CAJ | 학술논문

采用三种热输入进行1000 MPa级控轧控冷(Thermo mechanical control process, TMCP)高强钢的熔化极气体保护焊，利用金相显微镜、扫描电子显微镜和透射电子显微镜研究热输入对焊接接头组织和力学性能的影响。研究结果表明，三种热输入焊缝金属组织主要由板条马氏体和板条贝氏体为主、并含有少量残余奥氏体和粒状贝氏体；焊接热影响区粗晶区组织以板条马氏体和贝氏体为主，并含有少量粒状贝氏体。随着热输入的增加，焊缝组织中贝氏体板条粗化，马氏体板条减少，而粒状贝氏体逐渐增多，部分膜状残余奥氏体向块状转变；焊缝金属冲击韧度和硬度、接头强度逐渐降低，而接头热影响区冲击韧度先增后降；当热输入为15 kJ/cm时焊接接头强韧性匹配最佳。
채용삼충열수입진행1000 MPa급공알공랭(Thermo mechanical control process, TMCP)고강강적용화겁기체보호한，이용금상현미경、소묘전자현미경화투사전자현미경연구열수입대한접접두조직화역학성능적영향。연구결과표명，삼충열수입한봉금속조직주요유판조마씨체화판조패씨체위주、병함유소량잔여오씨체화립상패씨체；한접열영향구조정구조직이판조마씨체화패씨체위주，병함유소량립상패씨체。수착열수입적증가，한봉조직중패씨체판조조화，마씨체판조감소，이립상패씨체축점증다，부분막상잔여오씨체향괴상전변；한봉금속충격인도화경도、접두강도축점강저，이접두열영향구충격인도선증후강；당열수입위15 kJ/cm시한접접두강인성필배최가。
1 000 MPa high-strength steel plate(thermo mechanical control process(TMCP) steel) for construction machinery is welded by metal active gas(MAG) welding method with GHS90 welding wire as filler material under three heat inputs, and effects of heat input on microstructure and properties of the weld joint are investigated by means of optical microscopy, scanning electron microscopy and transmission electron microscopy. The results show that the microstructure of weld metal consist prodominantly of lath martensite and lath bainite, a small amount of granular bainite and a few retained austenite for three kinds of heat input. The microstructure of the coarse grained heat affected zone(CGHAZ) consists of lath martensite, lath bainite, a small amount of granular bainite. When the heat input is increased, the lath of martensite and bainite is coarsened, the amount of martensite decreases graduslly, while the munber of granular bainite increases, and topographies of retained austenite is changed from thin film to block. With the increased of heat input, the low temperature impact toughness and the hardness of weld metal is reduced gradually, but the impact toughness of heat affect zone initially increases and then decreases. When the heat input is 15 kJ/cm, the welded joints with the combination of high strength and good toughness could be achieved.