Carbon Steel Concentric Reducer — Factory Direct Supplier | Huaxia-Steel

Carbon steel concentric reducers are pipe fittings that join two pipes of different diameters with a common centerline, maintaining symmetrical flow for pumps, compressors, and vertical pipelines. Huaxia-Steel manufactures seamless and welded concentric reducers from ½ inch to 48 inches (DN15–DN1200), in schedules SCH 10–SCH 160 and XS/XXS, to ASTM A234 WPB, ASTM A105, MSS SP-75, and EN 10253-2, with beveled ends ready for butt welding.

Product Overview

Concentric reducers taper evenly around the center axis, unlike eccentric reducers which offset the centerline to maintain flat top or bottom surfaces. The concentric design is preferred for horizontal liquid lines and vertical installations where air pocketing is not a concern. Our reducers are produced by hot forming (hydraulic press or mandrel) for seamless types, and by plate forming and longitudinal welding for large-diameter welded types. After forming, reducers are heat-treated (normalizing or quench-and-temper for high-strength grades), machined on the ends for bevel angle and land dimension, and inspected for wall thickness, ovality, and surface integrity.

Specifications

Parameter	Details
Size range	½” × ¼” to 48″ × 36″ (DN15–DN1200)
Wall schedule	SCH 10, 20, 40, 80, 120, 160; XS, XXS
Type	Seamless (up to 24″) or welded (18″–48″)
End preparation	Plain bevel 37.5° ± 2.5°, land 1.6 mm; compound bevel on request
Materials	ASTM A234 WPB, WPC; ASTM A105; A420 WPL6; MSS SP-75 WPHY 42–70
Carbon steels	A106 Gr B, A53 Gr B, API 5L Gr B/X42/X52, S235, S355, C20, St37
Standards	ASME B16.9, MSS SP-75, EN 10253-2, GOST 17378, GB/T 12459
Surface	Black, shot-blasted, pickled, or rust-preventive oil

Dimensional Tolerances per ASME B16.9

Dimension	Tolerance
Outside diameter at large end	+3.2 mm / –0.8 mm (for OD ≤ 48″)
Outside diameter at small end	+2.4 mm / –0.8 mm
Overall length (center-to-end)	±3.2 mm
Wall thickness	Not less than 87.5% of nominal thickness
Ovality	≤ 1% of OD for OD > 200 mm
Bevel angle	37.5° ± 2.5°

Material and Grade Selection Guide

Service condition	Recommended grade	Notes
General water, air, oil	A234 WPB	Standard carbon steel, -20°C to 425°C
Low-temperature service	A420 WPL6	Impact tested to -46°C
High-strength pipelines	MSS SP-75 WPHY 52/60	Higher yield for API 5L matching
Sour service (H₂S)	A234 WPB + NACE MR0175 hardness limit	Max 22 HRC; hardness test required

Manufacturing Standards and Quality Control

Production follows ISO 9001 and PED 2014/68/EU where CE marking is required. Incoming pipe or plate is checked for chemistry, tensile properties, and ultrasonic integrity. Forming temperature and press force are recorded per heat. Post-form heat treatment uses continuous furnaces with certified temperature uniformity ±10°C. Final inspection includes dimensional checks with CMM or templates, wall thickness measurement by ultrasonic gauge at four quadrants, magnetic particle or liquid penetrant inspection of welds and surfaces, and hydrostatic testing when specified. All reducers are marked with heat number, size, schedule, standard, and country of origin.

Applications

• Process piping in refineries, chemical plants, and power stations
• Water treatment and desalination plant headers
• HVAC chilled water and steam distribution
• Pipeline pump and compressor suction/discharge
• Shipbuilding bilge and ballast systems
• Structural pipe racks and support transitions

Packaging and Shipping

Small reducers (≤ 8″) are packed in wooden crates with separators to prevent surface damage. Large reducers (≥ 10″) are shipped loose on pallets or steel racks with padded contact points. Bevel edges are protected with plastic caps or cardboard rings. Each package includes a packing list with heat numbers, dimensional report, and MTC reference. For ocean freight, we apply rust-preventive oil and VCI film wrapping. Urgent air-freight orders are packed to IATA standards with full documentation.