热处理对烧结高铬铸铁耐磨性能的影响

Effects of Heat Treatment on Wear Resistance of Sintered High Chromium Cast Iron

使用粉末冶金技术在1150℃烧结制备了不同致密度的高铬铸铁。对其进行900℃×3 h空冷+100℃×1 h回火的热处理,对经热处理后的高铬铸铁显微组织和耐磨性能进行了研究。结果表明:热处理后的合金致密度增大,因孔隙引起的应力集中减小,结果是冲击韧性与压溃强度增高,耐磨性能变好;热处理后,烧结高铬铸铁获得了马氏体、残余奥氏体和碳化物组织;由于基体脆性增加,冲击韧性和压溃强度降低,但硬度增加导致耐磨性提高。

High chromium cast iron （HCCI） with different relative densities was prepared by powder metallurgy technology at 1150℃. The heat treatment of the HCCI at 900℃ for 3 h, then air cooling and tempering at 100 ℃ for 1 h was carried out. After heat treatment, the microstructure and wear resistance property of the HCCI were studied. The results show that, the relative density increases after heat treatment, and the stress concentration caused by pores decreases, so the impact toughness, crushing strength and wear resistance property become better. Martensite, retained austenite and carbide microstructure of high chromium cast iron are obtained after this heat treatment.The impact toughness and crushing strength decrease because of the increase of matrix brittleness.But the hardness increases to result in the increase of wear resistance property.