Traditionally, chemical carriers have their tanks constructed from austenitic stainless steel (316LN). There has been a move towards the use of duplex stainless steel to replace 316LN. An evaluation has been carried out on the basis of cost , corrosion resistance and welding to establish the relative benefits of the two steel types. Techniques involved in this evaluation have been finite element modelling, weld mechanical testing, and transmission electron microscopy. The use of duplex stainless steels has been found to have cost benefits only if the potential reduction in plate thickness of 11% is fully utilised.