Design standard: API 594 Face to face: ASME B16.0 Flanged ends: ASME B16.50 Test & Inspection: API 598 Body: ASTM A216-WCB,ASTM A351-CF8,CF8M,CF8C,CF3,CF3M Disc: ASTM A216-WCB,ASTM A351-CF8,CF8M,CF8C,CF3,CF3M Pivot:ASTM A182 Gr.F6a,ASTM A182 F22,ASTM A182-F304,F316,F321,F304L,F321,F304L,F316L Spring: AISI 9260,AISI 6150,ASTM A182-F304,F316,F321,F304L,F316L