A METHOD FOR SHOT PEENING

• Main Authors: KATO, Makio, KOBAYASHI, Yuji, ISHIKURA, Ryohei, KANO, Takashi, UJIHASHI, Satoru, OKUMURA, Kiyoshi
• Format: Patent
• Language: English; French; German
• Published: 26.09.2018
• Subjects: ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL; CHEMISTRY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; GRINDING; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; POLISHING; TRANSPORTING

The object of the present invention is to provide a method for shot peening by which a compressive residual stress that is higher than any achieved by the conventional method can be achieved while the thickness of the processed material that is scraped is suppressed. The method is characterized in that the shot materials are shot against the processed material that has the hardness of 750 HV or more that is calculated from equations (1) to (3) below. The shot materials have Vickers hardness that is higher than the hardness of the processed material by 50HV to 250 HV. The thickness of the processed material that is to be scraped is suppressed to 5 µm or less. HV m = f C - f T t ¢ 1 - ³ R / 100 + 400 × ³ R / 100 f C = - 660 ¢ C 2 + 1373 ¢ C + 278 f T t = 0.05 ¢ T ¢ logt + 17 - 318 where C denotes the C (carbon) content in the surface layer that is achieved by carburizing (mass %), T denotes the tempering temperature (K), t denotes the tempering time (hr), and ³ R denotes the amount of residual austenite (vol. %).