TWI Industrial Member Report Summary 96/1979
By J Honeycombe and T G Gooch
A range of stress corrosion resistant stainless steels has been studied, covering duplex ferritic/austenitic and ferritic/martensitic alloys, and an extra low interstitial fully ferritic grade. Butt welds were made in sheet of circa 2mm thickness using the TIG process with filler and susceptibility to intercrystalline attack assessed using acid copper sulphate and potentiostatic test procedures. Hardness, tensile and bend tests were carried out.
The ferritic/austenitic materials showed some HAZ sensitisation, but it is considered that this is unlikely to be of general practical significance. No sensitisation was found with the ferritic/martensitic alloy. Intercrystalline attack was observed in the fully ferritic steel, apparently resulting from surface contamination. From the results obtained, it is concluded that with such materials, surface sensitisation can occur even given good industrial gas shielding practice.
With all alloys, transverse joint tensile strengths were found to be comparable with data supplied by the material manufacturers. Bend test behaviour was generally satisfactory.