变形量和加热温度对2205双相不锈钢冲击韧性的影响

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

分析了20 t电弧炉和炉外精炼(EAF+AOD+LF)相结合的冶炼工艺制备的2205双相不锈钢(/%: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)不同热加工加热温度和变形量对其冲击韧性的影响。试验结果表明,在相同加热温度(950、1 050、1 120℃),相同保温时间下(1.5 h),随着变形量的增大(25%、50%、75%),试验钢的晶粒得到较为充分的破碎,但是,过大的变形量造成两相分布不均匀(奥氏体和铁素体),钢中奥氏体含量逐渐降低,其冲击韧性呈现出先增加后减小的趋势;在相同变形量(25%、50%、75%),相同保温时间下(1.5 h),随着加热温度的升高(950、1 050、1 120℃),试验钢的晶粒明显粗化,奥氏体含量降低(57.32%→43.07%),由于奥氏体含量在50%左右时的冲击韧性最佳,其冲击韧性也表现出先增加后减小的规律。当加热温度为1 050℃,保温时间为1.5 h,变形量50%时试验钢的冲击韧性最佳,其室温、-10、-46℃的冲击功分别为299、132、85 J。

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℃,1050℃and 1120℃)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℃,1050℃and 1120℃),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 1050℃,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.