| 摘要 |
PROBLEM TO BE SOLVED: To prevent cracking of a die attributable to the stress corrosion cracking, and to improve the service life of the die by executing the corrosion resistant electroless plating on an internal cooling hole of the die for the hot working to control generation of the stress corrosion cracking. SOLUTION: The electroless plating solution is poured in an internal cooling hole 5 in a die for hot working in which the nitriding treatment, etc., is completed after the diesinking is performed on a surface to be worked, and heated to the prescribed temperature to execute the uniform plating in the hole. In a case of a die using hot tool steel SKD 61, the internal cooling hole is pre- treated such as by pickling, the NiP electroless plating solution is poured into the cooling hole, and the die is charged into a thermostatic oven provided with an exhaust device, and preferably heated and kept at 80 deg.C to perform the plating. The plating solution is removed, the die is rinsed in water, and heated around 200 deg.C for drying. The plated film of around 15μm in film thickness and excellent in the close adhesion having no holes can be formed.
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