锻造斗齿的热处理工艺及组织性能

Heat treatment process of forged bucket tooth and its microstructure and properties

以锻造斗齿成品及斗齿用30CrMnSi钢亚温淬火工艺为研究对象,对斗齿成品不同部位的洛氏硬度及显微组织进行了分析;对30CrMnSi钢经不同模拟锻造余热淬火工艺处理后的组织和性能进行了对比研究。结果表明:斗齿成品表面硬度略低于次表层2~3 HRC,齿尖硬度高于齿根硬度5~10 HRC。通过模拟锻造余热分段淬火工艺,30CrMnSi钢在870℃水淬时,其冲击韧性最高,为74 J;当淬火温度低于870℃时,由于奥氏体化不均匀或较多铁素体的出现会导致冲击韧性降低;当淬火温度高于870℃时,由于加热时奥氏体晶粒粗大,淬火后所得马氏体也粗大,冲击韧性降低。建议生产中采用斗齿齿尖、齿根同时入水的整体淬火工艺,以使斗齿整体获得较高的硬度和韧性。

The Rockwell hardness and microstructure of different locations of 30CrMnSi steel bucket teeth forged and intercritical quenched were analyzed,respectively. The microstructure and properties of 30CrMnSi steel treated by different simulated forging residual heat quenching process were compared. The results show that the surface hardness of the bucket tooth is slightly lower than the subsurface by 2-3 HRC,tooth tip hardness is higher than the root by 5-10 HRC. By simulating forging residual heat subsection quenching,the impact toughness of 30CrMnSi steel is the highest when quenched at 870 ℃,which is 74 J. When the quenching temperature is below 870 ℃,the impact toughness will decrease due to inhomogeneous austenitization or the appearance of more ferrite;When the quenching temperature is higher than 870 ℃,due to the austenite grain coarsening during heating,the martensite obtained after quenching is also coarse,and the impact toughness decreases. It is suggested that the integral quenching process of the tooth tip and tooth root entering water at the same time should be adopted,in order to obtain higher hardness and toughness for the whole bucket tooth.