COMPOSITE MAGNETIC MATERIAL HAVING FERROMAGNETIC PART AND NONMAGNETIC PART AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a composite magnetic material having a high detection sensitivity and improved strength by preparing a steel having a componental compsn. contg. specified ratios of C, Si, Mn, Ni, Cr, Mo and Al and satisfying specified Md30 value and equivalent Heq value and having a specified ferromagnetic part and nonmagnetic part. SOLUTION: A composite magnetic material having a componental compsn. of steel contg., by weight, =0.1%, C, =1.0% Si, =1.5% Mn, 6.0 to 12.0% Ni, 12.0 to 20.0% Cr, =2.0% Mo, 0.5 to 2.0% Al, and the balance Fe with inevitable impurities and satisfying the formula of Angel: md30=413-462(C%+N%)-92(Si%)-8.1(Mn%)-13.7 (Cr%)-9.5(Ni%)-18.5(Mo%)=20 to 90 deg.C and the Ni equivalent of the formula of Hirayama Heq=(Ni%)+1.05(Mn%)+0.65(Cr%)+0.36(Si%)+12.6(C%)=19 to 23% and having a ferromagnetic part with =0.3T magnetic flux density B50 and a nonmagnetic part with =1.2 permeability is prepd.