Abstract
Materials clad with 13% Cr stainless steel have been widely used in refining equipment where high temperature sulfidation is a concern. When such materials are applied in columns, vessels, and heat exchangers, restoration of the cladding using weld overlay is required to bridge over carbon steel or low alloy steel base metal weld seams between the cladding materials during original fabrication or for welding repairs made during service. The first part of this paper describes a comprehensive review of the use of 13-17% Cr stainless steel nearly matching filler metals for restoring the cladding in Japan since the 1960's. The review focuses mainly on how the Japanese industry has improved the weldability of the near matching filler metals and overcome cracking problems in the first layer of the cladding restoration welds. The last half of this paper discusses three possible choices of filler metal for restoring 13% Cr stainless steel cladding: Type 309/309L stainless steel filler metal, Ni-based alloy filler metal, and 13-17% Cr stainless steel nearly matching filler metals. The pros and cons of these filler metals are discussed from the viewpoints of fabrication and corrosion resistance in the service environment.
