Welding of martensitic creep-resistant steels

The majority of equipment and pipelines working at high temperatures in fossil-fueled power stations are made of creep-resistant steel with 9 to 12% chromium. For joining this type of steel, martensitic welding is undertaken, which is carried out following preheating to a temperature lower than the M-s. The preheat temperature is usually determined by experiments or following normal industrial practice. In spite of this, some materials are markedly crack sensitive, and moreover, cracks form in the welded joints. The authors have carried out detailed investigations to explore the reason for this phenomenon and have constructed a method to reduce such failures. The principal goal of this research was to provide a solution for welding of high-chromium, martensitic, creep-resistant steel with repeatable high quality.