Paper on how welding influences material properties and must be considered in terms of design and initial fabrication and any subsequent repair during the life of a vessel. Additionally, new fabrication processes are being developed such as laser and laser hybrid welding, friction stir welding of aluminium alloys and improved wet underwater repair, necessitating understanding of the corrosion performance of such new weldments which may be used in the marine shipping industry.
The issues influencing the corrosion performance of welded carbon and low alloy steels, corrosion resistant alloys and aluminium alloys are presented. Possible issues related to wet underwater repair welds for permanent solutions are highlighted. Coating of weldments can be more difficult than parent material due to the weld profile and accessibility, whilst fatigue at welds may cause coating failure. Future applications of improved coatings based on thermally sprayed aluminium to protect carbon steels and corrosion resistant alloys in the marine environment is discussed. Recommendations of areas for further assessment in terms of long term corrosion performance of welds and corrosion fatigue in sour oil storage tanks are provided.