,硬度值波动不明显;焊缝组织为细小、均匀的铁素体,热影响区以马氏体为主。优良的力学性能和组织可保证吉帕级低合金高强度推土机刀板用钢NM400在低温环境、土石方作业区具有良好的使用寿命和安全性能。The chemical composition,structure and mechanical properties of NM400 steel used for the high strength low alloy bulldozer blade are introduced.According to the principle of low strength matching,the welding performance of NM400 steel was studied by using 80%Ar+20%CO 2 mixed gas shielded welding process and high strength GM100 welding wire.The results show that under the condition of double-sided 1/3V,2/3V groove,groove angle of 60°and overlay welding,the tensile cracking position of the welding plate is at the weld joint,the tensile strength is 1053 MPa,and the elongation after fracture is 15.5%;cold bending 90°performance is good without any cracking;the impact energy of welding joint at-20℃is≥100 J,which has good low temperature impact toughness;the mechanical properties of the welding plate are uniform in the thickness direction,and the hardness value does not fluctuate obviously;the microstructure of the weld is fine and uniform ferrite,and the heat affected zone is martensite.The excellent mechanical properties and structure can ensure the good service life and safety performance of high strength low alloy NM400 steel,which is used for bulldozer blade,in low temperature environment and earthwork operation area.

关 键 词：吉帕级 推土机刀板 NM400 焊接 焊缝 热影响区 

分 类 号：TG457.11[金属学及工艺—焊接]