Austenitic stainless steel sheet for gasket, and gasket
To provide a heat resistant metal gasket that is controlled to have a strength level (ordinary temperature hardness) capable of facilitating processing, and has excellent gas leak resistance. An austenitic stainless steel sheet for a metal gasket, having a chemical composition containing from 0.015 to 0.200% of C, from 1.50 to 5.00% of Si, from 0.30 to 2.50% of Mn, from 7.0 to 17.0% of Ni, from 13.0 to 23.0% of Cr, and from 0.005 to 0.250% of N, all in terms of percentage by mass, containing, as necessary, at least one of Mo, Cu, Nb, Ti, V, Zr, W, Co, B, Al, REM (rare-earth element except for Y), Y, Ca and Mg, with the balance of Fe and unavoidable impurities, having an ordinary temperature hardness of 430 HV or less, having a half width of a peak of an austenite crystal (311) plane in an X-ray diffraction pattern of a cross section perpendicular to a sheet thickness direction of from 0.10 to 1.60°, and having a surface roughness Ra of 0.30 μmm or less.
1. An austenitic stainless steel sheet for a metal gasket, having a chemical composition containing from 0.015 to 0.200 % of C, from 1.50 to 5.00% of Si, from 0.30 to 2.50% of Mn, from 7.0 to 17.0% of Ni, from 13.0 to 23.0% of Cr, and from 0.005 to 0.250% of N, all in terms of percentage by mass, with the balance of Fe and unavoidable impurities, having an ordinary temperature hardness of 430 HV or less, having a half width of a peak of an austenite crystal (311) plane in an X-ray diffraction pattern of a cross section perpendicular to a sheet thickness direction of from 0.60 to 1.60°, and having a surface roughness Ra of 0.30 μm or less.
2. The austenitic stainless steel sheet for a metal gasket according to claim 1 , wherein the austenitic stainless steel sheet has a chemical composition further containing at least one of 2.00% or less of Mo, 4.00% or less of Cu, 0.80% or less of Nb, 0.50% or less of Ti, 1.00% or less of V, 1.00% or less of Zr, 3.00% or less of W, 3.00% or less of Co, and 0.020% or less of B, all in terms of percentage by mass.
3. The austenitic stainless steel sheet for a metal gasket according to claim 1 , wherein the austenitic stainless steel sheet has a chemical composition further containing at least one of 0.20% or less of Al, 0.20% or less of REM (i.e., rare-earth element except for Y), 0.20% or less of Y, 0.10% or less of Ca, and 0.10% or less of Mg, all in terms of percentage by mass.
4. The austenitic stainless steel sheet for a metal gasket according to claim 1 , wherein the austenitic stainless steel sheet has a difference ΔHV between an ordinary temperature hardness and a high temperature hardness at 700° C. of 300 HV or less.
5. The austenitic stainless steel sheet for a metal gasket according to claim 1 , wherein the austenitic stainless steel sheet has a sheet thickness of from 0.10 to 0.40 mm.
6. A metal gasket comprising the austenitic stainless steel sheet for a metal gasket according to claim 1 having been formed, the metal gasket having a bead formed by press forming, and being used by pressing an apex of the bead onto an opposite contact material.
7. The metal gasket according to claim 6 , wherein the metal gasket is used at a temperature of from 600 to 800° C.
8. The metal gasket according to claim 6 , wherein the metal gasket is used for sealing a combustion gas of an internal combustion engine.