This paper discusses the effect of different combinations of preheating and post-heating on the corrosion and hydrogen embrittlement of Grade-91 steel weld joint in the as-welded condition. Though these welds are subjected to post-weld heat treatment (PWHT), there could be long delay in executing this, especially in the case of fabrication of large components, and during this delay, the welds in as-welded conditions are prone to environmental degradations like hydrogen embrittlement and different forms of corrosion. Though recommended minimum preheating and post-heating conditions are already known for welding of this class of steels, marginally increasing the temperature of preheating and post-heating or increasing the duration of post-heating can permit longer delay in the post-weld heat treatment (PWHT), without increasing the risk of environmental degradation. With this objective, a set of thirteen single-V multi-pass gas tungsten arc weld joints of Grade-91 steel fabricated with different preheating and post-heating combinations. Results indicated a significant reduction in residual tensile stresses in the weld metal and reversing into compressive stresses upon preheating and post-heating at 300 °C. Moreover, diffusible hydrogen content and corrosion rate decreased significantly with the preheating and post-heating. However, there are no significant variations in the microstructure, mechanical properties, and hydrogen embrittlement with preheating and post-heating. This study proved that the risk of embrittlement in Grade-91 steel welds due to an indefinite delay in PWHT could be minimized by combined preheating and post-heating.

本文讨论了在焊接条件下，预热和后热的不同组合对91级钢焊接接头腐蚀和氢脆的影响。尽管这些焊缝需要进行焊后热处理（PWHT），但是执行此操作可能会有较长的延迟，尤其是在制造大型零件的情况下，并且在此延迟期间，处于焊接状态的焊缝容易受到环境的影响。氢脆和不同形式的腐蚀等退化。尽管对于此类钢的焊接，已知建议的最低预热和后加热条件已为人所知，但略微提高预热和后加热的温度或增加后加热的持续时间可能会延长焊后热处理的时间（ PWHT），而不增加环境退化的风险。为此目的，用不同的预热和后热组合制造了十三套91级钢的单V多道气体钨极电弧焊接头。结果表明，在300°C的温度下进行预加热和后加热后，焊缝金属中的残余拉应力显着降低，并转变为压应力。此外，随着预热和后热，可扩散氢含量和腐蚀速率显着降低。但是，在预热和后热的情况下，微观结构，机械性能和氢脆没有明显变化。这项研究证明，将PWHT无限期延迟而导致的91级钢焊缝的脆化风险可以通过组合预热和后热来降低。为此目的，用不同的预热和后热组合制造了十三套91级钢的单V多道气体钨极电弧焊接头。结果表明，在300°C的温度下进行预加热和后加热后，焊缝金属中的残余拉应力显着降低，并转变为压应力。此外，随着预热和后热，可扩散氢含量和腐蚀速率显着降低。但是，在预热和后热的情况下，微观结构，机械性能和氢脆没有明显变化。这项研究证明，将PWHT无限期延迟而导致的91级钢焊缝的脆化风险可以通过组合预热和后热来降低。为此目的，用不同的预热和后热组合制造了十三套91级钢的单V多道气体钨极电弧焊接头。结果表明，在300°C的温度下进行预加热和后加热后，焊缝金属中的残余拉应力显着降低，并转变为压应力。此外，随着预热和后热，可扩散氢含量和腐蚀速率显着降低。但是，在预热和后热的情况下，微观结构，机械性能和氢脆没有明显变化。这项研究证明，将PWHT无限期延迟而导致的91级钢焊缝的脆化风险可以通过组合预热和后热来降低。一组13种91级钢的单V多道气体钨极电弧焊接头，采用不同的预热和后热组合制成。结果表明，在300°C的温度下进行预加热和后加热后，焊缝金属中的残余拉应力显着降低，并转变为压应力。此外，随着预热和后热，可扩散氢含量和腐蚀速率显着降低。但是，在预热和后热的情况下，微观结构，机械性能和氢脆没有明显变化。这项研究证明，将PWHT无限期延迟而导致的91级钢焊缝的脆化风险可以通过组合预热和后热来降低。一组13种91级钢的单V多道气体钨极电弧焊接头，采用不同的预热和后热组合制成。结果表明，在300°C的温度下进行预加热和后加热后，焊缝金属中的残余拉应力显着降低，并转变为压应力。此外，随着预热和后热，可扩散氢含量和腐蚀速率显着降低。但是，在预热和后热的情况下，微观结构，机械性能和氢脆没有明显变化。这项研究证明，将PWHT无限期延迟而导致的91级钢焊缝的脆化风险可以通过组合预热和后热来降低。