奥氏体不锈钢焊缝金属的氢致马氏体相变

Hydrogen Induced Martenslte Transformation In Weld of AusteniticStainless Steels

用X射线衍射的方法 ,研究了充氢以及随后的时效过程中氢致奥氏体不锈钢焊缝金属 (30 8L和 347L)的马氏体相变和晶体结构的变化规律。结果表明 ,充氢能造成奥氏体点阵的膨胀和畸变。氢引起的奥氏体不锈钢焊缝金属的晶格畸变分别为 2 .7%(30 8L)和 2 .9% (347L) ,明显大于奥氏体不锈钢基体所产生的晶格畸变 1.2 % (30 4L)。充氢过程中 ,奥氏体不锈钢焊缝金属能发生ε马氏体相变。并且在随后的时效过程中 ,一部分ε马氏体转变为α′马氏体。即相变的顺序是γ→ε→α′。充氢后以及随后的时效过程中ε +α′马氏体的总量大体保持不变 ,时效 2 4h后 ,ε和α′马氏体的相对含量达到稳定 。

X ray diffraction (XRD) techniques were applied to investigate hydrogen induced martensite and transformation in weld metals of stainless steels during cathodic hydrogen charging and subsequent aging. The results indicate that hydrogen charging can induce austenite lattice expansion in weld metal of stainless steel corresponding to about2.7% (308L) and 2.9% (347L) respectively,greater than about 1.2% (304L) in lattice parameter. The transformation from the fcc γ phase to the hcp ε phase occurred during cathodic charging. During aging,transformation to bcc α phase from the hcp ε phase, however,was incompletd and some ε was restained. Martensite transformation followed the sequence γεα During cathodic hydrogen charging and subsequent aging ,the volume fraction ε+αremained essentially constant. Even if after long time aging, e and a martensite did not disappear.