十、螺纹有哪几种?目前我们使用的螺纹可以分为两大类:一类是标准螺纹,另一类是非标准螺纹。标准螺纹使用非常普遍,互换性也很高,常用的有以下几种:普通螺纹,又分粗牙普通螺纹、细牙普通螺纹;英制螺纹,常用的有英制55°和美制60°;管螺纹,又分圆柱管螺纹、圆锥管螺纹、英制管螺纹;梯形螺纹;锯齿形螺纹。非标准螺纹有方牙螺纹、平面螺纹等,但很少使用。此外,当前国外引进的设备有各国不同标准的螺纹,配制时应查有关标准。 X. What kinds of threads? At present, we can use the thread can be divided into two categories: one is the standard thread, and the other is a non-standard thread. The standard thread is very common, interchangeability is also high, commonly used in the following categories: ordinary thread, sub-ordinary coarse thread, fine thread ordinary thread; British thread, commonly used in English 55 ° and US 60 °; tube Thread, and sub-cylindrical pipe thread, tapered pipe thread, British pipe thread; trapezoidal thread; serrated thread. Non-standard thread square thread, flat thread, etc., but rarely used. In addition, the current foreign equipment imported countries have different standards thread, the preparation should check the relevant standards.