| 摘要 |
PURPOSE:To increase cleavage crack resistance of reaction vessels in hydrogen environment of high temperature and high pressure, by build up welding austenitic stainless steel containing delta ferrite phase on base metal of carbon steel or low alloy steel and then performing surface layer build up welding of stainless steel etc. CONSTITUTION:When build up welding stainless steel or Ni alloy steel etc. on base metal of carbon steel or low alloy steel, preceding build up welding of a welded metallic layer having composition of austenitic stainless steel of following composition is performed as an intermediate layer. That is, the steel contains >=2.0% delta ferrite phase in which ratio of Cr equivalent expressed by (%Cr)+(%Mo)+1.5(%Si)+0.5(%Nb) to Ni equivalent expressed by (%Ni)+ 30(%C)+0.5(%Mn). Then, surface layer building up is performed on the preceding built up layer. This build up welding provides effective lining for surface layer of base metal of carbon steel or low alloy metal of chemical reaction containers used for handling of high temperature and high pressure hydrogen.
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