| 摘要 |
PROBLEM TO BE SOLVED: To improve the corrosion resistance and wear resistance of a steel member without causing its deformation and the cracking and peeling of a film by coating the steel member surface with a boriding treating agent, executing heating to form a compd. of iron and boron and introducing gas from the outside at one time of the heating or cooling. SOLUTION: The surface of a steel member such as large steel parts or the like is coated with a boriding treating agent contg. a boron supplying source and a boriding accelerator, which is heated at about 900 deg.C to form a compd. of iron and boron. As the boron feeding source, amorphous boron, FeB, B4C, borax or the like are used. Moreover, as the boriding accelerator, NH4, Cl, KBF4 or the like is used, and, preferably, it is used jointly with a boriding conditioner. In this boriding treatment, at the time of the heating and/or cooling, gas is introduced from the outside. This gas introduction is executed preferably at the time between the start of the boriding or the finishing temp. and the maximum treating temp. Moreover, as the introducing gas, inert gas or reducing gas is preferable. In this way, the prolongation of the service life of a steel member such as parts in a bath of a continuous hot dip metal plating device or the like can be attained.
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