ASTM A234 WP5 Pipe Fittings refers to wrought alloy steel pipe fittings made from Grade WP5 material, designed for use in high-temperature and high-pressure environments like refineries, power plants, and chemical processing.
ASTM A234 WP5 pipe fittings are made from a low-alloy steel known as Grade 5. The main elements in the composition of this steel include chromium (Cr), which provides excellent corrosion resistance and high-temperature strength, and molybdenum (Mo), which enhances the material’s overall strength and resistance to creep.
What is A234 WP5 material?
A234 WP5 is a grade of alloy steel used primarily for butt-weld pipe fittings such as elbows, tees, reducers, and caps in high-temperature and high-pressure applications.
Breakdown of the Designation
ASTM A234: The standard specification for wrought carbon steel and alloy steel pipe fittings.
WP: “Wrought Pipe” — indicates the fitting is made from wrought material (not cast).
5: Refers to the alloy steel grade, specifically Chrome-Moly alloy steel with approximately 5% chromium and 0.5% molybdenum .
Applications
Power plants
Petrochemical plants
Refineries
Boiler and pressure vessel applications
Superheater and reheater tubes
What is the ASTM A234 specification?
| Size Range | 1/2″ – 80″ / DN15 – 2000 |
| Thickness Schedule | SCH 10 – SCH 160, XXS |
| Standard | GB/T12459, GB/T13401, HG/T21635/21631, SH3408/3409， ANSI / ASME B16.9, MSS SP 43, JIS B2311/2312/2313, DIN2605/2615/2616/2617, EN10253 |
| Carbon Steel | Q235, 20#, 35#, 45#, 20G,Q345B, 16Mn, ASTM A234 WPB/WPC, A420 WPL6 |
| Alloy Steel | ASTM A234 WP11 / WP12 / WP 5 / WP9 / WP91 / WP92,15CrMoG, 12Cr1MoVG, 12Cr5Mo, 1Cr5Mo, Cr9Mo, 10CrMo910, 12CrMo4-5 |
Scope
This specification 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 differing from these ASME and MSS standards shall be furnished in accordance with Supplementary Requirement S58 of Specification A960/A960M.
Heat Treatment
Heat Treatment Procedures—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. Heat treatment temperatures specified are metal (part) temperatures.
Materials and Manufacturing
The raw material for making ASTM A234 fittings hall be fully killed, consisting of forgings, bars, plates, sheet, and seamless or fusion-welded pipe products with filler metal added and shall conform to the chemical requirements of Table 1. Unless specified for carbon steel plates or sheet, the steel may be made to either coarse grain or fine grain practice. Which ASTM A234 WP9 shall be made to fine grain practice.
Forgings or forming operations could be perfomred by hammering, pressing, piercing, upseting, rolling, extruding, bending, fusion welding, machining, or by a combination of two or more above operations. Which the point of manufacturing is not to produce injurious imperfections in the fittings.
Alloy Steel WP5 Butt Weld Fittings Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Cr | Mo |
| ASTM A234 WP5 CL1,CL3 | MIN | 0.30 | 4.00 | 0.440 | ||||
| MAX | 0.150 | 0.60 | 0.040 | 0.030 | 0.50 | 6.00 | 0.650 |
Alloy Steel WP5 Butt Weld Fittings Mechanical Properties
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % |
| ASTM A234 WP5 CL1 | 415min | 205min | 30min |
| ASTM A234 WP5 CL3 | 520min | 310min | 30min |
WPB, WPC, and WPR Fittings:
Hot-formed WPB, WPC, and WPR fittings upon which the final forming operation is completed at a temperature above 1150 °F [620 °C] and below 1800 °F [980 °C] need not be heat treated provided they are cooled in still air.
Hot-formed or forged WPB, WPC, and WPR fittings finished at temperature in excess of 1800 °F [980 °C] shall subsequently be annealed, normalized, or normalized and tempered. Hot-forged fittings NPS 4 or smaller need not be heat treated.
WPB, WPC, and WPR fittings over NPS 12, produced by locally heating a portion of the fitting stock to any temperature for forming, shall be subsequently annealed, normalized, or normalized and tempered. Fittings such as elbows, tees, header tees, reducers and lap joint stub ends with a carbon content less than 0.26 %, NPS 12 and under, shall not require heat treatment after forming a locally heated portion of the fitting.
Cold-formed WPB, WPC, and WPR fittings, upon which the final forming operation is completed at a temperature below 1150 °F [620 °C], shall be normalized, or shall be stress relieved at 1100 to 1275 °F [595 to 690 °C].
