不同回火工艺对NM500钢板冷弯性能的影响

介绍了河北普阳钢铁有限公司NM500钢板的试制情况。针对NM500钢板试制过程中冷弯性能出现不合的问题,在大生产条件下对890 ℃淬火后的16 mm 厚NM500钢板进行不同回火工艺生产试验,采用显微硬度计、冷弯试验机和金相显微镜对不同回火工艺下NM500钢板力学性能和显微组织进行了检测。结果表明:回火温度200 ℃、在炉时间80 min条件下,16 mm厚NM500钢板组织为正常马氏体组织,内部缺陷得到较好的回复,内应力释放更加完全,因此硬度适中、冷弯性能良好;在回火温度300 ℃、在炉时间80 min条件下,钢板组织中出现回火屈氏体组织,其硬度、冷弯性能下降。

Influence of different tempering processes on the cold bending properties of NM500 plate

The trial production situation of NM500 plate of Hebei Puyang Iron and Steel Co., Ltd. was introduced. Aiming at the problem of unqualified cold bending performance during the trial production of NM500 plate, the 16 mm thickness NM500 plate after quenching at 890 ℃ was subjected to different tempering process tests under mass production conditions, the mechanical properties and microstructure of NM500 plates under different tempering processes were tested using the microhardness tester, the cold bending test machine and the metallurgical microscope. The results show that under the condition of tempering temperature of 200 ℃ and furnace time of 80 minutes, the microstructure of 16 mm thick NM500 plate is normal martensite, internal defects are better recovered, internal stress release is more complete, so the hardness is moderate and the cold bending performance is good. When the tempering temperature is 300 ℃ and the furnace time is 80 min, the tempered troostite microstructure appears in the the plate, and its hardness and cold bending performance is decreased.