碳和碳当量对Q690高强结构钢焊接性能的影响  

Effect of Carbon and Carbon Equivalent on Weldability of Q690 High-Strength Structural Steel

作　　者：杨浩 黄朋 李丽 曲锦波 YANG Hao;HUANG Peng;LI Li;QU Jinbo(Institute of Research of Iron and Steel,Shasteel,Zhangjiagang Jiangsu 215625,China)

机构地区：[1]江苏省(沙钢)钢铁研究院,江苏张家港215625

出　　处：《上海金属》2024年第5期17-21,32,共6页Shanghai Metals

摘　　要：通过热影响区最高硬度试验和对接焊试验,研究了碳含量和碳当量对屈服强度690 MPa级高强结构钢焊接性能的影响。结果表明:在焊接热输入量小、热影响区冷速大的情况下,热影响区组织主要为马氏体,热影响区最高硬度更多受碳含量的影响而非碳当量,碳含量低(碳质量分数0.077%)、碳当量高(碳当量0.62)的试验钢热影响区最高硬度较低,冷裂倾向较小;在焊接热输入量大、热影响区冷速小的情况下,碳当量高的试验钢淬透性更高,热影响区形成板条贝氏体,表现出更好的低温韧性;而碳当量低的试验钢淬透性较低,热影响区形成粒状贝氏体,低温韧性较差。Through the maximum hardness test in heat-affected zone and butt welding test,the effects of carbon content and carbon equivalent on the weldability of the high-strength structural steel with yield strength of 690 MPa were investigated.The results showed that(a)under the condition of small welding heat input and large cooling rate in the heat-affected zone,the micostructure of the heat-affected zone was mainly martensite,and the maximum hardness of the heataffected zone was more affected by carbon content than carbon equivalent;(b)the tested steel with low carbon content(carbon mass fraction of 0.077%)and high carbon equivalent(carbon equivalent of 0.62)had a lower maximum hardness in the heat-affected zone and a smaller tendency to cold cracking;(c)under the condition of large welding heat input and small cooling rate in the heataffected zone,the tested steel with high carbon equivalent exhibited higher hardenability and lath bainite in the heat-affected zone,thus showing better low-temperature toughness,while the tested steel with low carbon equivalent exhibited lower hardenability and granular bainite in the heat-affected zone,thus showing poor low-temperature toughness.

关 键 词：Q690高强钢 焊接 碳当量 组织 性能 

分 类 号：TB31[一般工业技术—材料科学与工程] TG406[金属学及工艺—焊接]