Production method for stabilizers

A production method for stabilizers, the method comprising:

• forming a steel bar material into a product shape by bending, the steel bar material being a manganese boron steel containing at least C:
• more than 0.20 wt % to 0.39 wt %, Mn:
• 0.50 wt % to 1.70 wt %, B:
• 0.0005 wt % to less than 0.001 wt %, and Si:
• 0.05 wt % to 0.40 wt % as essential elements, the steel bar material further comprises P:
• 0.040% or lower and S:
• 0.040% or lower as inevitably included impurity elements;
• at least one element selected from a group consisting of Ni:
• 0.30% or lower, Cr:
• 1.20% or lower, Cu:
• 0.30% or lower, Mo:
• 0.08% or lower, V:
• 0.30% or lower, Ti:
• 0.05% or lower, Nb:
• 0.06% or lower, Al:
• 0.30% or lower, N:
• 0.02% or lower, Ca:
• 0.40% or lower, and Pb:
• 0.40% or lower as optional additive elements;
• and a remainder containing Fe and other inevitably included impurity elements;
• heating the bent steel bar material at a temperature between 850° C. and 1100° C. for austenitizing;
• quenching the bent steel bar material in a medium having a heat transfer coefficient higher than or close to that of water, the quenching of the heated bent steel bar material being performed at a critical cooling rate or above in a medium of water, water solution with polymer, or salt water having a heat transfer coefficient higher than or close to that of water;
• preheating the quenched steel bar material that is not shot-peened in a range of 180° C. to 200° C.;
• coating the preheated steel bar material with a coating material, the coating material including an epoxy resin powder;
• and
• post-heating the coated coating material at a temperature in a range of 180° C. to 200° C.,
• wherein the stabilizer to be produced includes a metal texture of which 90% or higher is formed of a quench-induced martensite texture, and
• wherein a stabilizer is produced of the quenched steel bar material without being tempered.