ASTM A234/A234M: American Society for Testing and Materials
Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
Scope: These fittings are for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures.

Chemical Composition
Grade and Marking Symbol	Composition, %
	Carbon	Manganese	Phosphorus	Sulfur	Silicon	Columbium	Molybdenum	Nickel	Copper	Others
WPB	0.30	0.29–1.06	0.05	0.06	0.10 min	0.40	0.15 max	0.40	0.40	Vanadium 0.08
WPC	0.35	0.29–1.06	0.05	0.06	0.10 min	0.40	0.15 max	0.40	0.40	Vanadium 0.08
WP1	0.28	0.30–0.90	0.05	0.05	0.10–0.50	. . .	0.44–0.65	. . .	. . .	. . .
WP12 CL1,	0.05–0.20	0.30–0.80	0.05	0.05	0.60	0.80–1.25	0.44–0.65	. . .	. . .	. . .
WP12 CL2										. . .
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,	0.05–0.20	0.30–0.80	0.04	0.04	0.50–1.00	1.00–1.50	0.44–0.65	. . .	. . .	. . .
WP11 CL3										. . .
WP22 CL1,	0.05–0.15	0.30–0.60	0.04	0.04	0.50	1.90–2.60	0.87–1.13	. . .	. . .	. . .
WP22 CL3										. . .
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,	0.15	0.30–0.60	0.04	0.03	0.50	4.0–6.0	0.44–0.65	. . .	. . .	. . .
WP5 CL3										. . .
WP9 CL1,	0.15	0.30–0.60	0.03	0.03	1.00	8.0–10.0	0.90–1.10	. . .	. . .	. . .
WP9 CL3
WPR	0.20	0.40–1.06	0.05	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	. . .	Vanadium 0.18–0.25
										Columbium 0.06–0.10
										Nitrogen 0.03–0.07
										Aluminum 0.02F
										Titanium 0.01F
										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	. . .	Vanadium 0.18–0.25
										Columbium 0.060–0.10
										Nitrogen 0.04–0.09
										Aluminum 0.02 maxF
										Boron 0.0003–0.006
										Tungsten 0.90–1.10
										Titanium 0.01 maxF
										Zirconium 0.01 maxF
WP92	0.07–0.13	0.30–0.60	0.02	0.01	0.50	8.50–9.50	0.30–0.60	0.40	. . .	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 0.01

Mechanical Properties
Grade and Marking Symbol	WPB		WPC, WP11 CL2, WP12 CL2	WP1	WP11 CL1, WP22 CL1, WP5 CL1, WP9 CL1	WPR	WP11 CL3, WP22 CL3, WP5 CL3, WP9 CL3	WP24	WP91	WP92 WP911	WP12 CL1
Tensile strength, minimum unless a range is given ksi [MPa]	60 [415]		70 [485]	55–80	60 [415]	63–88	75 [520]	85 [585]	90 [620]	90–120	60 [415]
				[380–550]		[435–605]				[620–840]
Yield strength, min, ksi [MPa] (0.2 % offset or 0.5 % extension-under-load)	35 [240]		40 [275]	30 [205]	30 [205]	46 [315]	45 [310]	60 [415]	60 [415]	64 [440]	32 [220]
					Elongation Requirements
					Grades
					All Grades except WPR, WP91, and WP911		WPR and WP24			WP91 WP92 WP911
					Longi-tudinal	Trans-verse	Longi-tudinal	Trans-verse		Longi-tudinal	Trans-verse
Elongation:
Standard round specimen, or small proportional specimen, min % in 4 D					22.00	14.00	20.00			20.00	13.00
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]					30.00	20.00	28.00
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)					B	B	B

A WPB and WPC fittings manufactured from plate shall have a minimum elongation of 17 %. B For each 1⁄32 in. [0.79 mm] decrease in wall thickness below 5⁄16 in. [7.94 mm], a deduction of 1.5 % for longitudinal and 1.0 % for transverse from the values shown above is permitted. The following table gives the minimum value for various wall thicknesses.

Wall Thickness				Grades
				All Grades except WPR, WP91 and WP911		WPR	WP91, WP92, and WP911
	in.	[mm]	Longitudinal	Transverse	Longitudinal	Longitudinal
5⁄16	(0.31)	7.94	30.00	20.00	28.00	20.00
9⁄32	(0.28)	7.14	28.50	19.00	26.50	19.00
1⁄4	(0.25)	6.35	27.00	18.00	25.00	18.00
7⁄32	(0.22)	5.56	25.50		23.50	17.00
3⁄16	(0.19)	4.76	24.00		22.00	16.00
5⁄32	(0.16)	3.97	22.50		20.50	15.00
1⁄8	(0.13)	3.17	21.00		19.00	14.00
3⁄32	(0.09)	2.38	19.50		17.50	13.00
1⁄16	(0.06)	1.59	18.00		16.00	12.00

1.1This specification2 covers wrought carbon steel and alloy steel fittings of seamless and welded construction covered by the latest revision of ASME B16.9, B16.11, MSS-SP-79, MSS-SP-83, MSS-SP-95, and MSS-SP-97. These fittings are for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures. Fittings differ-ing from these ASME and MSS standards shall be furnished in accordance with Supplementary Requirement S58 of Specifi-cation A960/A960M.
1.2Optional supplementary requirements are provided for fittings where a greater degree of examination is desired. When desired, one or more of these supplementary requirements may be specified in the order.
1.3This specification does not cover cast welding fittings or fittings machined from castings. Cast steel welding fittings are governed by Specifications A216/A216M and A217/A217M.