MARTENSITE STAINLESS STEEL WELDED STEEL PIPE

摘要

This invention relates to a large-diameter, thick-wall martensitic stainless steel welded pipe. For this welded pipe, the size of the raised weld bead portion on the inside surface is restricted to be small based on a conditional formula derived by considering the bead width and height and the yield strength of the base metal and of the weld metal. As a result, the base metal portion and pipe inside surface seam portion of this welded pipe are superior in corrosion resistance, in particular stress corrosion cracking resistance (SCC resistance). The sulfide stress corrosion resistance (sour gas resistance) and carbon dioxide corrosion resistance can be further improved by selecting the chemical compositions. This welded pipe is very well suited for use as a pipe for a pipeline for conveying a crude oil and a natural gas with no dehydration treatment, which is highly corrosive to metals.