Abstract: The tested stainless steel 409L (/% : 0.01C, 0. 82 ~0. 86Si, 0. 26Mn, 0.002 ~0.006S, 0. 034 ~0.041P, 11.44 ~ 11. 51Cr, 0. 24 ~0. 27Ti, 0 ~0. 09Ce) is melted by a 10 kg vacuum induction furnace, forged to 30 mm x 30 mm square billet, cold rolled to 2 mm plate and annealed at 1100 ℃ for 5 min. The effect of Ce on structure annealed at 900℃ for 30 min and on thermal fatigue performance between 900 °C and ambient temperature in steel 409L has been studied. Results show that as the steel contains 0. 03%Ce, the annealed grain of steel 409L is fined and the thermal fatigue performance is best, as the Ce content in steel further increases, the annealed grains coarsen and the thermal fatigue performance of steel gradually decreases. With adding RE element Ce the TiN and TiN-Al₂O₃ compound inclusions basically eliminate and the fined spherical titanium-nitrogen compound inclusions bearing Ce and Al-O-Ti compound inclusions bearing Ce form, and adding excessive Ce, the amount of inclusions at grain boundary increases led to decrease the thermal fatigue performance of steel.

摘要： 试验用409L不锈钢（/%:0.01 C,0.82~0.86Si,0.26Mn,0.002~0.006S,0.034~0.041P,11.44~11.51Cr,0.24~0.27Ti,0~0.09Ce）由10 kg真空感应炉熔炼,锻成30 mm×30 mm方坯,冷轧成2 mm钢板,1100℃ 5min退火。研究了Ce对409L钢900℃ 30min退火组织的影响和900℃-室温热疲劳性能的影响。结果表明,当钢中含0.03%Ce时409L钢退火晶粒细化,热疲劳性能最佳,当进一步增加Ce含量,退火晶粒粗化,钢的热疲劳性能逐渐降低。添加稀土元素Ce后,钢中TiN和TiN-Al₂O₃复合夹杂物基本消除,形成细小球形含Ce的钛氮复合夹杂物和含Ce的Al-O-Ti复合夹杂物,添加过多的Ce,使晶界夹杂物增加,降低热疲劳性能。

关键词: 409L不锈钢, Ce, 退火组织, 热疲劳性能