Flow drill screw

A flow drill screw, comprising a head, a threaded section of a rod, and a tip portion,

• wherein the head is configured to connect with an external tool;
• the threaded section of the rod is configured for self-tapping a plate, and a through hole is provided at a central axis position of the threaded section of the rod;
• one end of the through hole is extended to an end face of the tip portion, and the other end of the through hole is extended to the head to communicate with an outside world;
• the tip portion is configured to penetrate the plate, and the tip portion is made of tungsten steel alloy material;
• the threaded section of the rod and the tip portion are made of different metal materials and ends of the threaded section of the rod and the tip portion are connected and fixed by welding;
• and
• fixing the flow drill screw to a steel plate comprises:
• a tool is used to clamp the head of the screw, the other end of the screw abuts against the steel plate and kept perpendicular to the steel plate;
• at the same time, the tool is provided with a top pressing rod passing through the through hole, and an end of the top pressing rod abuts against an end face of the tip portion;
• the threaded section of the rod is under the same force as the tip portion, and the threaded section of the rod is not bend relative to the tip portion;
• pressure is applied to the screw with the tool;
• end faces of the head and the tip portion of the screw that are connected with the steel plate are simultaneously subjected to pressure, and the pressure is concentrated at a contact point between the tip portion and the steel plate, thereby forming a recess fixing point on the steel plate;
• and
• the tool is used to rotate the screw and continuously apply pressure to the steel plate, thereby creating a frictional force between the steel plate and the tip portion;
• the tip portion is made of tungsten steel alloy material, and the tip portion withstands temperatures up to 1000° C.;
• during this process, the steel plate is in a hot red and soft state, so that the tip portion penetrates the steel plate;
• at the same time, when the steel plate is in a hot red state, the threaded section of the rod abuts against the steel plate, rendering it easier for the steel plate to form threads.