bolt（螺栓）和screw（螺钉）有什么区别

说法比较多,仅供参考：一、有无螺母（本人及多数人观点）螺钉一般是直接上在某件工件上,螺栓一般和螺母配合,做连接与紧固。二、受力方式（某资料定义）1、工具在圆周旋动的是螺栓,2、工具在圆心旋动的是螺钉,3、不能使用工具旋动的是螺柱。三、look（英文的定义）螺栓(bolt)定义是：headed fasteners having external threads that meet an exacting,uniform bolt thread specification (such as M,MJ,UN,UNR,and UNJ) such that they can accept a nontapered nut（螺母）。螺钉（screw)的定义是:Screws are defined as headed,externally-threaded fasteners that do not meet the above definition of bolts。