Study on the optimum hot forming temperature and solution heat treatment temperature for the super duplex stainless steel weld

수퍼 이상 스테인리스강 용접부의 최적 열간 성형온도 및 용체화 열처리 온도에 관한 연구

In order to establish the optimum hot forming temperature and solution heat treatment temperature for 25% chromium super duplex stainless steel weld, a commercial 25%Cr-10%Ni-4%Mo weld metal for super duplex stainless steel(UNS S32750) with different solution heat treatment conditions at $1100^{\circ}C,\;1050^{\circ}C,\;1025^{\circ}C\;and\;1000^{\circ}C$ for 1.5 hours has been investigated by means of optical metallography, and estimated mechanical properties. It is found that exposure to elevated temperatures at $1050^{\circ}C,\;1025^{\circ}C\;and\;1000^{\circ}C$ except $1100^{\circ}C$ brings partial decomposition of ferrite to austenite and sigma phase, which deteriorates their properties and heat treatment at $1100^{\circ}C$ shows acceptable mechanical properties.