ASTM A240 Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications.ASTM A240 Standard main steel grade: ASTM A240 329(S32900),ASTM A240 2507(S32750),ASTM A240 2205(S32205),ASTM A240 410(S41000) and so on.