| 摘要 |
<p>First in a determination process the presence or absence of a nitride layer on the surface of a cooling water hole (42) of a die (40) is determined by a determination unit (48) using an eddy current sensor (46). Next in a shot process when the result determined in the determination process is an absence of a nitride layer shot peening is performed on the surface of the cooling water hole (42) of the die (40) under shot conditions that are established according to the base metal of the die (40). When the result determined in the determination process is the presence of a nitride layer shot peening is performed on the surface of the cooling water hole (42) of the die (40) under shot conditions that maintain the presence of the nitride layer.</p> |
