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利用金相法、超高温显微镜及超高压透射电子显微镜技术,对9%Ni 钢焊接熔合区马氏体带的特性,拉应力对9%Ni 钢焊接熔合区组织,性能的影响进行了探讨。试验得出用Cr17Ni13Mn8W3奥氏体钢焊条焊接9%Ni 钢时,熔合区马氏体带中包含具有孪晶精细结构的马氏体,该马氏体带的相变滞后于热影响区的马氏体,其中的残余奥氏体稳定性不高,在拉应力作用或低温条件下易于转变成马氏体,从而增加了熔合区氢致裂纹倾向。提出了9%Ni 钢焊接熔合区氢致裂纹形成的模型。
The effects of martensite band and tensile stress on the microstructure and properties of 9% Ni steel welded zone were investigated by metallographic method, ultra-high temperature microscope and ultra-high pressure transmission electron microscopy. The results show that when martensitic steel is welded with 9% Ni steel by using Cr17Ni13Mn8W3 austenitic steel electrode, the martensitic zone in the fusion zone contains martensite with twins fine structure. The martensitic transformation lags behind that of the heat affected zone The retained austenite is not stable, and easily transforms to martensite under the action of tensile stress or low temperature, thus increasing the tendency of hydrogen induced cracking in the fusion zone. A model of hydrogen induced crack formation in the weld zone of 9% Ni steel was proposed.