螺纹零件和紧固件是要求具有高度互换性的机械零件。近两年来,通过机车车辆螺纹公制化工作,互换程度已大大提高,产品质量亦显著提高,过去存在的修配现象已有改善,尤其是在公制化过程中大量采用了外购紧固件,其质量高,用料省,可以达到互 Threaded parts and fasteners are mechanical parts that require a high degree of interchangeability. In the past two years, the degree of interchange has been greatly enhanced through the work of standardizing the screw thread of locomotives and rolling stock, the quality of products has also been significantly improved, and the existing repairs have been improved. In particular, extensive use of purchased fasteners in the process of standardization, Its high quality, materials, can reach each other