IRON BASE ALLOY PLATE MATERIAL FOR VOICE COIL MOTOR MAGNETIC CIRCUIT YOKE AND YOKE FOR VOICE COIL MOTOR MAGNETIC CIRCUIT

摘要

An iron alloy strip for a voice coil motor magnetic circuit yoke is provided to obtain a high magnetic flux density, omit the formation of a corrosion resistant metal coating by maintaining excellent corrosion resistance, and manufacture the iron alloy strip at a low cost, and a yoke for a voice coil motor magnetic circuit made using the iron alloy strip for a voice coil motor magnetic circuit yoke is provided. In a strip for a yoke, in which a strip used for a voice coil motor magnetic circuit has a thickness of 0.1 to 5 mm and a magnetic field strength variation within the strip of 0 to 10 Hz, an iron alloy strip for a voice coil motor magnetic circuit yoke is characterized in that the strip is an iron alloy containing respective elements of 0.0001 to 0.02 wt.% of C, 0.0001 to 5 wt.% of Si, 0.001 to 0.2 wt.% of Mn, 0.0001 to 0.05 wt.% of P, 0.0001 to 0.05 wt.% of S, 0.0001 to 5 wt.% of Al, 0.001 to 0.1 wt.% of O and 0.0001 to 0.03 wt.% of N with Co and Cr being not contained or contained as inevitable impurities in practical use, and containing 0.01 to 5 wt.% in total of at least one alloy element selected from Ti, Zr, Nb, Mo, V, Ni, W, Ta and B as adding elements with the balance being Fe in addition to inevitable impurities in practical use, and the strip has a saturation magnetic flux density of 1.7 to 2.3 Tesla, a maximum relative permeability of 1,200 to 22,000, and a coercive force of 20 to 380 A/m.