Union
- Our forged pipe unions are made of premium carbon steel, alloy steel and stainless steel, with reliable high-pressure sealing and excellent corrosion resistance. Consist of three detachable parts: two ends and a hexagonal lock nut. Precision CNC thread machining ensures leak-free connection and easy disassembly. Strict full-process inspection guarantees stable mechanical performance. Widely applied in oil & gas, petrochemical, power, marine, water treatment and plumbing piping systems.
Certified:
All unions are equipped with complete factory test reports covering chemical composition, mechanical properties, dimensional inspection, NDT and hydrostatic testing. Products comply with ISO, ASTM, ASME, DIN, EN and JIS standards. Material mill certificates EN 10204 3.1 / 3.2, third-party inspection certificates and full shipping documents can be provided on request to realize full quality traceability for global industrial buyers.
Application:
Unions are detachable three-piece pipe connectors widely used in industrial piping systems for convenient pipeline disassembly and maintenance. In oil & gas transmission, they create removable joints under high temperature and pressure for crude oil and natural gas pipelines. Petrochemical plants adopt anti-corrosion unions for quick disconnection of reactor, storage tank and corrosive medium pipelines without cutting pipes.
Thermal and nuclear power stations use high-temperature resistant unions on auxiliary steam and cooling pipes to facilitate valve and pump overhaul. Marine and offshore engineering utilizes seawater-resistant unions for fuel, ballast and fire-fighting pipelines on vessels and platforms. Water treatment and desalination projects equip unions on pump and filter connecting pipelines for easy component replacement. In construction, unions are widely installed in HVAC, fire protection and plumbing systems for later pipeline modification. Sanitary stainless steel unions are used in food and pharmaceutical production lines to meet strict hygiene standards without medium contamination.
Specification:
1. Product Specification
Parameter | Detailed Specification |
Product Type | Threaded Union, Socket Weld Union, Flat Seat Union, Conical Seat Union, Forged Union |
Size Range | 1/8" – 4" (DN6 – DN100), customized sizes available |
Pressure Rating | 2000LB, 3000LB, 6000LB (Class 150 – Class 2500 equivalent) |
End Connection | SW Socket Weld, NPT/BSP Threaded |
Manufacturing Process | Hot Forging, Heat Treatment, CNC Thread Machining, Polishing |
Applicable Standards | ASME B16.11, MSS SP-83, DIN 2628, EN 10253, JIS B2316, ISO 4144 |
Material Grades | Carbon Steel: A105, A234 WPB / Stainless Steel: 304, 304L, 316, 316L, 321, 904L / Alloy Steel: A182 F11, F22, F91 |
2. Chemical Composition
Grade | C | Si | Mn | P | S | Cr | Ni | Mo |
A234 WPB | ≤0.30 | ≤0.35 | 0.29–1.06 | ≤0.035 | ≤0.035 | ≤0.40 | ≤0.40 | — |
WP11 | 0.05–0.15 | 0.50–1.00 | 0.30–0.60 | ≤0.030 | ≤0.030 | 1.00–1.50 | — | 0.44–0.65 |
WP22 | 0.05–0.15 | ≤0.50 | 0.30–0.60 | ≤0.030 | ≤0.030 | 2.00–2.50 | — | 0.87–1.13 |
304 | ≤0.08 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 18.0–20.0 | 8.00–10.5 | — |
304L | ≤0.03 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 18.0–20.0 | 8.00–12.0 | — |
316 | ≤0.08 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 16.0–18.0 | 10.0–14.0 | 2.00–3.00 |
316L | ≤0.03 | ≤0.75 | ≤2.00 | ≤0.045 | ≤0.030 | 16.0–18.0 | 10.0–14.0 | 2.00–3.00 |
Standard:
Classification | Grade | Applicable Standard | Key Chemical Composition (wt%) | Key Mechanical Properties (Room Temperature) |
Carbon Steel | A234 WPB | ASTM A234 | C≤0.30, Mn 0.29~1.06, S≤0.035, P≤0.035 | TS≥415MPa, YS≥205MPa, EL≥22%, H≤156HB |
Low Alloy Steel | WP11 | ASTM A234 | C 0.05~0.15, Cr 1.00~1.50, Mo 0.44~0.65 | TS≥415MPa, YS≥205MPa, EL≥20%, H≤163HB |
WP22 | ASTM A234 | C 0.05~0.15, Cr 2.00~2.50, Mo 0.87~1.13 | TS≥415MPa, YS≥205MPa, EL≥20%, H≤163HB | |
Austenitic Stainless Steel | 304 | ASTM A403 | C≤0.08, Cr 18.0~20.0, Ni 8.00~10.5 | TS≥520MPa, YS≥205MPa, EL≥35%, H≤90HRB |
304L | ASTM A403 | C≤0.03, Cr 18.0~20.0, Ni 8.00~12.0 | TS≥480MPa, YS≥170MPa, EL≥35%, H≤90HRB | |
316 | ASTM A403 | C≤0.08, Cr 16.0~18.0, Ni 10.0~14.0, Mo 2.00~3.00 | TS≥520MPa, YS≥205MPa, EL≥35%, H≤90HRB | |
316L | ASTM A403 | C≤0.03, Cr 16.0~18.0, Ni 10.0~14.0, Mo 2.00~3.00 | TS≥480MPa, YS≥170MPa, EL≥35%, H≤90HRB | |
321 | ASTM A403 | C≤0.08, Cr 17.0~19.0, Ni 9.00~12.0, Ti≥5×C | TS≥520MPa, YS≥205MPa, EL≥35%, H≤90HRB |
Process:
Packing:
