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Changzhou Fenglan New Materials Co., Ltd.

Straight Union Pipe Fitting

-- Steady & Reliable Manufacturer --

Introduction

Straight union pipe fittings — also referred to as straight connectors or inline couplings — join two pipes or tubes in a direct, collinear run. Unlike elbows or tees, they add no change of direction, making them the cleanest way to extend a line, join two different tube sizes (reducing unions), or connect sections of the same bore.

Fenglan manufactures straight union fittings in push-in, compression, and threaded end styles across a wide size range. Our CNC-machined brass and stainless steel unions feature consistent thread profiles, smooth bore transitions, and tight dimensional tolerances, ensuring they seal reliably first time — whether you are building a high-volume pneumatic manifold or a one-off prototype fluid circuit.

Equal-bore and reducing variants are both catalogued as standard. Custom bore steps, special face-seal grooves, and non-standard thread combinations can be produced to drawing within typical prototype lead times of 7–10 days.

Related Products

Specifications

Configuration Equal bore union; reducing union (step-down / step-up)
Tube OD Range 4 mm – 25 mm; 1/8" – 1"
Thread Options BSPP (G), BSPT (R), NPT, Metric parallel/tapered
End Connection Type Push-in both ends, compression both ends, M×F threaded, barb
Body Material C36000 brass, 304 SS, 316 SS, 6061 aluminum, PA66
Max Working Pressure 1.5 MPa (PA) / 4 MPa (brass) / 6 MPa (SS)
Temperature Range -20 °C to +200 °C (material dependent)
Seal Type NBR O-ring, PTFE, FKM (optional)
Surface Treatment Nickel-plated, plain, anodized (aluminum)
Custom Bore Steps Available on request — specify inlet/outlet OD in inquiry

Applications

  • Pneumatic Distribution Lines: Joining two sections of compressed air tubing within automation enclosures or inline with shut-off valves.
  • Hydraulic Manifolds: Inline connections in power units, servo valve blocks, and cylinder-feed circuits that demand zero-leak performance.
  • Water Treatment Equipment: Inline coupling of filter housings, dosing pump outlets, and RO membrane housings.
  • Laboratory Instruments: Gas chromatography, sample delivery systems, and analytical equipment where small-bore, leak-free connections are critical.
  • Reducing Applications: Adapting legacy 1/4" BSP lines to modern 6 mm push-in systems without replacing complete circuits.

Advantages

  • Zero-Step Flow Path: A smooth, burr-free bore with no abrupt diameter steps minimizes pressure drop and turbulence, important in high-flow and sensitive measurement applications.
  • Full Dismountability: Unlike soldered or crimped fittings, union-style connections can be disassembled for maintenance and re-assembled without replacement.
  • Reducing Variants in Stock: Common reducing combinations (e.g., 8 mm → 6 mm, 1/2" → 3/8") are held in inventory for fast dispatch.
  • CNC Precision: Thread form accuracy to 6H tolerance ensures predictable assembly torque and leak-free seating every time.
  • Multi-Material Availability: Single-source supply across brass, stainless, and aluminum simplifies procurement for mixed-material systems.

Payment & Shipping

Payment Terms: We accept T/T (wire transfer), L/C at sight, PayPal, and Western Union. A 30% deposit is required before production begins, with the remaining 70% settled before shipment. For established long-term customers, flexible credit arrangements can be discussed on a case-by-case basis.

Lead Time: Standard production lead time is 7–15 business days after deposit confirmation. For urgent orders, expedited scheduling may be available — please contact our sales team to check availability.

Shipping & Logistics: We ship worldwide via DHL, FedEx, UPS, TNT, and by sea (LCL or FCL). Incoterms supported include EXW, FOB Ningbo/Shanghai, CIF, and CFR. The most cost-effective option is selected based on order weight and destination.

Packaging: All items are individually inspected, then packed in anti-rust film and foam-lined export cartons. Custom branding, inner packaging, and labeling are available on request. Packaging fully complies with international freight standards.

Quality Assurance: Every shipment is accompanied by an inspection report and, where applicable, material certificates (e.g., RoHS, REACH). We support third-party inspection arrangements (SGS, BV, etc.) if required.

FAQ

  • Q: What is the difference between a union and a coupling fitting?
  • A: A union is a three-piece assembly (two threaded ends and a middle nut) that allows the joint to be separated from either side without disturbing the rest of the pipeline. A coupling is typically a two-piece compression or welded fitting. Unions are preferred where regular maintenance access is expected.
  • Q: Do you supply reducing straight unions as standard catalog items?
  • A: Yes. Common reducing combinations in brass push-in and BSP threaded styles are stocked. If your specific size combination is not listed, we can produce it as a custom order — typically within 7–10 working days.
  • Q: How do I specify a straight union fitting for a high-vibration environment?
  • A: For vibration-prone installations, we recommend selecting compression-style or push-in fittings with vibration-resistant collets, combined with a lock nut or secondary securing feature. Specify the operating frequency and amplitude in your inquiry so we can recommend the right option.
  • Q: Can you produce straight union fittings with face-seal (O-ring face seal / ORFS) ends?
  • A: Yes, ORFS-end straight unions are available in both equal-bore and reducing configurations in 316 SS and brass. ORFS connections offer superior leak integrity under dynamic pressure and vibration compared to tapered-thread connections.
Changzhou Fenglan New Materials Co., Ltd.
Changzhou Fenglan New Materials Co., Ltd.
Changzhou Fenglan New Materials Co., Ltd.
Changzhou Fenglan New Materials Co., Ltd.
Changzhou Fenglan New Materials Co., Ltd.
Changzhou Fenglan New Materials Co., Ltd.
Changzhou Fenglan New Materials Co., Ltd.
Changzhou Fenglan New Materials Co., Ltd.
ABOUT US
Quality is Our Core Competitiveness
Changzhou Fenglan New Materials Co., Ltd.
Founded in 2010, As China Straight Union Pipe Fitting Manufacturers and Straight Union Pipe Fitting Company. we are dedicated to manufacturing precision parts for automotive, industrial, and electrical applications. Backed by advanced manufacturing and R&D, we provide high-quality products and trusted solutions to our clients. We provide a wide selection of components to meet diverse industry needs: Electric Shafts: Drive shafts, coil motor shafts, servo motor shafts, water pump motor shafts, industrial motor shafts, and magnetic levitation motor shafts. Hardware: Precision parts for medical equipment, water heater coils, plumbing fittings, and various gas springs. Our commitment is to support our customers with reliable performance and long-term value.
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  • Changzhou Fenglan New Materials Co., Ltd.
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