Abstract
Ni-plated steel wire used for springs in electrical appliances and other devices has good corrosion resistance. Surface gloss as well as lubricity is required in spring cold working. To achieve both surface gloss and lubricity, a liquid lubricant was used in the final pass while soap powder lubricant was used in former passes. This basic research has been conducted to investigate the relationship between surface gloss and processing parameters in the final pass. As reported in our previous paper, the surface gloss of Ni-plated steel wire increases with an increase in the approach semi angle of the die and the effects of the number of times of dilution in an emulsion type lubricant are minimal. Thus, it is important to investigate friction coefficient and die pressure, which can affect die life, and to reveal the key parameter for surface gloss. In this paper, friction coefficient and die pressure are evaluated by finite element method and the relationships between experimental surface gloss and processing parameters are discussed.
