Effect of cooling rate on hot-crack susceptibility of duplex stainless steel

The effect of cooling rate on hot-crack behavior of duplex stainless steel (DSS) is investigated using a type ZQS-2000 hot cracking and linear contraction apparatus, in which the hot-crack susceptibility is also evaluated. With the cooling rate decreasing from 6 to 1 °C/s, the ferrite/austenite ratio in DSS decreases from 2.3 to 1.25, while its linear contraction rate increases from 1.59% to 1.9%. The results demonstrate that the cooling rate influences both the ferrite/austenite ratio of DSS and its hot-crack susceptibility. When the cooling rate decreases to 1 °C/s, the hot crack appears firstly on the pitch circle of hot-crack samples. The decreasing cooling rate encourages the hot-crack susceptibility of DSS.