WPB, WPC, and WPR fittings produced by fusion welding and having a nominal wall thickness at the welded joint of 3 ⁄4 in. [19 mm] or greater shall be post-weld heat treated at 1100 to 1250 °F [595 to 675 °C].
At the option of the manufacturer, WPB and WPC fittings produced by any of the methods in Section 67 may be annealed, normalized, or normalized and tempered.
Butt Weld Pipe Fittings Tolerance
| Tolerances | ||||||||||||||
| All Fittings [Notes(1)and (2) | Center to-End Dimensions of 90 deg and 45 deg Elbows and Tees A.B,C,M | Overall Length of Reducers and Lap Joint Stub Ends E,H | Overall Length of Caps, E | 180 deg Returns | Lap Joint Ends [Note (6) | Angularity Tolerances | ||||||||
| Nominal PipeSize (NPS) | Outside Diameter at Bevel, D [Notes (3) and (4) | Inside Diameter at End [Notes (3) and (5)] | Center-to-Center Dimension 0 | Back- to-face Dimen- sion K | Align- ment of Ends U | Outside Diameter of Lap G | Fllet Radius of Lap R | Lap Thick- ness, T | Nominal Pipe Size (NPS) | Off Angle Q | Off Plane, p | |||
| 1/2% to2 1/2 % | +0.06, -0.03 | 0.03 | 0.06 | 0.06 | 0.12 | 0.25 | 0.25 | 0.03 | +0, -0.03 | +0, -0.03 | +0.06, -0 | 1/2%to 4 | 0.03 | 0.06 |
| 3 to 3 1/2% | 0.06 | 0.06 | 0.06 | 0.06 | 0.12 | 0.25 | 0.25 | 0.03 | +0, -0.03 | +0, -0.03 | +0.06 -0 | 5 to 8 | 0.06 | 0.12 |
| 4 | 0.06 | 0.06 | 0.06 | 0.06 | 0.12 | 0.25 | 0.25 | 0.03 | +0, -0.03 | +0, -0.06 | +0.06, -0 | 10 to 12 | 0.09 | 0.19 |
| 5 to 8 | +0.09, -0.06 | 0.06 | 0.06 | 0.06 | 0.25 | 0.25 | 0.25 | 0.03 | +0, -0.03 | +0, -0.06 | +0.06 -0 | 14 to 16 | 0.09 | 0.25 |
| 10 to 18 | +0.16, -0.12 | 0.12 | 0.09 | 0.09 | 0.25 | 0.38 | 0.25 | 0.06 | +0, -0.06 | +0, -0.06 | +0.12, -0 | 18 to 24 | 0.12 | 0.38 |
| 20 to24 | +0.25, -0.19 | 0.19 | 0.09 | 0.09 | 0.25 | 0.38 | 0.25 | 0.06 | +0, -0.06 | +0, -0.06 | +0.12, -0 | 26 to 30 | 0.19 | 0.38 |
| 26 to 30 | +0.25, -0.19 | 0.19 | 0.12 | 0.19 | 0.38 | 32 to 42 | 0.19 | 0.50 | ||||||
| 32 to 48 | +0.25, -0.19 | 0.19 | 0.19 | 0.19 | 0.38 | 44 to 48 | 0.19 | 0.75 | ||||||
Types of Alloy Steel Butt Weld Pipe Fittings
There are various types of butt weld pipe fittings, such as elbows, tees, crosses, reducers, etc. These different types of butt weld pipe fittings each play an important role in the pipeline system.
Elbow: Elbow is a pipe fitting that changes the flow direction of the pipeline.
Tee: Tee is used for branch connection of pipeline. The main function of the tee is to change the direction of the fluid.
Cross: Cross is a pipe fitting with four ports, which can divide a main pipeline into three branch pipelines, or merge three branch pipelines into one main pipeline.
Reducer: Reducer is mainly used to connect two pipes of different diameters. Reducers are mainly divided into concentric reducers and eccentric reducers.
Cap: A cap is a type of pipe fitting used to terminate the end of a piping system or seal off a pipe section. It’s welded onto the pipe, creating a permanent closure that can handle internal pressure and fluid flow.
What is the difference between ASTM A420 and A234?
- Temperature Service
| Standard | Temperature Range |
| ASTM A234 | High-temperature service (up to 600°C or 1112°F) |
| ASTM A420 | Low-temperature service (as low as -50°C or -58°F and below) |
- Material Types
| Standard | Base Material Types |
| A234 | Carbon steel and alloy steel for high-temp and pressure systems |
| A420 | Carbon steel and low-alloy steel specifically for low-temp applications |
- Common Grades
| Standard | Common Grades |
| A234 | WPB, WPC (carbon steel), WP1, WP5, WP11, WP22 (alloy steels) |
| A420 | WPL6 (most common), WPL3, WPL8 (low-temp carbon steels) |
- Typical Applications
| Standard | Used In |
| A234 | Power plants, oil & gas, refineries, chemical plants |
| A420 | Cryogenic systems, LNG plants, cold weather pipelines |
- Impact Testing
ASTM A420 requires mandatory impact testing to ensure toughness at low temperatures.
