14NiCrMo10 6V与Q345E钢过渡匹配焊接接头的组织与力学性能

采用E551T1-Ni2药芯焊丝对Q345E钢与14NiCrMo10 6V钢进行焊接,并通过室温拉伸、弯曲、冲击、硬度试验以及金相分析等对焊接接头的力学性能与显微组织进行了研究。结果表明:采用此焊丝可以获得拉伸、弯曲和冲击性能均良好的焊接接头,焊缝硬度在200～250HV之间;焊缝处晶界组织为先共析铁素体、少量无碳贝氏体(从晶界伸向晶内),晶内为针状铁素体与珠光体,个别部位有粒状贝氏体;Q345E钢侧热影响区与焊缝过渡区的组织为沿晶界析出的块状先共析铁素体和向晶内生长的条状铁素体以及少量的珠光体和贝氏体;14NiCrMo10 6V钢侧热影响区与焊缝过渡区的组织为板条状马氏体。

Microstructure and Mechanical Properties of Transition Matched Welded Joints of 14NiCrMo10 6V and Q345E Steel

E551T1-Ni2 flux cored wire was used to weld the steels between Q345E and 14NiCrMo10 6V,and then the mechanical properties and microstructure of the welded joints were studied through room temperature tensile,bending,impact and hardness tests as well as metallography analysis.The results show that welded joints with good tensile property,bending property and impact toughness could be obtained using the flux cored wire;the hardness of the weld seam was in the range of 200-250 HV.The microstructure at the grain boundaries in the weld seam was pre-eutectoid ferrite,a little carbon-free bainite which stretched from grain boundaries into the grains,and acicular ferrite and pearlite in the grains,also some granular bainite distributed at individual locations.The microstructure of heat affected zone(HAZ) and weld seam transition area at the side of Q345E steel consisted mainly of block pre-eutectoid ferrite which precipitated along the grain boundaries,and some lath ferrite which stretched into the grains,and small amount pearlite and bainite.While the microstructure of HAZ and weld seam transition area at the side of 14NiCrMo10 6V steel was lath martensite and granular bainite..