超高强钢延迟裂纹的研究

STUDY ON THE DELAYED CRACKING OF ULTRA HIGH STRENGTH STEEL

摘要:

采用四点弯曲试验及表面裂纹法试验分别研究了37SiMncrMoV 钢焊接接头的氢致裂纹和应力腐蚀开裂。高湿度能增大氢致裂纹和应力腐蚀开裂倾向。扫描电镜显示了氢致裂纹断口的沿晶断裂特征。用扫描电镜及光学显微镜研究了热影响区的局部熔化区及淬火区显微组织对裂纹倾向的影响。采用改进的焊接工艺,防止了高压容器的低应力破坏。

Abstract:

The hydrogen induced cracking and the stress corrosion cracking in weld joints of 37 SiMnCrMoV steel are investigated by means of four-point bending test and surface crack test,respectively.High environment humidity increases the susceptibility to hydrogen induced cracking and stress corrosion cracking.Scanning electron microscope fractography shows the intergranular character of hydrogen induced cracking.The effect of microstructure of HAZ(partially melted zone and quenched zone) on cracking susceptibility is studied by scanning electron microscope and optical microscope.Welding procedures are adjusted to prevent brittle failure of high pressure vessel.