"Standard Specification for  Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service" .
Scope: wrought carbon steel and alloy steel fittings of seamless and welded.

Grade and Marking Symbol	Chamical Composition Requirement, %
	Carbon	Manganese	Phospho- rus, max	Sulfur, max	Silicon	Chromium	Molybdenum	Nickel	Copper	Others
WPB	0.30 max	0.29–1.06	0.05	0.058	0.10 min	0.40 max	0.15 max	0.40 max	0.40 max	Vanadium 0.08 max
WPC	0.35 max	0.29–1.06	0.05	0.058	0.10 min	0.40 max	0.15 max	0.40 max	0.40 max	Vanadium 0.08 max
WP1	0.28 max	0.30–0.90	0.045	0.045	0.10–0.50	-	0.44–0.65	-	-	-
WP12 CL1 WP12 CL2	0.05–0.20	0.30–0.80	0.045	0.045	0.60 max	0.80–1.25	0.44–0.65	-	-	-
WP11 CL1	0.05–0.15	0.30–0.60	0.03	0.03	0.50–1.00	1.00–1.50	0.44–0.65	-	-	-
WP11 CL2 WP11 CL3	0.05–0.20	0.30–0.80	0.04	0.04	0.50–1.00	1.00–1.50	0.44–0.65	-	-	-
WP22 CL1 WP22 CL3	0.05–0.15	0.30–0.60	0.04	0.04	0.50 max	1.90–2.60	0.87–1.13	-	-	-
WP24	0.05–0.10	0.30–0.70	0.02	0.01	0.15–0.45	2.20–2.60	0.90–1.10	-	0.75–1.25	Aluminum 0.020 Boron 0.0015–0.0070 Nitrogen 0.12 Titanium 0.06–0.10 Vanadium 0.20–0.30
WP5 CL1 WP5 CL3	0.15 max	0.30–0.60	0.04	0.03	0.50 max	4.0–6.0	0.44–0.65	-	-	-
WP9 CL1 WP9 CL3	0.15 max	0.30–0.60	0.03	0.03	1.00 max	8.0–10.0	0.90–1.10	-	-	-
WPR	0.20 max	0.40–1.06	0.045	0.05	-	-	-	1.60–2.24	0.75–1.25	-
WP91	0.08-0.12	0.30–0.60	0.02	0.01	0.20–0.50	8.0–9.5	0.85–1.05	0.40 max	-	Vanadium 0.18–0.25 Columbium 0.06–0.10 Nitrogen 0.03–0.07 Aluminum 0.02 Titanium 0.01 Zirconium 0.01 Vanadium 0.18–0.25 Columbium 0.060–0.10 Nitrogen 0.04–0.09 Aluminum 0.02 max Boron 0.0003–0.006 Tungsten 0.90–1.10 Titanium 0.01 max Zirconium 0.01 max Aluminum 0.02F Boron 0.001–0.006 Columbium 0.04–0.09 Nitrogen 0.030–0.070 Titanium 0.01 Tungsten 1.50–2.00 Vanadium 0.15–0.25 Zirconium 0.01F
WP911	0.09-0.13	0.30–0.60	0.02	0.01	0.10–0.50	8.5–9.5	0.90–1.10	0.40 max	-
WP92	0.07–0.13	0.30–0.60	0.02	0.01	0.5	8.50–9.50	0.30–0.60	0.4	-

Elongation Requirements
Elongation: Standard round specimen, or small proportional specimen, min % in 4 D； Rectangular specimen for wall thickness 5⁄16 in. [7.94 mm] and over, and for all small sizes tested in full section; min % in 2 in. [50 mm]. Rectangular specimen for wall thickness less than 5⁄16 in. [7.94 mm]; min % in 2 in. [50 mm] (1⁄2-in. [12.7-mm] wide specimen)						Grade
						All Grades except WPR, WP91, and WP911		WPR and WP24		WP91
										WP92
										WP911
						Longitudinal	Transverse	Longitudinal	Transverse	Longitudinal	Transverse
						22	14	20	-	20	13
						30	20	28	-	-	-
									-	-	-

Wall Thickness				Grades
				All Grades except WPR, WP91 and WP911				WPR		WP91, WP92, and WP911
in.		[mm]		Longitudinal		Transverse		Longitudinal		Longitudinal
5⁄16   (0.312)		7.94		30		20		28		20
9⁄32   (0.281)		7.14		28.5		19		26.5		19
1⁄4    (0.250)		6.35		27		18		25		18
7⁄32   (0.219)		5.56		25.5				23.5		17
3⁄16   (0.188)		4.76		24				22		16
5⁄32   (0.156)		3.97		22.5				20.5		15
1⁄8    (0.125)		3.17		21				19		14
3⁄32   (0.094)		2.38		19.5				17.5		13
1⁄16   (0.062)		1.59		18				16		12