Ishikawa Gasket Co., Ltd.

Takanobu Yokoyama

Kisho Yasuda

A gasket includes at least one metal plate formed of a martensitic stainless steel plate and clamped between two members fastened by fastening devices, a cylinder bore provided in the metal member, a seal bead protruding outwardly from a flat surface of the metal plate, and annularly surrounding the cylinder bore, the seal bead having a top portion and two side portions arranged at two sides of the top portion, and insertion holes for the fastening devices to pass through, provided around the cylinder bore. The seal bead has a high hardness portion having a hardness higher than that in a portion of the metal plate other than the high hardness portion. The high hardness portion has a thickness gradually reduced toward a boundary between the high hardness portion and the portion other than the high hardness portion.

Gasket equipped with bead with different hardness

A gasket includes at least one metal plate to be clamped between two members fastened by fastening devices, an opening portion corresponding to a sealing hole provided in the at least one metal member, a seal bead protruding outwardly from a flat surface of the at least one metal plate, and annularly surrounding the opening portion, and insertion holes through which the fastening devices pass. At least one metal plate is formed by a martensitic stainless steel plate, and a high hardness portion having a hardness higher than that of the stainless steel plate is formed in at least one portion of the seal bead formed in the stainless steel plate.

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Utsunomiya, Japan

Takanobu Yokoyama