基于45钢基体焊后不同回火温度对熔合区组织及韧性的影响

Study on Effect of Postweld Tempering Temperature on Microstructure and Toughness of 45 Steel Surfacing Welding Fusion Zone

利用高合金药芯焊丝对45钢基体进行堆焊,焊后分别对堆焊试样进行100、200、300、400℃回火处理。采用金相显微镜以及扫描电镜对焊后不同回火温度条件下的熔合区组织及冲击断口形貌进行了对比分析。结果表明:焊后不同回火温度条件下熔合区组织及熔覆层断口形貌差异较大,随着回火温度提高,热影响区粗大的魏氏组织逐渐减少,粒状铁素体及珠光体逐渐增多,同时熔覆层断面韧性逐渐升高,并逐渐出现大量较小较深的韧窝,韧性发生明显改善,当回火温度达到400℃时,热影响区魏氏组织完全转变为大小相对均匀的粒状铁素体及珠光体,熔覆层断面的韧窝较深、较小且数量较多。

Taking high alloy flux-cored wire on 45 steel for surfacing welding, the welding samples were tempered at 100℃, 200 ℃, 300℃, 400℃, respectively after welding. The microstructure and toughness of the samples under different tempering temperature conditions were compared by means of microscope, and SEM. The results show that the microstructure and fracture morphology of the fusion zone generate obvious differences under different postweld tempering temperature conditions. With the increase ofpostweld tempering temperature, the rough widmanstatten of HAZ reduces gradually, and the granular ferrite and pearlite increase gradually. At the same time, the impact fracture toughness of the cladding layer increases with the increase of postweld tempering temperature, and a large number of small and deep nests appear, and the toughness improves significantly. When the postweld tempering temperature reaches 400 ℃, the widmanstatten structure of heat affected zone changes into relatively uniform size granular ferrite and pearlite completely, and the toughening nest of the cladding layer is deeper and larger.