The Influence of Deformation and Heating Temperature on the Impact Toughness of 2205 Duplex Stainless Steel

The 2205 duplex stainless steel （/%：0.03C， 1.00Si， 2.00Mn， 0.03P， 0.02S， 21.00-23.00Cr， 4.50-6.50Ni， 2.50-3.50Mo， 0.08-0.20N） were prepared by a smelting process combining 20 t electric arc furnace and ladle refining （EAF+AOD+LF）. Then 2205 duplex stainless steel was hot processed. In this paper， the influence of impact toughness of 2205 duplex stainless steel at different heating temperatures and deformation was studied in hot working process. The test results showed that： At the same heating temperature （950 ℃， 1 050 ℃ and 1 120 ℃） and holding time （1.5 h）， with the increase of deformation （25%， 50% and 75%）， the grain of test steel was broken more fully， but the excessive deformation of test steel caused uneven distribution of two phases（austenite and ferrite）， and the austenite content of steel gradually decreased， the impact toughness showed a trend of increasing first and then decreasing； Under the same deformation amount （25%， 50% and 75%） and the same holding time （1.5 h）， with the increase of heating temperature （950 ℃， 1 050 ℃ and 1 120 ℃）， the grains size of test steel were obviously coarsened， the austenite content of steel decreased （57.32%→43.07%）， because the impact thermal property was best when the austenite content was about 50%，therefore， the impact toughness of steel also showed the law of first increasing and then decreasing. When the heating temperature was 1 050 ℃， the holding time was 1.5 h and the deformation amount was 50%， the impact toughness of test steel was the best， The impact energy of test steel were 299 J ， 132 J ，85 J at room temperature， -10 ℃ and -46 ℃， respectively.