✅ Professional Industrial Flange Manufacturer in China
We are a professional manufacturer of industrial flanges for EPC projects, power plants, petrochemical, oil & gas, metallurgy, water treatment, and piping systems. An industrial flange is a forged or machined ring used to connect pipes, valves, pumps, and other equipment in a piping system, providing a secure, leak-proof, and dismantlable joint. Our product portfolio includes weld neck flanges, slip-on flanges, blind flanges, threaded flanges, socket weld flanges, lap joint flanges, and ring type joint (RTJ) flanges, manufactured in carbon steel, stainless steel, alloy steel, and duplex stainless steel. All products comply with ASME B16.5, ASME B16.47, ASTM A105, ASTM A182, and EN 1092-1 standards, available in pressure classes 150 to 2500 and sizes NPS 1/2 to NPS 60.
An industrial flange is a critical piping component that provides a bolted connection between two pipes, a pipe and a fitting, or a pipe and equipment. The flange joint consists of three essential parts: flanges, gasket, and bolts/nuts[reference:0]. The flange design and material must match the pressure rating, temperature, and corrosive environment of the piping system. Key features include:
| Feature | Description |
|---|---|
| Full Range of Flange Types | Weld neck, slip-on, blind, threaded, socket weld, lap joint, and RTJ configurations |
| ASME B16.5 / B16.47 Compliance | Pressure classes 150, 300, 400, 600, 900, 1500, 2500; sizes NPS 1/2 to NPS 60[reference:1] |
| Multiple Material Grades | Carbon steel (ASTM A105, A350 LF2), stainless steel (A182 F304/F316), alloy steel, duplex |
| Precision Machining | CNC machining for accurate dimensions, bolt hole alignment, and sealing face finish |
| Multiple Facing Options | Raised face (RF), flat face (FF), ring type joint (RTJ) |
| High Integrity Joint | Weld neck flanges provide the highest joint integrity for high pressure/temperature service[reference:2] |
| Full Traceability | EN 10204 3.1 certificates, heat number traceability, PMI testing available |
| Wide Application Range | Power plants, petrochemical, oil & gas, water treatment, shipbuilding, EPC projects |
| Flange Type | Attachment Method | Key Characteristics | Typical Application |
|---|---|---|---|
| Weld Neck (WN) | Butt weld to pipe | Highest joint integrity; tapered hub transfers stress; radiographable weld[reference:3] | High pressure/temperature, critical process piping[reference:4] |
| Slip-On (SO) | Fillet weld (inside & outside) | Easy alignment; lower strength (~1/3 of WN); economical[reference:5] | Low/medium pressure and temperature[reference:6] |
| Blind (BL) | Bolted (no pipe connection) | Blank disc for sealing pipe ends or isolating equipment[reference:7] | Pipe termination, manhole covers, system isolation |
| Threaded (THD) | Threaded connection | No welding required; not for high pressure/temperature or severe service[reference:8] | Small bore utility lines (air, water)[reference:9] |
| Socket Weld (SW) | Fillet weld (outside only) | Good flow characteristics; limited to small bore; not for severe service[reference:10] | Small diameter high-pressure lines[reference:11] |
| Lap Joint (LJ) | Stub end + loose backing flange | Flange can rotate for bolt alignment; economical for costly pipe material[reference:12] | Frequent dismantling, space-constrained, stainless pipe with CS flange[reference:13] |
| RTJ (Ring Type Joint) | Metal ring gasket in groove | High-integrity metal-to-metal seal; for high pressure/hazardous fluids[reference:14] | High pressure/temperature, oil & gas, flammable/toxic media[reference:15] |
| Parameter | Specification Range |
|---|---|
| Standards | ASME B16.5 (NPS 1/2–24), ASME B16.47 (NPS 26–60), EN 1092-1, DIN, JIS |
| Pressure Classes | 150, 300, 400, 600, 900, 1500, 2500 (ASME); PN 6, 10, 16, 25, 40, 63, 100 (EN)[reference:16] |
| Size Range | NPS 1/2 to NPS 24 (B16.5); NPS 26 to NPS 60 (B16.47); DN15 to DN3000+ |
| Carbon Steel Materials | ASTM A105 (standard), ASTM A350 LF2 (low-temperature, -46°C)[reference:17] |
| Stainless Steel Materials | ASTM A182 F304, F304L, F316, F316L, F321, F347[reference:18] |
| Duplex / Alloy Materials | ASTM A182 F51 (Duplex 2205), F53, F55, Nickel alloys (Monel, Inconel, Hastelloy) |
| Facing Types | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)[reference:19] |
| RF Height | 1.6mm for Class 150/300; 6.4mm for Class 400–2500[reference:20] |
| Manufacturing Method | Forged (standard for ASME flanges); cast and plate available for specific applications[reference:21] |
| Surface Finish (RF/FF) | 125–250 µin Ra (standard); smooth finish for soft gaskets available |
| Temperature Range | -46°C (A350 LF2) to +500°C+ (depending on material and pressure class) |
| Testing & Certification | EN 10204 3.1 mill certificates; PMI, hardness, dimensional inspection, NDT available |
| Application | Power plants, petrochemical, oil & gas, water treatment, shipbuilding, EPC projects |
* Custom dimensions, materials, and facing configurations are available upon request for EPC project tenders.
