ASTM A234 WPB Eccentric Reducer
An eccentric reducer is a pipe fitting used to join two pipes of different diameters with an offset centerline, maintaining the pipe's bottom or top alignment. Unlike concentric reducers, eccentric reducers prevent air or gas pockets in horizontal pipelines, ensuring smooth liquid flow and preventing cavitation.
ASTM A234 WPB specifies carbon steel forged and welded fittings suitable for pressure piping applications, providing a balance of mechanical strength, corrosion resistance, and ease of fabrication.
ASTM A234 WPB Eccentric Reducer Specification
| Item | Details |
| Material Standard | ASTM A234 Grade WPB |
| Dimensional Standard | ASME B16.9 (Buttwelding Fittings), MSS-SP-75 |
| Product Type | Eccentric Reducer |
| Size Range | 1/2" - 48" (DN15 - DN1200) |
| Wall Thickness | Sch 20, Sch 40, STD, Sch 80, XS, Sch 160, XXS |
| Manufacturing Process | Pressing, Forging, Machining |
| Connection Type | Butt Welding (BW) |
| Applications | Petroleum, Chemical, Power, Natural Gas, Shipbuilding, Water Treatment |
ASTM A234 WPB Eccentric Reducer Chemical Composition and Mechanical Properties (ASME B16.9 / ASTM A234)
Chemical Composition (%)
| C (max) | Mn | P (max) | S (max) | Si (min) | Cr/Mo/Ni/Cu (max) |
| 0.30 | 0.29 - 1.06 | 0.050 | 0.058 | 0.10 | Total ≤ 1.00 |
Mechanical Properties
| Property | Required Value |
| Tensile Strength | ≥ 415 MPa (60,000 psi) |
| Yield Strength | ≥ 240 MPa (35,000 psi) |
| Elongation | Per standard formula calculation (Typically ≥ 20% - 30%) |
| Hardness | ≤ 197 HBW |
ASTM A234 WPB Eccentric Reducer Dimensions (Dimensions per ASME B16.9)
The key dimensions of an eccentric reducer include the Large End Outer Diameter (D), Small End Outer Diameter (d), and the End-to-End Length (H).
| Nominal Pipe Size (NPS) | Large End OD D (mm) | Small End OD d (mm) | Length H (mm) |
| 2" x 1-1/2" | 60.3 | 48.3 | 76 |
| 4" x 3" | 114.3 | 88.9 | 102 |
| 6" x 4" | 168.3 | 114.3 | 133 |
| 8" x 6" | 219.1 | 168.3 | 152 |
| 12" x 10" | 323.8 | 273.1 | 203 |
| 24" x 20" | 609.6 | 508.0 | 508 |
Custom sizes and wall thicknesses available upon request.
ASTM A234 WPB Eccentric Reducer Surface Treatment
To prevent rusting during transportation and storage, carbon steel reducers are typically treated with the following methods:
Black Painting / Varnish: The most common method used for temporary rust prevention.
Anti-rust Oil: Lightweight protection that is easy to clean before installation.
Hot Dip Galvanized: Used for extremely humid or high-corrosion environments.
3LPE / FBE Coating: Specialized coatings for underground piping networks.
Shot Blasting: Removes mill scale to create a smooth surface, ideal for subsequent coating or painting.
ASTM A234 WPB Eccentric Reducer Temperature Rating
ASTM A234 WPB is specifically designed for moderate and high-temperature services.
Recommended Temperature Range:
−29∘C(−20∘F) to 425∘C(800∘F).
Important Considerations:
When used for prolonged periods at temperatures above 425°C, the carbides in carbon steel may convert to graphite, which can lead to a significant decrease in strength.
If lower temperatures are required (Low-Temperature Service), ASTM A420 WPL6 should be selected.
If higher temperatures are required, alloy steel grades such as ASTM A234 WP11 or WP22 should be selected.
Quality Inspection
GNEE implements strict quality control at every stage:
- Incoming material inspection: Chemical composition and mechanical testing.
- In-process inspection: Dimensional control and forming quality.
- Final inspection: Visual inspection, UT, PMI, and hydrostatic testing.
- Certification: ISO 9001, EN 10204 3.1 MTC, and optional third-party inspection (SGS/BV/TÜV).
This ensures consistent reliability and compliance with international standards.
Applications
ASTM A234 WPB eccentric reducers are widely used in:
- Oil & gas pipeline systems (upstream, midstream, downstream)
- Chemical and petrochemical plants
- Water and wastewater treatment facilities
- Power plants and steam lines
- Industrial piping requiring smooth flow transitions
GNEE ASTM A234 WPB Eccentric Reducer factory
GNEE ASTM A234 WPB Eccentric Reducer Test equipments
GNEE ASTM A234 WPB Eccentric Reducer Certificate
FAQ
What is ASTM A234 grade WPB?
ASTM A234 Grade WPB is the most common standard material for carbon steel butt-weld pipe fittings (such as elbows, tees, and reducers).
What is the difference between WPB and WPC in ASTM A234?
The main difference between WPB and WPC is their strength and chemical composition.
Strength: WPC is stronger than WPB.
WPB: Yield strength ≥35,000 psi; Tensile strength ≥ 60,000 psi.
WPC: Yield strength ≥ 40,000 psi; Tensile strength ≥ 70,000 psi.
Chemical Composition: WPC has slightly higher limits for Carbon (0.35% vs 0.30%) and Manganese (0.29–1.06% vs 1.06–1.65%), which accounts for its higher strength.
Application:
WPB is the most common, "standard" grade used worldwide for general oil and gas pipelines.
WPC is used when higher pressure or strength is required, often specifically to match ASTM A106 Grade C pipes.
What is the difference between ASTM A234 WPB and ASTM A105?
The main difference between ASTM A234 WPB and ASTM A105 lies in the type of product and the manufacturing process:
Product Type:
ASTM A234 WPB: Used for butt-weld fittings (elbows, tees, reducers, caps).
ASTM A105: Used for forged components (flanges, valves, and small-diameter high-pressure fittings like socket-weld elbows).
Manufacturing Process:
A234 WPB is wrought, meaning it is made from pipes, tubes, or steel plates through heating and forming.
A105 is forged, meaning it is shaped from solid steel bars or ingots using heat and intense pressure (hammering or pressing).
Raw Material:
A234 WPB usually starts as a pipe (like ASTM A106 Gr.B).
A105 starts as a solid steel bar.
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