抗拉强度1100 MPa以上钢质无缝气瓶的疲劳特性研究

Study on Fatigue Characteristics of Steel Seamless Gas Cylinders with Tensile Strength Exceeding 1100 MPa

摘要: 本研究针对抗拉强度1100 MPa以上的钢质无缝气瓶，以其常用材料34CrMo₄H为研究对象，系统开展成分优化、拉伸力学性能测试、有限元应力分析及疲劳寿命预测等工作。通过实验获取34CrMo₄H材料的S-N曲线并拟合疲劳寿命方程，明确周向应力为主要应力分量、疲劳裂纹易沿轴向萌生扩展；基于有限元模型模拟内压循环载荷下的应力状态，结合抽样试验验证模型准确性——实际疲劳寿命与预测结果处于同一数量级，裂纹萌生位置与模拟的最大周向应力集中区域完全一致。研究结果揭示了该类气瓶在复杂载荷下的失效机理，为其全生命周期监测方案(包括监测方法与关键位置布设)提供数据支撑，深化了对1100 MPa级钢质无缝气瓶疲劳寿命特性的认知，助力我国高端钢质无缝气瓶的工程化应用与安全保障水平提升。

Abstract: This study systematically investigates steel seamless gas cylinders with tensile strength exceeding 1100 MPa, focusing on their common material 34CrMo₄H. It conducts composition optimization, tensile mechanical property testing, finite element analysis (FEA), and fatigue life prediction. Experimental results derive the S-N curve and fatigue life equation for 34CrMo₄H, identifying hoop stress as the primary stress component and axial fatigue crack initiation/propagation. FEA simulates stress under cyclic internal pressure, verified with sampling tests—actual fatigue life matches predictions in order of magnitude, and crack positions align with maximum hoop stress concentration areas. Findings reveal failure mechanisms of such cylinders under complex loading conditions, provide data support for full-life cycle monitoring plans (including monitoring methods and critical location deployment), deepen understanding of 1100 MPa-grade cylinder fatigue life characteristics, and advance engineering application and safety assurance level of China’s high-end steel seamless gas cylinders.