ASTM A234 WPB is the Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service.

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Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service

Abstract …

Chemical Composition (%) of ASTM A234/A234M fittings

Grade	Type	Chemical Composition (%)
		C	Si	S	P	Mn	Cr	Ni	Mo	Other	ób	ós	δ5
WPB	0.3	0.1min	0.058	0.05	0.29-1.06	0.4	0.4	0.15	V:0.06;Nb:0.02	415-585	240	22	197
WPC	0.35	0.1min	0.058	0.05	0.29-1.06	0.4	0.4	0.15	V:0.06;Nb:0.02	485-655	275	22	197
WP1	0.28	0.1-0.5	0.045	0.045	0.3-0.9			0.44-0.65		380-550	205	22	197
WP12 CL1	0.05-0.2	0.6	0.045	0.045	0.3-0.8	0.8-1.25		0.44-0.65		415-585	220	22	197
WP12 CL2	0.05-0.2	0.6	0.045	0.045	0.3-0.8	0.8-1.25		0.44-0.65		485-655	275	22	197
WP11 CL1	0.05-0.15	0.5-1	0.03	0.03	0.3-0.6	1-1.5		0.44-0.65		415-585	205	22	197
WP11 CL2	0.05-0.2	0.5-1	0.04	0.04	0.3-0.8	1-1.5		0.44-0.65		485-655	275	22	197
WP11 CL3	0.05-0.2	0.5-1	0.04	0.04	0.3-0.8	1-1.5		0.44-0.65		520-690	310	22	197
WP22 CL1	0.05-0.15	0.5	0.04	0.04	0.3-0.6	1.9-2.6		0.87-1.13		415-585	205	22	197
WP22 CL3	0.05-0.15	0.5	0.04	0.04	0.3-0.6	1.9-2.6		0.87-1.13		520-690	310	22	197
WP5 CL1	0.15	0.5	0.03	0.04	0.3-0.6	4-6		0.44-0.65		415-585	205	22	217
WP5 CL3	0.15	0.5	0.03	0.04	0.3-0.6	4-6		0.44-0.65		520-690	310	22	217
WP9 CL1	0.15	1	0.03	0.03	0.3-0.6	8-10		0.9-1.1		415-585	205	22	217
WP9 CL3	0.15	1	0.03	0.03	0.3-0.6	8-10		0.9-1.1		520-690	310	22	217
WPR	0.2		0.05	0.045	0.4-1.06		1.6-2.24			435-605	315	22/28	217
WP91	0.08-0.12	0.2-0.5	0.01	0.02	0.3-0.6	8-9.5	0.4	0.85-1.05	See sdandard	585-760	415	20	248
WP911	0.09-0.13	0.1-0.5	0.01	0.02	0.3-0.6	8.5-10.5	0.4	0.9-1.1	See sdandard	620-840	440	20	248

Notes:

Mechanical properties of ASTM A234

Tensile Requirements	WPB	WPC, WP11CL2	WP11CL1	WP11CL3
Tensile Strength, min, ksi[MPa]	60-85	70-95	60-85	75-100
(0.2% offset or 0.5% extension-under-load)	[415-585]	[485-655]	[415-585]	[520-690]
Yield Strength, min, ksi[MPa]	32	40	30	45
	[240]	[275]	[205]	[310]

What is the manufacturing process of ASTM A234 WPB pipe fittings?

In very large sizes, the fittings may be manufactured in pieces and welded together as is the case for many large fittings.

The term used for the manufacturing is called “wrought” which means it is worked as opposed to being cast or forged.

As to the W standing for weldable, I’m not sure that is correct since that are many, many pipe fittings that are weldable but carry designations other than a W. Note the reference below.

Forging is the manufacturing process of ASTM A234 WPB pipe fittings.

ASTM A234/A234M-07

Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
This standard covers wrought carbon steel fittings of seamless and welded construction which are manufactured to the dimensional specifications of ASME B16.9 and B16.28. These fittings are primarily for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures.

Referenced Documents

ASTM Standards

High-Temperature Service

ASME Standards

 This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction. These fittings are for use in pressure piping and in pressure vessel fabrication for service at moderate and elevated temperatures. The material for fittings shall consist of killed steel, forgings, bars, plates, seamless or fusion-welded tubular products with filler metal added. Forging or shaping operations may be performed by hammering, pressing, piercing, extruding, upsetting, rolling, bending, fusion welding, machining, or by a combination of two or more of these operations. The forming procedure shall be so applied that it will not produce injurious imperfections in the fittings. Fittings, after forming at an elevated temperature, shall be cooled to a temperature below the critical range under suitable conditions to prevent injurious defects caused by too rapid cooling, but in no case more rapidly than the cooling rate in still air. The fittings shall be subjected to tension test, hardness test, and hydrostatic test.

• For each reduction of 0.01% below the specified C maximum, an increase of 0.06% Mn above the specified maximum will be permitted, up to a maximum of 1.35%.
• The sum of Cu, Ni, Cr, and Mo shall not exceed 1.00%.
• The sum of Cr and Mo shall not exceed 0.32%.
• The maximum carbon equivalent (C.E.) shall be 0.50, based on heat analysis and the formula C.E.=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15.

The WPB is not short hand for any process. It is simply an identifier developed by ASTM. The fittings in question are manufactured in the same manner as the companion pipe for this specification.

• W = WELDABLE / wrought
• P = RELATED TO P NUMBER OF ALLOY MATERIAL
• B = REFER TO MINIMUM YIELD OF MATERIAL

• A216/A216M Specification for Steel Castings, Carbon, Suitable for Fusion Welding, for High-Temperature Service
• A217/A217M Specification for Steel Castings, Martensitic Stainless and Alloy, for Pressure-Containing Parts, Suitable for

• A960/A960M Specification for Common Requirements for Wrought Steel Piping Fittings

• B16.11 Forged Steel Fittings, Socket Welding and Threaded
• ASME Boiler and Pressure Vessel Code
• SectionIX Welding Qualifications