摘要
The mechanical properties and microstructure features of the fine-grained heat-affected zone(FGHAZ) of ASTM4130 steel was investigated by optical microscope(OM),scanning electron microscope(SEM),transmission electron microscope(TEM),and welding thermal simulation test.It is found that serious embrittlement occurs in the FGHAZ with an 81.37% decrease of toughness,compared with that of the base metal.Microstructure analysis reveals that the FGHAZ is mainly composed of acicular,equiaxed ferrite,granular ferrite,martensite,and martensite-austenite(M-A) constituent.The FGHAZ embrittlement is mainly induced by granular ferrite because of carbides located at its boundaries and sub-boundaries.Meanwhile,the existence of martensite and M-A constituent,which distribute in a discontinuous network,is also detrimental to the mechanical properties.
The mechanical properties and microstructure features of the fine-grained heat-affected zone(FGHAZ) of ASTM4130 steel was investigated by optical microscope(OM),scanning electron microscope(SEM),transmission electron microscope(TEM),and welding thermal simulation test.It is found that serious embrittlement occurs in the FGHAZ with an 81.37% decrease of toughness,compared with that of the base metal.Microstructure analysis reveals that the FGHAZ is mainly composed of acicular,equiaxed ferrite,granular ferrite,martensite,and martensite-austenite(M-A) constituent.The FGHAZ embrittlement is mainly induced by granular ferrite because of carbides located at its boundaries and sub-boundaries.Meanwhile,the existence of martensite and M-A constituent,which distribute in a discontinuous network,is also detrimental to the mechanical properties.
基金
supported by the National High-Tech Research and Development Program of China (No.2006AA09A103-6)