本规范涵盖了有头螺栓、螺钉和螺柱的颗粒流动模式要求。螺栓、螺钉或螺柱制造中的镦粗实践决定了晶粒流动模式，但它也受到紧固件设计的很大影响。

This specification covers the grain flow pattern requirements in headed bolts, screws, and studs. The heading practice in the manufacture of the bolt, screw, or stud sets the grain flow pattern, but it is also greatly influenced by the fastener design.