What is in fact the upper limit for weld heat input, provided base metal fully passed A-923 criteria?
Because the goal is to limit total time at temperature, it is generally better to complete a weld in fewer passes with relatively high heat input than many passes of lower heat input. The duplex stainless steels can tolerate relatively high heat inputs. It is not impossible to hot crack a duplex stainless steel during welding, but it is rare. The duplex stainless steels have relatively low thermal expansion and high thermal conductivity. The solidification of the duplex filler metals is not prone to hot cracking as is a fully austenitic solidification. Maximum heat input values as high as 65-100 kJ/mm have been found to be satisfactory, depending on the welding process.
Related Questions
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