高强度螺栓中δ铁素体影响的研究与探讨

Study on the influence of delta ferrite in high-strength bolts

用于制造高强度螺栓的材料,在调质热处理过程中,表面的磷元素会向内扩散,在金相中呈现δ相,会使得螺栓表层异常硬化,导致螺栓整体机械性能降低。特别将导致材料对脆性敏感度提升、耐疲劳强度降低,组装后螺栓延迟断裂后果,有车辆召回的风险。文章通过对δ铁素体在高强度螺栓中产生的原因进行论述,重点说明δ铁素体对零件质量的影响,并提出了解决该问题的若干技术途径。

Material used to make high-strength bolts,in the tempering heat treatment process,the surface of the phosphorus element will diffuse,in the metallographic phase,will make the bolt surface abnormal hardening,leading to the overall mechanical properties of bolts.In particular,it will increase the sensitivity of materials to brittleness,reduce fatigue resistance,delay fracture of bolts after assembly,and risk of vehicle recall.This paper is to discuss the reason of the ferrite in the high-strength bolt,the key to explain the influence of ferrite on the quality of parts,and to propose some technical approaches to solve the problem.