METHOD FOR PRODUCING HOT-FORGED NON-HEATTREATED PART EXCELLENT IN MACHINABILITY

PROBLEM TO BE SOLVED: To provide a new forging method capable of improving the machinability of a forged product independently of a machinability improving element. SOLUTION: A steel material, which contains, by mass%, of 0.20-0.60% C, 0.10-2.00% Si, 0.30-2.00% Mn, 0.01-0.20% S, 0.05-2.00% Cr, ≤0.060% Al, 0.01-0.05% V, 0.003-0.020% N and if necessary, one or more kinds of Ti, Pb, Te, Ca, Bi, Mg, Zr and the balance Fe with impurity elements, is heated to either higher temperature of (solidus temperature) × 0.94 or 1,250°C as the lower limit temperature and in the range of ≤(liquidus temperature) × 0.98 as the upper limit temperature, and a hot-forging at the super-high temperature is applied so that ≥85% of the surface of a blank is brought into contact with dies in the range of the temperature to make the hot-forged product having ferrite and pearite structure and ≤No.25 average austenitic crystal grain size number. COPYRIGHT: (C)2005,JPO&NCIPI