【摘要】 针对某超大采高支护装备连接头发生的弯曲失效问题，通过宏观形貌观察、化学成分分析、微观组织检验、力学性能测试及断口形貌分析等方法系统研究了失效机理。结果表明连接头失效的主要原因是材料碳含量偏低(低于设计标准)及热处理工艺不当导致的工件硬度不合格。基于此，提出以下改进方案：(1)原材料控制：建立进厂材料碳含量快速检测机制，采用直读光谱仪进行100%检测，确保碳含量符合质控指标；(2)最佳优化工艺为：采用阶梯式热处理工艺，工件在<300℃时装炉，以≤60℃/h升温至600℃保温60 min,再以≤150℃/h升温至920℃保温120 min后水淬；淬火后2 h内进行回火处理，在≤280℃装炉，以≤130℃/h升温至540℃保温3.5 h后水冷。工艺改进后，连接头的强度和硬度均匀性显著提高，经工程验证，改进后的产品在服役周期内未再发生弯曲失效现象。更多还原

【Abstract】 In response to the bending failure problem of the connection head of a certain ultra large mining support equipment, the failure mechanism was systematically studied through macroscopic morphology observation, chemical composition analysis, microstructure inspection, mechanical property testing, and fracture morphology analysis. The results indicate that the main reason for the failure of the connector is the low carbon content of the material(lower than the design standard) and improper heat treatment process, which leads to the unqualified hardness of the workpiece. Based on this, the following improvement plan is proposed:(1) Raw material control: A rapid detection mechanism for carbon content of incoming materials is established, a direct reading spectrometer for 100% detection is used, and ensuring that the carbon content meets the quality control standards.(2) The optimal optimization process: A stepped heat treatment process is adopted, the workpiece is loaded into the furnace below 300 ℃, heated to 600 ℃ at a rate of ≤60 ℃/h for 60 min, and then heated to 920 ℃ at a rate of ≤150 ℃/h for 120 min before quenching with water. Tempering treatment shall be carried out within 2 h after quenching, and the furnace shall be loaded below 280 ℃. The temperature shall be raised to 540 ℃ at a rate of ≤130 ℃/h, maintaining for 3.5 h and then water cooling. After the process improvement, the strength and hardness uniformity of the connector are significantly improved. Through engineering verification, the improved product does not experience bending failure again during its service life.更多还原