| 摘要 |
PURPOSE:To easily manufacture the spring flat wire being excellent in fatigue resistance form a round wire rod by setting surface roughness to a specific value range by performing peripheral surface grinding to the round wire rod, and thereafter, performing cold working for forming it to a flat wire rod in which a ratio to thickness dimensions of width dimensions is a specific value or above. CONSTITUTION:By performing peripheral surface grinding to a round wire rod W by a grinding device 1 in which a grinding roll 2 is placed, its surface roughness is set to Rmax 1-5mum, and thereafter, cold working for forming a flat wire rod in which a ratio of width dimensions to thickness dimensions is >=15 folds is performed. Cold working to the flat wire rod contains cold rolling executed plural times for working in the vertical direction from both the upper and the lower faces, a cold working process of once or more, in which reduction of area in the horizontal direction is 1.5-15%, and a working process for making round to a corner part of the side face. In the end, a side face grinding process for forming the surface roughness of the side face to Rmax 1-3mum is provided. In such a way, a spring flat wire which is excellent in fatigue resistance, and also, in which the surface roughness of the side face is satisfactory can be manufactured easily from the round wire rod. |
