Corrosion resistance, structure and properties of austenitic tig weld joints

The aim of the research was to examine corrosion resistance, structure and properties of 50.8 mm diameter and 1.8 mm thick austenitic steel X5CrNi8-10 (1.4301) tubes weld joints. The welding process was carried out using manual and automatic Tungsten Inert Gas (TIG) welding process without additional material. The scope of the research included microscopic observations of welds cross-sections, hardness tests on welds cross-sections, bending and static tensile tests, salt spray corrosion tests. The samples tested in the salt chamber were then investigated by macroscopic observations, surface morphology evaluation and chemical composition analysis of micro areas. The non-destructive and destructive tests of weld joints revealed higher quality and properties of automatically welded joints. The salt spray corrosion tests allowed to determine the type and degree of destruction of the material surface. Numerous oxidized areas with lower chromium and nickel content, chloride precipitation and pitting were observed on the surface of TIG manually welded samples. No significant corrosion products were observed on the surfaces of TIG automatically welded samples.