ASTM A234/A234M – 2024 refers to the latest version (2024) of the ASTM A234/A234M specification, which covers wrought carbon steel and alloy steel fittings.
These fittings are of seamless and welded construction, and they are primarily used for moderate and high-temperature service in pressure piping systems. The specification applies to various types of fittings, such as elbows, reducers, tees, and caps, which are typically made according to standards like ASME B16.9 and MSS-SP-79.
Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction, adhering to the latest revisions of ASME B16.9, B16.11, MSS-SP-79, MSS-SP-83, MSS-SP-95, and MSS-SP-97. These fittings are intended for service at moderate and elevated temperatures. Fittings differing from these ASME and MSS standards shall be furnished in accordance with supplementary requirement S58 of Specification A960/A960M.
Optional supplementary requirements are provided for fittings where a greater degree of examination is desired. When applicable, these requirements must be specified in the order.
The starting material for fittings shall be killed steel, consisting of forgings, bars, plates, sheets, and seamless or fusion-welded tubular products with filler metal added, and it shall conform to the chemical requirements of Table 1. Unless otherwise specified for carbon steel plates and sheets, the steel may be produced using either coarse grain or fine grain practice. Grade WP9 shall be made using fine grain practice.
A starting material specification that specifically requires the addition of any element beyond those listed for the applicable grade of material in Table 1 is not permitted. However, this does not exclude the use of deoxidizers or the judicious use of elements for grain size control.
A234/A234M -24 Chemical Requirement
- Note 1- All requirements are maximum unless otherwise indicated.
- Note 2- Where an ellipsis (…) appears in this table, there is no requirement and analysis for the element need not be determined or reported
| Grade and Marking Symbol | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Molybdenum | Nickel | Copper | Others |
| WPB【B,C,D,E】 | 0.3 | 0.29–1.06 | 0.05 | 0.058 | 0.10 min | 0.4 | 0.15 max | 0.4 | 0.4 | Vanadium 0.08 |
| WPC【C,D,E】 | 0.35 | 0.29–1.06 | 0.05 | 0.058 | 0.10 min | 0.4 | 0.15 max | 0.4 | 0.4 | Vanadium 0.08 |
| WP1 | 0.28 | 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 | 0.6 | 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 | 0.5 | 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 | 0.30–0.60 | 0.04 | 0.03 | 0.5 | 4.0–6.0 | 0.44–0.65 | … | … | … |
| WPR | 0.2 | 0.40–1.06 | 0.045 | 0.05 | … | … | … | 1.60–2.24 | 0.75–1.25 | |
| WP91 Type 1 | 0.08–0.12 | 0.30–0.60 | 0.02 | 0.01 | 0.20–0.50 | 8.0–9.5 | 0.85–1.05 | 0.4 | … | Vanadium 0.18–0.25 Columbium 【G】 0.06–0.10 Nitrogen 0.03–0.07 Aluminum 0.02 【F】 Titanium 0.01 【F】 |
| WP91 Type 2 | 0.08–0.12 | 0.30–0.50 【F】 | 0.020 【F】 | 0.005 【F】 | 0.20–0.40 | 8.0–9.5 【F】 | 0.85–1.05 | 0.20【 F】 | 0.10 【F】 | Vanadium 0.18-0.25 Columbium 【】0.06-0.10 Nitrogen 0.035-0.070【F】 Aluminum 0.020【F】 N/Al ratio ≥4.0 Boron0.001【F】 Zirconium 0.01【F】 Titanium 0.01【F】 Arsenic 0.010【F】 Tin 0.010【F】 Antimony 0.003【F】 Tungsten 0.05【F】 |
| WP115 | 0.08–0.13 | 0.20–0.50 | 0.02 | 0.005 | 0.15–0.45 | 10.0–11.0 | 0.40–0.60 | 0.25 | 0.1 | Vanadium 0.18-0.25 Niobium 0.02-0.06 Nitrogen 0.030-0.070 Aluminum 0.02 Titanium 0.01 Boron 0.001 Zirconium 0.01 Tungsten 0.05 Arsenic 0.010 Tin0.010 Antimony 0.003 N/AI ratio 4.0 min CNB【H】10.5 |
| 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 | 0.4 | … | Vanadium 0.18-0.25 Columbium 【G】 0.060-0.10 Nitrogen 0.04-0.09 Aluminum 0.02 max 【F】 Boron 0.0003-0.006 Tungsten 0.90-1.10 Titanium 0.01 max 【F】 Zirconium 0.01 max 【F】 |
| WP92 | 0.07–0.13 | 0.30–0.60 | 0.02 | 0.01 | 0.5 | 8.5–9.5 | 0.30–0.60 | 0.4 | … | Aluminum 0.02 【F】 Boron 0.001-0.006 Columbium 【G】 0.04-0.09 Nitrogen 0.030-0.070 Titanium 0.01【F】 Tungsten 1.50-2.00 Vanadium 0.15-0.25 Zirconium 0.01 【F】 |
【A】When fittings are of welded construction, the grade and marking symbol shown above shall be supplemented by the letter “w”
【B】Fittings made from bar or plate may have 0.35 max carbon.
【C】Fittings made from forgings may have 0.35 max carbon and 0.35 max silicon with no minimum.
【D】 For each reduction of 0.01 % below the specified carbon maximum, an increase of 0.06 % manganese above the specified maximum will be permitted, up to a maximum of 1.65 %.
【E】 The sum of Copper, Nickel, Chromium, and Molybdenum shall not exceed 1.o0 %.
【F】Applies both to heat and product analyses.
【G】Columbium (Cb) and Niobium (Nb) are alternate names for element 41 in the Periodic Table of the Elements.
【H】Chromium Nickel Balance is defined as CNB = (Cr + 6Si + 4Mo + 1.5W + 11V + 5Nb + 9Ti + 12AI) (40C + 30N + 4Ni + 2Mn + 1Cu)
A234/A234M -24 Tensile Requirements
| 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 1and 2 | WP92 WP911 | WP115 | WP12 CL1 |
| Tensile strength, minimum unless a range is given ksi [MPa] | 60 [415] | 60 [415] | 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-loed) | 35 [240] | 35 [240] | 30 [205] | 30 [205] | 46 [315] | 45 [310] | 60 [415] | 60 [415] | 64 [440] | 65 [450] | 32 [220] |
| Elongation: | Elongation Requirerments | |||||
| Grades | ||||||
| All Grades except WPR, WPg1 Type 1 and Type 2, WP115 and WP911 | WPR and WP24 | WP 91 Types 1 and 2, WP92, WP115, WP 911 | ||||
| Longitudinal | Transverse | Longitudinal | Transverse | Longitudinal | Transverse | |
Standard round specimen, or small proportional specimen, min % in 4 D | 22 | 14 | 20 | … | 20 | 13 |
| Strip specimen for wall thinkness 3/16 in.[7.94mm] and over, and for all small sizes tested in full section; min % in 2 in. [50 mim] | 30 | 20【A】 | 28 | … | … | … |
| Formula for calculating minimum elongaition for strip specimens thinner than 3/16 in.[7.94mm]; min % in 2 in. [50 mm] (1/2-in. [12.7mm] wide specimen) t= actual thickness in inches t= actual thickness in mm | 48t+15 1.9t+15 | 32t+10 1.26t+10 | 48t+13 1.9t+13 | … | 32t+10 1.26t+10 | … |
【A】 WPB and WPC fitings manufactured from plate shall have a minimum elongation of 17 %,
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