Scholarlink

<p>A premature failure occurred in the head pulley shaft of the steep-inclined conveyor system used for coal handling at COREX Plant, JSW Steel Vijayanagar Ltd. where the component experienced a rotating-bending fatigue fracture near a geometric transition region. Metallurgical and mechanical characterization confirmed that the shaft was not manufactured from the specified quenched-and-tempered EN19 (42CrMo4) chromium–molybdenum steel. Instead, the component was produced from a low-alloy plain carbon steel in an untreated ferrite–pearlite condition, possessing substantially lower strength and fatigue resistance than required for service. Chemical composition analysis showed markedly reduced alloying content, with chromium and molybdenum measuring only 0.13% and 0.002%, respectively—far below the EN19 requirements of 0.90–1.40% Cr and 0.20–0.40% Mo. Hardness measurements ranged from 180 to 203 BHN, corresponding to an annealed/as-rolled condition, and well below the 280–320 BHN expected for a properly quenched-and-tempered EN19 shaft. Microstructural evaluation confirmed a ferrite–pearlite morphology with no evidence of tempered martensite, while inclusion analysis (ASTM E45) indicated elevated alumina and globular oxide inclusions (up to <i>B</i> = 1.0 and <i>D</i> = 1.5 ratings). Fractographic examination identified multiple ratchet marks and fatigue striations originating at the shaft surface, consistent with high-cycle fatigue under cyclic bending stresses. The combined effects of incorrect material grade, absence of heat treatment, and poor steel cleanliness significantly reduced fatigue resistance, ultimately leading to shaft failure. Recommendations include mandatory verification of material certification, quench-and-temper processing, steel cleanliness specifications, and alignment checks to enhance shaft reliability in future installations.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Failure Analysis of Head Pulley Shaft in a Steep-Inclined Coal Conveyor System

  • 期刊论文

  • 发表日期：

    2026年3月28日

查看全文
  • J. N. Mohapatra,
  • Dhanraj Patil,
  • Ravindra D. Kulkarni,
  • Satish Kumar Dabbiru

摘要

A premature failure occurred in the head pulley shaft of the steep-inclined conveyor system used for coal handling at COREX Plant, JSW Steel Vijayanagar Ltd. where the component experienced a rotating-bending fatigue fracture near a geometric transition region. Metallurgical and mechanical characterization confirmed that the shaft was not manufactured from the specified quenched-and-tempered EN19 (42CrMo4) chromium–molybdenum steel. Instead, the component was produced from a low-alloy plain carbon steel in an untreated ferrite–pearlite condition, possessing substantially lower strength and fatigue resistance than required for service. Chemical composition analysis showed markedly reduced alloying content, with chromium and molybdenum measuring only 0.13% and 0.002%, respectively—far below the EN19 requirements of 0.90–1.40% Cr and 0.20–0.40% Mo. Hardness measurements ranged from 180 to 203 BHN, corresponding to an annealed/as-rolled condition, and well below the 280–320 BHN expected for a properly quenched-and-tempered EN19 shaft. Microstructural evaluation confirmed a ferrite–pearlite morphology with no evidence of tempered martensite, while inclusion analysis (ASTM E45) indicated elevated alumina and globular oxide inclusions (up to B = 1.0 and D = 1.5 ratings). Fractographic examination identified multiple ratchet marks and fatigue striations originating at the shaft surface, consistent with high-cycle fatigue under cyclic bending stresses. The combined effects of incorrect material grade, absence of heat treatment, and poor steel cleanliness significantly reduced fatigue resistance, ultimately leading to shaft failure. Recommendations include mandatory verification of material certification, quench-and-temper processing, steel cleanliness specifications, and alignment checks to enhance shaft reliability in future installations.