| Material | Group | Max. Pressure @ 100°F (38°C) |
|---|---|---|
| ASTM A105 (Carbon Steel) | 1.1 | 1,480 psig (102.0 bar)[reference:22] |
| ASTM A350 LF2 (Low-Temp CS) | 1.1 | 1,480 psig (102.0 bar)[reference:23] |
| ASTM A182 F304 (Stainless) | 2.1 | 1,440 psig (99.3 bar)[reference:24] |
| ASTM A182 F316 (Stainless) | 2.3 | 1,440 psig (99.3 bar)[reference:25] |
* Full PT rating tables per ASME B16.5 are available upon request. Ratings vary with temperature and material group.
| Application Condition | Recommended Flange Type | Reason |
|---|---|---|
| High pressure / High temperature process piping | Weld Neck | Highest joint integrity, radiographable weld, stress transfer[reference:26] |
| Low/medium pressure, general service | Slip-On | Economical, easy alignment[reference:27] |
| Pipe end sealing / System isolation | Blind | Complete shut-off, reusable[reference:28] |
| Small bore utility lines (no welding) | Threaded | Quick assembly, no hot work[reference:29] |
| Small bore high-pressure lines | Socket Weld | Good flow, compact[reference:30] |
| Frequent dismantling / Costly pipe material | Lap Joint | Rotatable flange, economical backing ring[reference:31] |
| High pressure / Hazardous / Toxic media | RTJ | Metal-to-metal seal, highest integrity[reference:32] |
| Corrosive media / Low temperature | Stainless / A350 LF2 | Material selection for environment[reference:33] |
Q1: What is an industrial flange?
A: An industrial flange is a forged or machined ring used to connect pipes, valves, pumps, and other equipment in a piping system. The flange joint consists of three integral parts: flanges, gasket, and bolts/nuts, providing a secure, leak-proof, and dismantlable connection[reference:34].
Q2: What are the main types of industrial flanges?
A: The main types include: Weld Neck (WN) — butt welded, highest integrity; Slip-On (SO) — fillet welded, economical; Blind (BL) — for sealing pipe ends; Threaded (THD) — screwed connection; Socket Weld (SW) — for small bore; Lap Joint (LJ) — with stub end; and RTJ — metal ring joint for high pressure[reference:35].
Q3: What is the difference between weld neck and slip-on flanges?
A: Weld neck flanges are butt-welded to the pipe and have a long tapered hub that transfers stress, providing the highest joint integrity for high pressure/temperature service. Slip-on flanges slip over the pipe and are fillet welded inside and outside, offering lower strength (~1/3 of WN) but easier alignment and lower cost[reference:36][reference:37].
Q4: What standards do your industrial flanges comply with?
A: Our flanges comply with ASME B16.5 (NPS 1/2–24, Class 150–2500), ASME B16.47 (NPS 26–60), EN 1092-1, and other international standards as required[reference:38][reference:39].
Q5: What pressure classes are available?
A: ASME pressure classes: 150, 300, 400, 600, 900, 1500, and 2500. EN pressure ratings: PN 6, 10, 16, 25, 40, 63, 100[reference:40].
Q6: What size range do you offer?
