Concentric Reducer Fitting | ASME B16.9 | Seamless
Engineered concentric reducer fitting for reliable pipe size reduction. Available in stainless steel, carbon steel, with butt weld, socket weld connections. ASME B16.9 compliant. Get a fast quote now!
Description
Concentric Reducer Fitting | ASME B16.9 | Seamless
Concentric Reducer Fitting is a core component for smooth diameter transition in piping systems. It features a coaxial centerline, which effectively reduces turbulence and pressure loss.
Our supplied concentric reducers are manufactured in strict accordance with ASME B16.9 and MSS SP-43 standards, widely applicable to petrochemical, pharmaceutical, food processing and high-pressure steam pipeline networks.
Materials
- Stainless Steel (Stainless Concentric Reducer): ASTM A403 WP304/304L, 316/316L. With outstanding corrosion resistance, it is ideal for acid-base media and sanitary pipeline systems.
- Carbon Steel: ASTM A234 WPB, suitable for high-temperature and high-pressure working conditions such as main steam pipelines in power plants.
- Alloy Steel: P11, P22 and other grades, meeting requirements for hydrogen sulfide resistance and low-temperature impact resistance.
Connection Methods of Concentric Reducer Fitting
- Butt Weld: Designed for large-diameter and high-pressure systems. We adopt professional concentric weld reducer processing technology to ensure the weld strength is consistent with the base metal.
- Socket Weld: Available for small size ranging from NPS 1/2” ~ 4”. The concentric reducer socket weld type enables convenient on-site installation and low leakage risk.
- Threaded Connection: Customizable in compliance with NPT standards.
Pressure Rating
- Wall Thickness Schedule: Sch10S, Sch40S, Sch80, Sch160, XXS.
- Pressure Class: For stainless steel products, the maximum pressure rating can reach 2500# (socket weld end) at room temperature. Butt weld reducers can withstand Class 150 ~ 2500 depending on the pipe schedule.
Features of Concentric Reducer Fitting
- Smooth Transition: The concentric structure ensures consistent fluid flow direction and reduces eddy current and pipeline vibration.
- Full-scale Inspection: Every unit is processed with ultrasonic thickness measurement, and X-ray detection is optional to eliminate defects such as pores and cracks.
- High Interchangeability: All concentric pipe fittings are produced in line with international standards, perfectly compatible with flanges, valves and pipe segments of all brands.
Concentric Reducer Fitting Dimension Chart (Stainless Steel / Carbon Steel, Butt Weld End)
| Nominal Pipe Size (NPS) | OD at Large End (mm) | OD at Small End (mm) | Length (mm) | Wall Thickness Schedule |
|---|---|---|---|---|
| 2″ × 1″ | 60.3 | 33.4 | 76 | Sch40 / Sch80 |
| 3″ × 2″ | 88.9 | 60.3 | 89 | Sch40 / Sch80 |
| 4″ × 2½” | 114.3 | 73.0 | 102 | Sch40 / Sch80S |
| 6″ × 4″ | 168.3 | 114.3 | 127 | Sch40 / Sch80 |
| 8″ × 6″ | 219.1 | 168.3 | 152 | Sch10S / Sch40 |
Note: Custom special sizes and wall thicknesses from NPS 1/2” to 48” are available.
Application Scenarios
- Chemical Plants: Applied at inlet and outlet pipelines of reactors. Stainless concentric reducer is adopted to resist impact from corrosive fluid.
- Oil & Gas Transportation: Butt weld concentric reducers are used for diameter connection in gathering and transmission pipelines to lower stress concentration.
- High-pressure Steam Systems: Used for diameter transition of boiler main steam pipelines in power stations, with qualified concentric structure and radiographic inspection required.
- Water Treatment & Food-grade Pipelines: Equipped with sanitary polished inner wall to avoid residue accumulation.
AIFN implements full-process quality control covering raw material re-inspection, heat treatment and traceability marking. Each concentric reducer can be supplied with EN 10204 3.1 certification. Custom non-standard dimensions and special alloy materials (Inconel, Monel, etc.) are available upon request. Feel free to send your inquiry.
Q&A
Q: Can a concentric reducer fitting be used in vertical piping with downward flow?
A: Yes, a concentric reducer fitting is generally suitable for vertical downward flow because its symmetrical bore maintains steady velocity distribution and minimizes turbulence. However, for upward vertical flow or when the line carries two-phase mixtures (liquid + gas), an eccentric reducer with flat side up is recommended to prevent vapor pocket accumulation. Always verify your process conditions; for clean single-phase liquid or gas, concentric types work reliably in both horizontal and vertical orientations. Our engineering team can advise based on your specific pressure, temperature, and fluid properties.
More Products
Need a 2 inch 90 degree elbow steel for your pipeline? Durable carbon steel & stainless options, suitable for high-pressure systems. Fast delivery. Read more.
High-quality 2 inch steel pipe 90 degree elbow for reliable directional change in piping systems. Corrosion-resistant, multiple schedules, ideal for industrial applications. Fast shipping.
Engineered concentric reducer fitting for reliable pipe size reduction. Available in stainless steel, carbon steel, with butt weld, socket weld connections. ASME B16.9 compliant. Get a fast quote now!
Durable cross pipe fitting for 4-way connections. Black iron, steel, reducing cross types available. For gas, water, hydraulic systems. Request a quote!