ASTM A234 Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel 

ASTM A234 Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel

ASTM A234 is the standard specification for wrought carbon steel and alloy steel pipe fittings used in moderate and high-temperature pressure piping systems.
This page provides an overview of ASTM A234 materials and offers a downloadable PDF specification .

What is ASTM A234?

ASTM A234 covers butt-welded pipe fittings such as:

  • Elbows (45°, 90°, 180°)

  • Tees (Equal & Reducing)

  • Reducers (Concentric & Eccentric)

  • Caps

  • Crosses

These fittings are designed for pressure piping and pressure vessel service at ambient and elevated temperatures.

ASTM A234 Grades

ASTM A234 includes both carbon steel and alloy steel grades:

Carbon Steel Grade

  • WPB – General pressure & temperature service

Alloy Steel Grades

 

  • WP1

  • WP11 – 1.25Cr-0.5Mo

  • WP22 – 2.25Cr-1Mo

  • WP5 – 5Cr-0.5Mo

  • WP9 – 9Cr-1Mo

  • WP91 – 9Cr-1Mo-V-Nb (advanced creep-resistant steel)

Each grade is selected based on operating temperature, pressure, and creep resistance requirements.

Chemical Composition (Typical)

Grade and Marking Symbol Carbon Manganese Phosphorus Sulfur Silicon Chromium Molybdenum Nickel Copper Others
WPB B,C,D,E 0.30 0.29–1.06 0.050 0.058 0.10 min 0.40 0.15 max 0.40 0.40 Vanadium 0.08
WPC C,D,E 0.35 0.29–1.06 0.050 0.058 0.10 min 0.40 0.15 max 0.40 0.40 Vanadium 0.08
WP1 0.28 0.30–0.90 0.045 0.045 0.10–0.50 … 0.44–0.65 … …
WP12 CL1 0.05–0.20 0.30–0.80 0.045 0.045 0.60 0.80–1.25 0.44–0.65 … …
WP12 CL2
WP11 CL1 0.05–0.15 0.30–0.60 0.030 0.030 0.50–1.00 1.00–1.50 0.44–0.65 … …
WP11 CL2 0.05–0.20 0.30–0.80 0.040 0.040 0.50–1.00 1.00–1.50 0.44–0.65 … …
WP11 CL3
WP22 CL1 0.05–0.15 0.30–0.60 0.040 0.040 0.50 1.90–2.60 0.87–1.13 … …
WP22 CL3
WP5 CL1 0.15 0.30–0.60 0.040 0.030 0.50 4.0–6.0 0.44–0.65 … …
WP5 CL3
WP9 CL1 0.15 0.30–0.60 0.030 0.030 1.00 8.0–10.0 0.90–1.10 … …
WP9 CL3
WP91 Type 1 0.08–0.12 0.30–0.60 0.020 0.010 0.20–0.50 8.0–9.5 0.85–1.05 0.40 … V 0.18–0.25; Cb 0.06–0.10; N 0.03–0.07; Al 0.02; Ti 0.01
WP91 Type 2 0.08–0.12 0.30–0.50 0.020 0.005 0.20–0.40 8.0–9.5 0.85–1.05 0.20 0.10 V 0.18–0.25; Cb 0.06–0.10; N 0.035–0.070; Al 0.020; N/Al ≥4.0; B 0.001
WP92 0.07–0.13 0.30–0.60 0.020 0.010 0.50 8.50–9.50 0.30–0.60 0.40 … B 0.001–0.006; Cb 0.04–0.09; N 0.030–0.070; Ti 0.01; W 1.50–2.00; V 0.15–0.25; Zr 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 Types 1 and 2 WP92 / WP911 WP115 WP12 CL1
Tensile strength, minimum unless a range is given ksi [MPa] 60 [415] 70 [485] 55–80 [380–550] 60 [415] 63–88 [435–605] 75 [520] 85 [585] 90 [620] 90–120 [620–840] 90 [620] 60 [415]
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] 65 [450] 32 [220]

 

Heat Treatment Requirements

ASTM A234 fittings are supplied with mandatory heat treatment:

Grade Heat Treatment
WPB Normalized / Stress Relieved
WP11 Normalized & Tempered
WP22 Normalized & Tempered
WP5 Annealed or Normalized & Tempered
WP9 Normalized & Tempered
WP91 Normalized + Tempered (Controlled)

Hardness Limits

  • WPB: ≤ 197 HB

  • WP11 / WP22: ≤ 235 HB

  • WP91: ≤ 250 HB

Testing & Inspection

ASTM A234 fittings are supplied with:

  • Chemical composition analysis

  • Mechanical testing

  • Heat treatment verification

  • Dimensional inspection

  • Visual & surface inspection

  • EN 10204 3.1 Mill Test Certificate

Size Range

  • Nominal Pipe Size (NPS): ½″ – 48″

  • Wall Thickness: SCH 10 – SCH XXS

  • Manufacturing: Seamless / Welded (as applicable)

Download ASTM A234 PDF Standard Specification

📄 ASTM A234 Alloy Steel Pipe Fittings – Technical PDF Datasheet

✔ Chemical composition
✔ Mechanical properties
✔ Heat treatment requirements
✔ Hardness limits
✔ Testing & inspection
✔ Grade comparison

👉 [Download ASTM A234/234M 24 standard latest edition PDF]

👉 [Download ASME SA234/234M  standard latest edition PDF]

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