高合金管穿孔顶头的性能与失效形式研究

Study on properties and failure modes for piercing plug of high alloy steel

顶头是斜轧穿孔的核心工具,其寿命长短对穿孔毛管质量和成本均有重要影响。采用金相显微镜、扫描电镜、Gleeble热模拟、摩擦磨损仪等手段,研究顶头显微组织、硬度、变形抗力和摩擦磨损性能,梳理总结高合金管穿孔顶头的典型失效形式。研究结果表明,顶头的显微组织为索氏体,维氏硬度(HV)约258,摩擦因数约0.45。在900~1250℃范围,随着温度的升高,顶头的变形抗力从290 MPa降低到77 MPa。高合金管穿孔顶头典型失效主要有塌鼻、戴帽、掉肉、黏钢、纵裂等几种形式,失效原因为穿孔顶头在激冷激热轧制环境下,受到了极大的轴向力、压应力、切应力。

Plug is the key tool for cross-piercing,its lifespan has a significant impact on the quality and cost of the hollow bloom.The methods of etallographic microscope,scanning electron microscope,Gleeble thermal simulation,and friction and wear tester were used to study the microstructure,hardness,deformation resistance,and friction and wear performance,and the typical failure modes of piercing plugs of high alloy tube were summarized.Research results show that the micro-structure of the plug is sorbite,the Vickers hardness(HV)is approximate 258,the friction and friction factor is approximate 0.45.Within the range of 900~1250℃,as the temperature increases,the deformation resistance of the plug decreases from 290 to 77 MPa.The typical failure modes of plugs used for high alloy tube piercing include nose collapse,wearing a hat,loss of flesh,sticking,and longitudinal cracks.The causes of failure mode are that the plug is subjected to great axial force,compressive stress and shear stress in the environment of quenching and hot rolling.