Scholarlink

<p>Large excavators are critical assets in large-scale mining operations, relying on gearboxes to transmit mechanical energy during lifting and digging activities. Gear tooth failures in these systems lead to high maintenance costs and unplanned downtime, constituting a significant operational challenge. Understanding the root causes of such failures is essential for improving reliability and performance, as gear durability is governed by the interaction between metallurgical characteristics, heat treatment conditions, and operational stresses. In this study, premature fractures of gear teeth in an excavator gearbox were investigated through a multiparametric analysis. Chemical composition was determined by optical emission spectroscopy, confirming compliance with DIN 18CrNiMo 7-6 steel. Optical and scanning electron microscopy revealed the presence of retained austenite, untempered martensite, and cementite along grain boundaries, as well as multiple fatigue crack initiation sites and characteristic propagation striations. Microhardness profiling indicated heterogeneous case-hardened layers with the coexistence of martensitic and retained austenitic phases, while field vibration measurements demonstrated operational stress levels exceeding recommended limits, thereby accelerating fatigue crack propagation. Despite the chemical composition meeting material specifications, the root cause of failure was attributed to excessive retained austenite resulting from insufficient carbon potential during the carburizing process. Under cyclic loading, the retained austenite transformed into martensite, promoting material embrittlement and intensifying high cycle fatigue crack propagation until catastrophic failure occurred. These findings highlight the critical interplay between microstructure, heat treatment, and operational conditions, underscoring the need to optimize carbon potential, carburizing parameters, and vibration control to enhance the reliability of gear systems used in mining applications.</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 and Characterization in Large Excavator Speed Reducer

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年3月11日

查看全文
  • Tiago Soares da Silva,
  • Luciano Volcanoglo Biehl,
  • José Cleber Rodrigues da Silva,
  • Demostenes Ferreira Filho,
  • Jorge Luis Braz Medeiros

摘要

Large excavators are critical assets in large-scale mining operations, relying on gearboxes to transmit mechanical energy during lifting and digging activities. Gear tooth failures in these systems lead to high maintenance costs and unplanned downtime, constituting a significant operational challenge. Understanding the root causes of such failures is essential for improving reliability and performance, as gear durability is governed by the interaction between metallurgical characteristics, heat treatment conditions, and operational stresses. In this study, premature fractures of gear teeth in an excavator gearbox were investigated through a multiparametric analysis. Chemical composition was determined by optical emission spectroscopy, confirming compliance with DIN 18CrNiMo 7-6 steel. Optical and scanning electron microscopy revealed the presence of retained austenite, untempered martensite, and cementite along grain boundaries, as well as multiple fatigue crack initiation sites and characteristic propagation striations. Microhardness profiling indicated heterogeneous case-hardened layers with the coexistence of martensitic and retained austenitic phases, while field vibration measurements demonstrated operational stress levels exceeding recommended limits, thereby accelerating fatigue crack propagation. Despite the chemical composition meeting material specifications, the root cause of failure was attributed to excessive retained austenite resulting from insufficient carbon potential during the carburizing process. Under cyclic loading, the retained austenite transformed into martensite, promoting material embrittlement and intensifying high cycle fatigue crack propagation until catastrophic failure occurred. These findings highlight the critical interplay between microstructure, heat treatment, and operational conditions, underscoring the need to optimize carbon potential, carburizing parameters, and vibration control to enhance the reliability of gear systems used in mining applications.