What Is ASTM A234 WPB?
ASTM A234 is the specification for wrought carbon steel and alloy steel fittings for moderate- and high-temperature service. Grade WPB (wrought piping, grade B) is the standard carbon steel buttwelding fitting material used with ASME B16.9 elbows, tees, reducers, caps and stub ends.
Temperature Range
WPB fittings are rated -29°C to 425°C, matching the carbon-steel pressure-temperature basis already documented on our ASME B16.9 fittings page.
Material Group (per ASME B16.5)
As a carbon steel of the same family as A105/A350 LF2, WPB fittings pair with Group 1.1 flanges in ASME B16.5 piping systems.
Corrosion Resistance
Carbon steel behavior per the Schweitzer tables (Part A, Carbon Steel row): good in neutral, alkaline and dry service; not recommended in acids or corrosive aqueous media. Coat or paint exposed fittings.
Typical Applications
- ASME B16.9 buttwelding elbows, tees, reducers and caps, NPS 1/2–48
- Oil, gas, water and steam process piping
- Piping matched to A105 flanges and A106/A53 pipe
Chemistry & Mechanical Properties
Composition and mechanical properties per ASTM A234 — consult the standard for exact limits. 3.1 mill certificates supplied.
Related Standards
- ASME B16.9 — Buttwelding Fittings (NPS 1/2–48)
- ASME B16.5 — Pipe Flanges
- ASME B16.11 — Forged Fittings
- ASTM A105 — Carbon Steel Flanges
- ASTM A420 WPL6 — Low-Temperature Fittings
- Buttwelding Elbows
- Equal Tees
FAQ
What temperature range does WPB cover?
-29°C to 425°C, the carbon-steel basis of the ASME B16.9/B16.5 tables.
What sizes of WPB fittings are available?
ASME B16.9 buttwelding fittings from NPS 1/2 through NPS 48 (elbows, tees, reducers, caps, stub ends).
Is WPB suitable for low temperature?
For low-temperature service use ASTM A420 WPL6 fittings, which are notch-toughness tested.
WPB or WPC?
WPC is a higher-strength carbon grade; WPB is the standard all-purpose choice — confirm with your piping specification.
Can WPB fittings carry steam service?
Yes — the carbon-steel range of -29°C to 425°C covers typical saturated and moderate-temperature steam piping.
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