Abstract
A study has been made of the effect of welding on the corrosion properties of 18%Cr–2%Mo–titanium stabilisedferritic stainless steel sheetfrom 2 to 3·5 mm thickness and 9 mmplate. Welds were made using the manual metal arc, MIG and TIG processes, with matching, austenitic stainless steel and nickel-based consumables. Intercrystalline, pitting and crevice corrosion resistance of welds was evaluated, using immersion and potentiostatic techniques, with stress corrosion behaviour being assessed using transverse weld tensile samples in MgCl2 and CaCl2 solutions.
Welding promoted some susceptibility to intercrystalline attack, although all welds passed the Strauss bend test criterion for sensitisation. Resistance to pitting and crevice corrosion in FeCl3 was reduced by welding. No stress corrosion was observed in the parent material, but joints made with non-matching composition consumables suffered cracking, although susceptibility was less than that associated with austenitic grades of steel. It is concluded that in most environmental situations, the loss in corrosion resistance as a result of welding will not be significant. For the highest corrosion resistance, the use of matching composition consumables is preferred.
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