屈强比对DP540双相钢闪光对焊接头变形行为的影响  

Effect of Yield-to-Tensile Strength Ratio on Deformation Behavior of Flash Butt Welded DP540 Dual-phase Steel Joint

作　　者：王舒扬[1,2] 丁凯 霍世宗[3,4] WANG Shuyang;DING Kai;HUO Shizong(R&D Center,Baoshan Iron&Steel Co.,Ltd.,Shanghai 201900,China;State Key Laboratory of Development and Application Technology of Automotive Steels,Shanghai 201900,China;State Key Laboratory of Advanced Special Steel,Shanghai Universisty,Shanghai 200444,China;School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]宝山钢铁股份有限公司中央研究院,上海201900 [2]汽车用钢开发与应用技术国家重点实验室,上海201900 [3]上海大学省部共建高品质特殊钢冶金与制备国家重点实验室,上海200444 [4]上海大学材料科学与工程学院,上海200444

出　　处：《上海金属》2023年第1期68-72,78,共6页Shanghai Metals

摘　　要：对屈服强度不同、厚度为6 mm的DP540双相钢板进行了闪光对焊。检测了焊接接头的显微组织和拉伸性能。结果显示:屈服强度为338 MPa的焊接接头屈强比为0.62,拉伸试样断裂在粗晶区;屈服强度约为450 MPa的焊接接头的屈强比为0.8~0.9,拉伸试样断裂于母材;屈强比较低的接头母材组织粗大且马氏体呈大块状,粗晶区部分铁素体晶粒尺寸达50μm以上;焊接接头在拉伸试验过程中首先在粗晶区产生塑性变形,其不同区域的变形不均匀;屈强比较大的焊接接头母材铁素体晶粒尺寸约为10μm,粗晶区铁素体晶粒尺寸约为20μm;特征区组织细小且马氏体呈岛状弥散分布的焊接接头在拉伸试验过程中能均匀变形。6-mm-thick DP540 dual-phase steel plates having different yield strengths were flash butt welded.The welded joints were tested for microstructure and tensile properties.The results showed that(a)for the welded joint exhibiting yield strength of 338 MPa,the yield-to-tensile strength ratio was 0.62,and the tensile sample ruptured in coarse-grained zone(CGZ)during tensile test;(b)as for the welded joints exhibiting yield strength of about 450 MPa,the yield-to-tensile strength ratios was 0.8 to 0.9,and the tensile sample ruptured in base metal(BM)during the tensile test;(c)the welded joint having less yield-to-tensile strength ratio displayed coarse structure and massive martensite in the BM,and a portion of ferrite grains was as large size as 50μm and more in the CGZ;(d)plastic deformation of the welded joint occurred first in the CGZ during the tensile test,and the deformation in its different zones was nonuniform;(e)as to the welded joint having larger yield-to-tensile strength ratio,the sizes of ferrite grain were about 10μm in BM and about 20μm in CGZ;and(f)the welded joint having fine microstructure and dispersively distributed island-like martensite in the characteristic zones was enabled to deform uniformly during the tensile test.

关 键 词：闪光对焊 DP540 双相钢 屈强比 均匀变形 拉伸性能 

分 类 号：TG457.11[金属学及工艺—焊接]