ASTM A234 may not require impact testing unless specified for certain alloy grades or service conditions.
What is the difference of material WP5,WP9,WP11,WP22?
WP5, WP9, WP11, and WP22 are all grades under ASTM A234, which covers wrought alloy steel pipe fittings used for high-temperature service.
The main differences between these grades are in their chemical composition, which affects their temperature resistance, strength, and creep resistance (resistance to long-term deformation under high temps).
Quick Summary Table
| Grade | Cr (%) | Mo (%) | Temp Resistance | Key Feature |
| WP5 | 4-6 | 0.44-0.65 | High | Good general high-temp strength |
| WP9 | 8-10 | 0.9-1.1 | Very High | Higher strength & creep resistance than WP5 |
| WP11 | 1-1.5 | 0.44-0.654 | Moderate–High | Common in power piping; good weldability |
| WP22 | 1.9-2.6 | 0.87-1.13 | High | Stronger than WP11; better at higher temps |
Detailed Breakdown
✅ WP5 (5Cr-0.5Mo)
Good high-temperature strength
Used in steam lines, reformers, and heat exchangers
Comparable to ASTM A335 P5 pipe material
✅ WP9 (9Cr-1Mo)
Excellent high-temp and pressure resistance
Strong creep resistance → used in ultra-supercritical boilers
Comparable to A335 P9 pipe
More expensive but more durable at very high temps
✅ WP11 (1.25Cr-0.5Mo)
One of the most widely used in power piping systems
Good weldability and decent high-temp properties
Less expensive than WP5/WP9
Common in steam headers, boiler tubes, and super-heaters
✅ WP22 (2.25Cr-1Mo)
Higher strength and temp resistance than WP11
Good for high-pressure steam and hot hydrogen environments
Popular in refineries and thermal power plants
Applications Overview
| Application Type | Suitable Grades |
| Medium pressure steam piping | WP11 |
| High pressure boilers | WP22, WP9 |
| Refineries | WP5, WP22 |
| Supercritical steam systems | WP9 |
Advantages
✅ 1. Excellent High-Temperature Strength
✅ 2. Good Creep Resistance
✅ 3. Corrosion and Oxidation Resistance
✅ 4. Compatibility with Alloy Steel Piping (like ASTM A335 P5)
✅ 5. Strong Weldability (Post-Weld Heat Treatable)
✅ 6. Pressure Retention and Safety
✅ 7. Long Service Life & Cost-Efficiency
Common WP5 Applications in Petrochemical Plants
High-pressure steam and hydrogen lines
Reactor feed piping
Reformers and catalytic units
Heat exchanger headers
Hot hydrocarbon and gas lines
You can get an offer for products in below material forms:
-Pipe and Tube (EN 10216-5, ASTM A213, ASTM A249, A312, A790,)
-Forged Fitting and Flange (ASTM A182 , ASTM A105,ASTM B564 )
-Butt Weld Fittings (ASTM A234, ASTM A403,ASTM A815)
-Round bar , Billet (ASTM A276, ASTM A479)
– Plate, Sheet, Strip(ASTM A240, EN 10028-7, A480)
-Bolting, Nuts（ASTM A193, A194, A320）
ASTM A234 WP5 Pipe Fittings Exported Countries
We Export ASTM A234 WP5 Pipe Fittings to Saudi Arabia, United Arab Emirates, Qatar, Bahrain, Oman, Kuwait, Turkey, Egypt, Yemen , Syria, Jordan, Cyprus, Singapore, Malaysia, Indonesia, Thailand, Vietnam, South Korea, Japan, Sri Lanka, Maldives, Bangladesh, Cambodia, Argentina, Bolivia, Brazil, Venezuela, Colombia, Ecuador, Guyana, Paraguay, Uruguay, United States Of America, Canada, Mexico, Panama, Jamaica, Bahamas, Denmark, Norway, Germany, France,Italy, United Kingdom, Spain, Belgium, Greece, Czech Republic, Portugal, Hungary, Albania, Austria, Finland, Ireland, Croatia, Malta, Nigeria, Algeria, Angola, South Africa, Libya, Egypt, Sudan, Europe, Africa, Asia, North America, South America, Middle East.etc