大厚度钢板焊接接头显微组织及断裂韧性研究  

Study on Microstructure and Fracture Toughness of Welded Joint of Large Thickness Steel Plate

作　　者：石红昌 黄安明 SHI Hongchang;HUANG Anming

机构地区：[1]德阳天元重工股份有限公司,四川德阳618000

出　　处：《大型铸锻件》2024年第2期44-48,63,共6页Heavy Casting and Forging

摘　　要：使用宏观低倍体式显微镜和微观金相显微镜观察ZG370-580H+Q460ND大厚度钢板焊接接头,分析了焊接缺陷和显微组织组成及形成机制。通过对焊接接头母材(BM)、热影响区(HAZ)和焊缝(WZ)进行硬度值测量和裂纹尖端张开位移(CTOD)试验,研究了焊接接头的力学性能。结果表明:焊接接头成型情况良好,未发现明显的焊接缺陷;接头两侧热影响区的维氏硬度高于焊缝和母材,其中Q460ND侧热影响区最高。两侧HAZ的组织组成相同,过热区主要由板条状铁素体(LF)针状铁素体(AF)和少量珠光体(P)组成,正火区主要由均匀分布的细小珠光体(P)和铁素体(F)组成;WZ存在等轴晶区和柱状晶区,这是由多层多道焊的焊接工艺决定的。焊接接头CTOD值最大为0.7621 mm,最小为0.3037 mm,接头不同位置CTOD平均值从大到小排序为:焊缝>ZG370-580H侧热影响区>Q460ND侧热影响区,试验的所有试样CTOD值均大于相关标准所规定的最小值。The welded joints of ZG370-580H+Q460ND large-thickness steel plates were observed with macroscopic low-power microscope and microscopic metallographic microscope,and the defects after welding,microstructure,and formation mechanism were analyzed.The mechanical properties of the welded joint were studied after hardness measurement and crack tip opening displacement(CTOD)test on the base metal(BM),heat affected zone(HAZ),and welds(WZ).The results show that the welded joint is in good shape and no obvious defects due to welding are found.The Vickers hardness of the heat-affected zone on both sides of the joint is higher than that of the weld and the base metal,and the hardness of the heat-affected zone on the Q460ND side is the highest.The microstructure of HAZ on both sides is the same.The superheated zone is mainly composed of lath ferrite(LF),acicular ferrite(AF),and a small amount of pearlite(P).The normalized zone is mainly composed of evenly distributed fine pearlite(P)and ferrite(F).The equiaxed crystal zone and columnar crystal zone do exist in WZ,which is determined by the welding procedure of multi-layer and multi-pass welding.The maximum CTOD value of the welded joint was 0.7621mm,and the minimum CTOD value was 0.3037mm.The average CTOD values of different positions of the joint sort from largest to smallest as weld>ZG370-580H side heat affected zone>Q460ND side heat affected zone.The CTOD values of all specimens tested were higher than the minimum values specified in relevant standards.

关 键 词：ZG370-580H+Q460ND 焊接接头 力学性能 CTOD 

分 类 号：TG44[金属学及工艺—焊接]