Description

Recent research activities have shown that for improving the strength and forming behaviour of oil-hardened and tempered spring steel wire the tempering processes of both wire and spring production need to be adjusted. In a newly developed laboratory heat treatment device 3 different qualities of wire of 2 different diameters each were hardened and tempered with a large quantity of tempering and time parameters. All hardened and tempered (wire production) samples were then tempered in a second tempering process (spring production) in order to achieve their final quality (especially strength). In order to provide parameters for manufacturing springs, nominal values for the variously-treated samples of wire, tensile and torsion tests were determined. The paper presents an overview of the necessary changes in respect of the tempering processes of wire and spring production; also the values found for wire and spring parameters (e.g. torsional yield stress, tensile strength, presetting behaviour or fatigue of helical compression springs).