| 摘要 |
PROBLEM TO BE SOLVED: To reduce the material cost and the working cost by positively reducing the treatment strain to that in oil-hardening or below, and realizing low alloy steel by improving the hardening performance in order to reduce strain and cracks by uniformly cooling steel parts and alloy parts in a steel and alloy parts hardening step. SOLUTION: Water is used for the medium for the cooling after the heating, and the flow rate thereof is set to be≥3.0 m/sec, preferably≥5.0 m/sec. A cooling device having a structure capable of preventing a material from being brought into contact with flowing water or the like at a low flow rate to cause non-uniform cooling is used before the material is charged into the medium at a predetermined flow rate. Fluctuation in the flow rate in a cooling area is set to be within±10% for the uniform cooling. COPYRIGHT: (C)2005,JPO&NCIPI
|
