超高强度钢制螺栓的短时回火工艺

Short-time tempering process for ultra-high strength steel bolts

讨论采用感应加热的方式对30CrMnSiNi2A钢制螺栓试验件进行局部短时回火处理,分别在700、600和550℃温度下对试样进行保温,保温时间为10 s至50 s,研究了温度和保温时间对试样不同区域硬度的影响,并确定了感应加热的最佳工艺。采用最佳工艺处理了30CrMnSiNi2A钢力学性能试样,测试了其偏斜拉伸和低周疲劳性能,并与铅浴回火工艺进行了比较。研究表明感应加热600℃保温10 s的工艺稳定性最佳,三区硬度分别为:回火区域67~68 HRA;过渡区70~72 HRA;非回火区74~75 HRA,可满足典型制件的技术要求,其处理的偏斜拉伸性能和低周疲劳性能与铅浴工艺处理相当。感应工艺可取代传统有毒的铅浴工艺,用于30CrMnSiNi2A钢制螺栓的生产。

Local short-time tempering process on the samples of 30CrMnSiNi2 A ultra-high strength steel bolt were disscussed by using induction heating,the samples were heated at 700,600 ℃ and 550 ℃,and the holding time was from 10 s to 50 s,effects of the temperature and holding time on the hardness of different zones were investigated,and the optimum process of induction heating was determined. The optimum process was used to 30CrMnSiNi2 A samples and the mechanical properties,the deflection tensile property and low cycle fatigue properties were tested,which were compared with lead bath tempering process. The results show that the induction heating at600 ℃ for 10 s gets the best process stability,the hardness of three zones are: tempering region from 67 to 68 HRA; transitional region from70 to 72 HRA and non tempering region from 74 to 75 HRA,which can satisfy the requirements of typical parts,the deflection tensile property and low cycle fatigue properties got the same results as the samples treated with lead bath local tempering. The induction heating process can apply to production practice of 30CrMnSiNi2 A bolts,and replace the traditional toxic lead bath process.