CAJ | 학술논문

按照低匹配设计原则，采用熔化极气体保护焊对屈服强度为700 MPa级的低合金高强钢进行了焊接。采用光学显微镜、扫描电镜和力学性能试验研究了焊接接头的组织和性能。结果表明，焊缝区组织主要为针状铁素体和少量先共析铁素体，粗晶热影响区组织为上贝氏体；焊缝区显微硬度明显低于母材，焊缝区-40℃时的冲击韧度（AKV）为58 J，抗拉强度达到了母材抗拉强度的92．4％，焊接接头的综合力学性能良好。
안조저필배설계원칙，채용용화겁기체보호한대굴복강도위700 MPa급적저합금고강강진행료한접。채용광학현미경、소묘전경화역학성능시험연구료한접접두적조직화성능。결과표명，한봉구조직주요위침상철소체화소량선공석철소체，조정열영향구조직위상패씨체；한봉구현미경도명현저우모재，한봉구-40℃시적충격인도（AKV）위58 J，항랍강도체도료모재항랍강도적92．4％，한접접두적종합역학성능량호。
700 MPa grade high strength low alloy steel was welded by gas metal arc welding ( GMAW) process on the principle of a undermatching design .The microstructure and properties of the welded joint were investigated by OM, SEM and mechanical property tests .The results show that the microstructure of the weld zone consists mainly of acicular ferrite and a small amount of proeutectoid ferrite , the microstructure of coarse grain heat affected zone is upper bainite , and that the microhardness of the weld zone is significantly lower than that of the base metal , the impact toughness ( AKV ) of the weld zone is 58 J at -40 ℃, and the tensile strength of welded joint is as high as 92.4%of that of the base metal , the welded joint providing good comprehensive mechanical properties .