| 摘要 |
PURPOSE:To reduce the distortion of current through realizing a linear minor loop, by forming a pole piece and a yoke piece in one body by a cold forging from the aluminum killed steel containing 0.06-0.15% carbon. CONSTITUTION:A heat process is applied e.g. at 600 deg.C+ or -10 deg.C for 60+ or -10 minutes to alminum killed steel (0.06-0.15% carbon) as a blank material to form a pole piece 11 and a yoke piece 12 to one body of a prescribed shape by a cold forging. Thus a minor loop is made linear in this pole yoke, and as a result the distortion of current is reduced to enhance the tone quality. |
