1概述螺纹是机械零件用于紧固、连接、传动及传递位移的一种基本结构形式。螺纹的种类很多,而且各国的螺纹标记方法和代号又不完全一致。随着世界制造业向中国的转移,在引进资料、引进设备或承接的国外订单中,经常会遇到五六十年代甚至更久远的螺纹结构,这些螺纹在代号、公差及 1 Overview Threads are a mechanical part used to fasten, connect, drive and transfer displacement of a basic structure. There are many types of threads, and the thread marking methods and codes of different countries are not exactly the same. As the manufacturing industry in the world shifts to China, it often encounters screw threads of the fifties and sixties or even longer when it comes to importing materials, importing equipment or undertaking foreign orders. These threads are often used in codes, tolerances and