Abstract: Linear expansion coefficient, differential scanning calorimetric (DSC) and heat capacity at constant pressure (Cp) curves, and high temperature mechanical properties of austenite stainless steel 304 (/%: 0. 040C, 0. 45Si, 1. 18Mn, 0. 030P, 0. 003 S, 17. 24 Cr, 8. 11 Ni) 40 mm x 1 500 mm hot-rolled plate are tested and analyzed by using Gleeble-1500D thermal simulation testing machine, DIL402C thermal dilatometer and STA449F3 comprehensive thermal analyzer. Results show that 1-est brittleness zone of steel 304 is 1 300 T to melting point, 3-rd brittleness zone is 950 ~ 1 050 °C, the reduction of area at 1 050 ~ 1 250 °C is ≥60%, it has better hot ductility; the linear expansion and contraction coefficient of steel are respectively 20. 97 x 10^-6 〜21. 56 x 10^-6 and 21. 25 x 10^-6~ 21. 84 x 10^-6, so it belongs to crack sensitive steel grade; during heating process from 1 000 °C to 1 400 °C the fluctuation of Cp curve is larger, it indicates there is crystallographic transformation to easily form defects in steel ； during cooling of steel 304 from 1 450 °C to 1 200 °C the curve of DSC is unsmooth, it indicates there is phase transformation in steel easily to produce cracks in steel.

摘要： 采用Gleeble-1500D热模拟机、DILA02C热膨胀仪和STA449F3综合热分析仪,测试分析了304不锈钢(/%:0.040C,0.45Si,1.18Mn,0.030P,0.003S,17.24Cr,8.11Ni)40 mm×1 500 mm热轧板的线膨胀系数、差热(DSC)及定压热容(Cp)曲线和高温力学性能。结果表明,304不锈钢的第I脆性区为1 300℃到熔点,第Ⅲ脆性区为950~1 050℃,在1 050~1 250℃C,断面收缩率≥60%,塑性较好。钢的膨胀及收缩系数分别为20.97×10^-6~21.56×10^-6与21.25×10^-6~21.84×10^-6,属裂纹敏感性钢种。1 000~1 400℃升温过程中,Cp曲线波动大,存在晶型转变,易产生缺陷。304钢在1 450~1 200℃降温过程中,DSC曲线不平滑,有相变发生,易产生裂纹。