Shape Rolling Process Combined with In-line Induction Heat Treatment for Rectangular Wire Die Springs

Abstract

In recent years, environmental issues and high labor costs have been receiving increasing attention. One example is the manufacturing process of conventional oil tempered shaped wire which is high cost, time-consuming and polluting. The aim of this study is therefore to attempt to solve the problems of producing this particular form of wire. In this study we investigate the shape rolling process combined with the in-line induction heat treatment process for tempered trapezoidal wire. The round wire was heated to austenitic temperature using in-line induction heating equipment, and the wire was formed into a trapezoidal shape using a tandem cantilever type rolling mill, then quenched in water and tempered. The entire sequence was carried out in a single procedure with an automated line, the above-mentioned shape rolling process was verified by means of the finite element method, and finally the tempered trapezoidal wire was coiled to a helical form, i.e., rectangular wire die springs, which then underwent fatigue testing. The results revealed that the mechanical properties and the fatigue testing results of the die springs all satisfied industrial standards. The advantages of the manufacturing process of this study are that is highly efficient, low cost, and more environmentally friendly than the conventional process.