Test methods and special requirements applied to second generation duplex stainless steels have been evaluated with the goal of simplifying specifications and assuring optimum quality material. The tests evaluated included tensile, bend, hardness, impact toughness, phase balance, metallographic, magnetic, and corrosion tests. Emphasis was placed on tests most appropriate for detection of detrimental intermetallic phases in mill products and welds, not on fitness-for-service tests. This evaluation has led to the following conclusions:

– Narrow, standard specification composition ranges for chromium, molybdenum and nitrogen are especially beneficial.

– Metallographic evaluation should be required for the qualification of mill products and welding procedures, but it requires superior metallographic technique. Because it may be open to subjective interpretation, metallography should be used for acceptance but not rejection. It should be used in addition to either impact testing or corrosion testing to qualify duplex stainless steel mill products.

– Impact testing is useful if the test temperature and acceptance criteria are meaningfully related to the grade and condition being evaluated.

– Corrosion testing, in accordance with ASTM A 923 Method C, is one of the most cost effective methods of testing provided that the test temperature is meaningful for the detection of detrimental conditions, and the absence of edge corrosion is included in the acceptance criteria. Corrosion testing has low sensitivity to sample selection and preparation.