Abstract
Self-tapping screws are currently very popular fasteners. They found their application for joining metal, wood and plastic. The design of self-tapping screws is diverse. The quality of the applied metal has the greatest impact on the quality of the screws. To fulfill the requirements for geometric parameters and mechanical properties, high-quality raw materials are required. Production of high-quality wire for the further stamping of self-tapping screws is an urgent task in the conditions of the modern market. The article presents the grades of steel used abroad and in Russia. The technological process of wire drawing for stamping self-tapping screws is considered. The features of wire manufacturing technology for subsequent cold stamping of self-tapping screws in the conditions of OJSC “MMK-METIZ” are presented. Recommended mechanical properties of wire rod and finished wire are given for obtaining screw heads during upsetting and high-quality thread during knurling. Alloying elements in the metal will provide mechanical properties on the finished screws after heat treatment. Recommendations are given on the selection of dry drawing lubricants, allowing to improve the surface quality of the finished wire. A new technology of manufacturing of wire with phosphating and subsequent wet drawing is presented.
Keywords
Wire, self-tapping screws, drawing, cold forging, the degree of deformation, compression.