Production method for stabilizers

Patent metadata

Field	Value
Publication number	US-10995382-B2
Application number	US-201515534470-A
Country	US
Kind code	B2
Filing date	Dec 7, 2015
Priority date	Dec 8, 2014
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

The invention provides a production method for stabilizers which produces with high productivity in a compact production line, without tempering. The production method for stabilizers of the invention includes: forming a steel bar material containing at least C: 0.15 wt % to 0.39 wt %, Mn, B and Fe into a product shape by bending; and quenching the bent steel bar material in a medium having a heat transfer coefficient higher than or close to that of water.

First claim

The invention claimed is:

1. 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.

2. The production method for stabilizers according to claim 1 further comprising:
shot-peening a surface of the quenched steel bar material;
preheating the steel bar material shot-peened;
performing the coating of the preheated steel bar material with the coating material; and
performing the post-heating of the coated coating material.

3. The production method for stabilizers according to claim 2 , wherein a heating temperature in the preheating and post-heating is in a range of 180° C. to 200° C.

4. The production method for stabilizers according to claim 1 , wherein the stabilizer to be produced has a compressive residual stress of 150 MPa or higher up to 0.8 mm in depth from a surface of the steel bar material.

5. The production method for stabilizers according to claim 1 , wherein the stabilizer to be produced at a room temperature has a Rockwell hardness (HRC) over 44.5 and a Charpy impact value 30 J/cm2 or higher.

6. The production method for stabilizers according to claim 1 , wherein the steel bar is equivalent to a steel defined as 15B23 or 15B26 in Standard American Engineering.

Assignees

• Nhk Spring Co Ltd

Inventors

• KUWATSUKA Shinichiro
• OKUDAIRA Yurika
• Tange Akira
• Okada Hideki
• Takahashi Ken

Classifications

• C21D8/06

  during manufacturing of rods or wires · CPC title

• F16F1/02

  made of steel or other material having low internal friction {(characterised by their special construction from fibre-reinforced plastics F16F1/366; spring units consisting of several springs F16F3/02; making springs from wire B21F35/00)}; Wound, torsion, leaf, cup, ring or the like springs, the material of the spring not being relevant · CPC title

• C21D9/0075

  for rods of limited length (of unlimited length C21D9/52) · CPC title

• C21D9/00

  Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor · CPC title

• C22C38/60

  containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur · CPC title