窄淬透性齿轮钢17CrNiMo6工艺实践

Process Practice on Gear Steel 17CrNiMo6 with Narrow Hardenability

针对齿轮钢17CrNiMo6窄淬透性带、高纯净、细晶粒、高强韧等生产控制难点,通过优化成分,采用30 t EAF-LF-VD冶炼流程,经吹氩搅拌、白渣还原、真空精炼、氩气保护,控制脱氧、除杂、合金元素加入、浇注温度、速度、钢液冷却等工艺,主控成分C、Mn、Cr、Mo、Ni达到内控要求,气体和非金属夹杂得到有效控制,S≤0.003%、P≤0.005%、[O]≤0.001 6%、[N]≤0.007 5%、[H]≤0.000 13%;淬透性带宽控制在1~3 HRC,硬度值达到客户要求,低倍组织未发现点状偏析和肉眼可见的缺陷。锻造热处理后产品组织均匀,本质晶粒度达到8级,混晶不超过10%;强度、硬度值满足要求,室温和-40℃的低温韧性较好,强韧性达到良好匹配。

To cope with the production control difficulties of gear steel 17CrNiMo6 such as narrow hardenability range,high purity,fine grain and high strength and toughness,chemical composition was optimized,30 t EAF-LF-VD smelting route was adopted with argon stirring,white slag reduction,vacuum refining and argon protection,and process parameters of deoxidation,impurity removal,alloying element addition,casting temperature and speed and cooling were better controlled.With these measures,main elements like C,Mn,Cr,Mo and Ni reach inner target,gas and non-metallic inclusions are effectively controlled that S≤0.003%,P≤0.005%,[O]≤0.0016%,[N]≤0.0075% and[H]≤0.000 13%.Hardenability is controlled to be within1-3HRC and the hardness meets customers’ requirement.No dot-like phase or visually inspected defect is found for macro-structure.And after forging heat treatment,the product structure gets uniform,inherent gain size reaches level 8 and mixed crystal is no more than 10%.The strength and hardness value meet the requirement,the toughness is good at room temperature and-40 ℃,and the strength and toughness match well.