Hirofumi Ueki

Development of Stainless Steel Wire for Springs that Acguires Black Color during the Manufacturing Process

Spring makers have worried about the distinction of spring products with similar dimension. For the solution of this problem, We have already developed steel wire for spring that develops golden color at the low-temperature annealing process and acquired a reputation. In the mean time, there are great demand for products with various colors especially black color, in the market. So, this paper reports our development of steel wire for springs that acguires black color during low-temperature annealing.The summary is descrived below.:(1) In a low-temperature annealing process, copper that exists as copper plating on stainless steel wire and zinc that exists as zinc-chromium alloy plating on copper plated stainless steel wire diffuse in the deposit to exhibit a brown color tone while chromium is oxidized to exhibit dark gray color tone. The overlap of these color tones exhibits a beautiful black color tone.(2) Mechanical properties are not deteriorated by the above platings.