摘要
对冷拉成形后的ER70S-6焊丝进行弯折试验,结果为焊丝发生脆断现象。采用宏观观察、化学成分分析、金相检验和不同热处理工艺后微观分析等方法对焊丝弯折脆断的原因进行分析。结果表明:ER70S-6焊丝弯折脆断的主要原因是其存在淡黄色马氏体与贝氏体复合组织(MB),同时冷变形过程中的加工硬化也促进了弯折脆断的发生;淡黄色M-B非平衡组织是钢盘条在精轧后控冷工艺不满足条件产生的;在控冷阶段,保温罩内盘条温度冷却到A1点(700℃)时,控制调节部分风机开口率以提升过冷度,减小珠光体片层间距,并保证盘条出罩温度不大于600℃,可以提高材料的塑性,并防止产生M-B组织。
The bending test of ER70S-6 welding wire after cold drawing was carried out,and the brittle fracture phenomenon of welding wire was found.The causes of bending brittle fracture of welding wire were analyzed by means of macroscopic observation,chemical composition analysis,metallographic examination and microanalysis after different heat treatment processes.The results show that the main reason for the bending brittle fracture of ER70S-6 welding wire was the existence of pale yellow martensite and bainite composite structure(M-B),and the work hardening during cold deformation also promoted the occurrence of bending brittle fracture.The pale yellow M-B non-equilibrium microstructure was caused by the controlled cooling process that did not meet the conditions of ER70S-6 steel wire rod after finishing rolling.In the controlled cooling stage,when the temperature of the wire rod in the insulation cover was cooled to A1 point(700℃),controlled and adjusted the opening rate of the fan to improve the supercooling degree,reduced the pearlite lamellar spacing and ensured that the temperature of the cover was not more than 600℃,the plasticity of the material could be improved and the generation of M-B could be prevented.
作者
田伟
王兴
雷洋
李娜
林生秀
TIAN Wei;WANG Xing;LEI Yang;LI Na;LIN Shengxiu(Shaanxi Steel Group Industrial Innovation Research Institute Co.,Ltd.,Hanzhong 723000,China)
出处
《理化检验（物理分册）》
CAS
2024年第2期60-63,共4页
Physical Testing and Chemical Analysis(Part A:Physical Testing)
关键词
ER70S-6焊丝
弯折脆断
M-B复合组织
控冷工艺
显微组织
ER70S-6 welding wire
bending brittle fracture
M-B composite structure
controlled cooling process
microstructure
