车用尼龙12（PA12）管在典型工作条件下的性能稳定性对于汽车油管的可靠性至关重要。文章旨在探究温湿度条件对PA12管的尺寸特性及力学性能的影响因素。将4种PA12管在6种不同温湿度条件下进行梯度时间处理后，进行一系列力学性能试验，具体分析温湿度及处理时间对4种PA12管的长度、直径变化率和拉伸强度的影响规律。结果表明：较高的温湿度及较长的处理时间会导致更大的尺寸变化，且PA12五层管的尺寸变化率明显低于单层管及双层管；随着温湿度的升高及处理时间的延长，拉伸强度整体呈现下降趋势，五层管拉伸强度变化较为稳定；相较于湿度变化，温度对PA12管拉伸性能的影响程度较低。研究结果将为PA12材料在汽车工业的应用提供参考。

The performance stability of automotive nylon 12 (PA12) tube under typical working conditions is very important for the reliability of automotive tube. The paper aims to explore the influence factors of temperature and humidity conditions on the dimensional characteristics and mechanical properties of PA12 tube. After gradient time treatment of four kinds of PA12 tubes under six different temperature and humidity conditions, a series of mechanical properties tests were carried out, and the effects of temperature and humidity and treatment time on the length, diameter change rate and tensile strength of four kinds of PA12 tubes were analyzed. The results show that higher temperature and humidity and longer treatment time will lead to greater dimensional change, and the dimensional change rate of PA12 five-layer tube is significantly lower than that of single-layer tube and double-layer tube. With the increase of temperature and humidity and the extension of treatment time, the tensile strength of the five-layer tube showed a decreasing trend, and the change of tensile strength of the five-layer tube was stable. The influence of temperature on the tensile properties of PA12 tube is lower than that of humidity. The research results provide a reference for the application of PA12 material in automotive industry.