Cladding method for valve seat and production method for cylinder head

A production method for a cylinder head, comprising:

• a first step of forming a cylinder head blank provided with an intake port and an exhaust port communicating with a combustion chamber;
• a second step of forming an annular countersunk groove in an opening end of at least one of the intake port and the exhaust port on a combustion chamber side;
• a third step of providing a gas flow regulating wall projecting from the annular countersunk groove to an inner side of the annular countersunk groove and to the combustion chamber side, the gas flow regulating wall having an upper surface that faces toward the combustion chamber side and that inclines upwardly as the upper surface progresses from an edge of the annular countersunk groove toward a center of the annular countersunk groove;
• a fourth step of forming a cladding layer for a valve seat by supplying metal powder in the annular countersunk groove, and spraying gas to the metal powder and flowing the gas by the upper surface of the gas flow regulating wall from the inner side to an outer side of the annular countersunk groove, while the metal powder is irradiated with a laser beam, the flowing of the gas pushing the cladding layer in a molten state toward the outer side of the annular countersunk groove;
• and
• removing the gas flow regulating wall from the cylinder head blank after the fourth step.