一种采棉机采棉头花键轴断裂失效分析

A kind of failure analysis of the spline shaft fracture in a cotton picker head

针对采棉机采棉头的花键轴装机后累计工作近200 h,采收233 hm2棉花后发生断裂的问题,通过对花键轴进行断口形貌观察、有限元分析、化学成分分析、高倍金相检验、拉伸力学性能试验以及显微硬度测定,对花键轴断裂原因进行了探究。结果表明花键轴断裂失效的根本原因是热处理工艺不足,导致材料强度不达标,当花键轴承受超出其设计负荷的扭矩时局部应力超过了基材的承载能力,最终发生扭转断裂,并针对材料强度问题提出减少花键轴断裂的方案。

In response to the problem of fracture occurring in the spline shaft of a certain model cotton picker head after nearly 200hours of cumulative operation and harvesting of over 3500 acres of cotton,a series of investigations into the causes of the spline shaft fracture was conducted.The investigations involved fracture surface observation,finite element analysis,chemical composition analysis,high-magnification metallographic examination,tensile mechanical property testing,and microhardness testing of the spline shaft.The results show that the fundamental cause of the fracture was insufficient heat treatment,leading to inadequate material strength.When the spline shaft was subjected to torque exceeding its design load,the local stress on the shaft exceeded the material's load-bearing capacity,resulting in torsional fracture,and a scheme to reduce the fracture of the splined shaft was proposed for the material strength problem.