| 摘要 |
PROBLEM TO BE SOLVED: To provide a diaphragm, a diaphragm valve and a method for manufacturing the diaphragm capable of increasing a flow rate (Cv value) of gas without degrading long-term durability even when a displacement amount is increased.SOLUTION: The diaphragm 1 has an outer diameter Φ of 10 to 35 mm and includes a dome portion 1D in a dome shape and a flange portion 1T formed continuously at a peripheral edge of the dome portion 1D via a boundary portion 1K, the boundary portion 1K has a radius of curvature R of 0.6 mm or more on a convex side of the dome portion 1D, and the diaphragm is formed of a cobalt-based super-alloy of which composition range in mass ratio is cobalt 30-45%, nickel 10-20%, chromium 5-20%, tungsten 3-5%, molybdenum 3-9%, iron 1-40%, containing unavoidable impurities. |