A: ASME B16.5: NPS 1/2 to NPS 24. ASME B16.47: NPS 26 to NPS 60. Metric sizes available from DN15 to DN3000+.
Q7: What materials are used for industrial flanges?
A: Carbon steel: ASTM A105, A350 LF2 (low-temperature). Stainless steel: A182 F304, F304L, F316, F316L, F321, F347. Duplex/alloy: F51 (2205), F53, F55, and nickel alloys[reference:41][reference:42].
Q8: What is the difference between ASTM A105 and A350 LF2?
A: A105 is the standard carbon steel forging for flanges, suitable for service down to -29°C. A350 LF2 is a low-temperature carbon steel with impact toughness tested for service down to -46°C[reference:43].
Q9: What are the facing options?
A: Raised Face (RF) — most common, for general process piping (Class 150–2500). Flat Face (FF) — for low pressure and cast iron/FRP mating. RTJ — metal ring joint for high pressure/hazardous service[reference:44].
Q10: What is the RF height?
A: For Class 150/300, the raised face height is 1.6mm (1/16"). For Class 400–2500, it is 6.4mm (1/4")[reference:45].
Q11: When should I use an RTJ flange?
A: RTJ flanges are used for high pressure, high temperature, and hazardous fluid applications where a metal-to-metal seal is required. The metal ring gasket sits in a groove on the flange face, providing a high-integrity seal[reference:46][reference:47].
Q12: What is a lap joint flange used for?
A: Lap joint flanges are used where frequent dismantling is required or where the pipe material is costly (e.g., stainless steel). The stub end is butt-welded to the pipe, and the backing flange rotates freely for easy bolt alignment[reference:48][reference:49].
Q13: What is the difference between a blind flange and a spectacle blind?
A: A blind flange is a solid disc bolted to a flange to completely seal a pipe end or isolate equipment. A spectacle blind (figure-8 blank) combines a blind and a spacer in one piece, allowing quick switching between open and closed positions without removing the flange from the line.
Q14: Can threaded flanges be used in high-pressure service?
A: No. Threaded flanges are not recommended for high pressure, high temperature, or severe service (limited to ≤250°C and not below -45°C). They are used for small-bore utility lines where welding is impractical[reference:50][reference:51].
Q15: What is the temperature limit for socket weld flanges?
A: Socket weld flanges are not recommended for service above 250°C or below -45°C. They are limited to small bore piping and are not suitable for severe service[reference:52].
Q16: How do I select the correct flange for my application?
A: Key factors: (1) Pressure class — match system design pressure; (2) Temperature — verify material PT rating at operating temperature; (3) Material — carbon steel for general, stainless for corrosive, LF2 for low-temp; (4) Flange type — based on joint integrity and maintenance requirements; (5) Facing type — RF/FF/RTJ based on gasket and service; (6) Size — match pipe NPS/DN.
Q17: What certificates are provided with your flanges?
A: Standard: EN 10204 3.1 mill test certificates. Additional services: PMI (Positive Material Identification) testing, hardness testing, dimensional inspection, NDT (UT, MT, PT), and full heat number traceability[reference:53].
Q18: What are the typical applications of industrial flanges in EPC projects?
A: Power plants — steam and water piping; Petrochemical — process piping and equipment connections; Oil & gas — wellhead, pipeline, and refinery; Water treatment — pump and valve connections; Shipbuilding — marine piping systems[reference:54][reference:55].
Q19: Do you support EPC projects with technical documentation?
A: Yes. We provide datasheets, dimension drawings, material certificates, PT rating data, FAT reports, and full traceability documentation for EPC project compliance. We work with global EPC contractors in power, petrochemical, and infrastructure sectors.
Q20: Can you provide custom flange configurations?
A: Yes. We offer custom sizes, materials, pressure classes, facing types, and special dimensions to meet project-specific requirements. Our engineering team can review your piping specifications and recommend the optimal flange solution.
Send your piping specification, flange schedule, or project requirements. Our engineering team will reply with a customized BOM, datasheet & material certificates within 24 hours.
WhatsApp / Zalo: +86 17856068126 | Email: [email protected]
Founded in 1974, Anhui Tiankang Group is a cross-industry and diversified conglomerate. Its core products cover instruments and meters, optical and e...
Copyright © 2026 ANHUI TIANKANG（GROUP） SHARES CO.,LTD XML
