PRODUCT FEATURES
Union Conical M/F — Product Features
Steam piping, hot water systems, water treatment, machinery process piping, food & beverage, heating circuits, pump & valve connections, high-temperature lines where PTFE gaskets cannot be used, pipelines requiring frequent disassembly.
Product Feature
Buyer Notes
Product Feature
EN 10204 3.1 material test certificate available for bulk orders. OEM marking is acceptable. Samples can be supplied for dimensional inspection and leak test before mass production. Please confirm thread type and size before order. Since this is metal conical sealing, proper tightening torque is required for good sealing.
OPERATING PRINCIPLE
How Union Conical M/F Works
1. **Male/Female (M/F) Conical-Seat Union**: Features a male thread on one end and a female thread on the other; utilizes a metal-to-metal conical sealing design, eliminating the need for soft gaskets.
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2. **Three-Piece Construction**
Comprises two main body components and a hexagonal union nut, facilitating easy installation and disassembly.
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3. **Metal Conical-Seat Seal**
Mating surfaces are precision-machined; once tightened to the specified torque, they form a tight, leak-proof seal, making them suitable for high-temperature applications.
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4. **AISI 304 Stainless Steel**
Offers excellent rust and corrosion resistance; suitable for use with fresh water, steam, and mildly corrosive media.
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5. **Precision-Machined Threads**
Available with BSPP, BSPT, or NPT threads; thread tolerances comply with ISO 7-1, DIN 2999, or ANSI B1.20.1 standards.
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6. **PN20 (150LB) Pressure Rating**
Complies with the ISO 4144 standard, ensuring stable performance under rated operating pressures.
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7. **Pickled and Passivated Surface**
Provides a clean metal surface and further enhances corrosion resistance; supports customized marking.
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8. **Comprehensive Size Range**
Available in a full range of sizes from 1/4″ to 2-1/2″ (DN8 to DN65).
ENGINEERING DATA
Technical Specifications
Technical data supplied for Union Conical M/F. Ratings and material combinations should be confirmed for the selected configuration.
| PARAMETER | SPECIFICATION |
|---|---|
| Material | AISI 304 (1.4301 / ASTM A182 F304) |
| Type | Union Conical M/F, Conical Seat Male × Female Thread Union |
| Thread Standard | NPT (ANSI B1.20.1) / BSPT / BSPP (ISO7/1, DIN2999) |
| Pressure Class | PN20 (150LB, 20 bar) |
| Standard | ISO 4144 |
| Seal Type | Conical metal to metal sealing (gasketless) |
| Surface | Pickled & passivated |
| Working Temperature | -20℃ ~ +250℃ |
MECHANICAL DIMENSIONS
Dimensions & drawings.
Compare connection size with the corresponding overall length, bore and handle clearance dimensions from the supplied drawing.
Dimension chart
| SIZE | L1 | L2 | D1 | D2 | D3 | D4 | D5 | H |
|---|---|---|---|---|---|---|---|---|
| 1/4″ | 9 | 9 | 12 | 12 | 11.5 | 13 | 17 | 44 |
| 3/8″ | 10 | 10 | 13 | 13 | 15 | 16 | 20 | 46 |
| 1/2″ | 10 | 10 | 15 | 15 | 18.5 | 20 | 24 | 53 |
| 3/4″ | 12 | 12 | 16 | 16 | 24 | 26 | 30 | 56 |
| 1″ | 14 | 14 | 17 | 17 | 30 | 32 | 37 | 62 |
| 1-1/4″ | 15 | 15 | 19 | 19 | 39 | 41 | 46 | 71 |
| 1-1/2″ | 17 | 17 | 22 | 22 | 45 | 47 | 52 | 74 |
| 2″ | 18 | 18 | 22 | 22 | 56 | 59 | 65 | 82 |
| 2-1/2″ | 20 | 20 | 25 | 25 | 72 | 75 | 80 | 93 |
Refer to the supplied dimension chart.
APPLICATIONS
Applications
Applicable media: the supplied document lists the following fluids. Actual compatibility depends on selected materials, concentration, temperature, pressure and the specific service conditions.
Application – Water Circulation
Cooling water, circulating water, drinking water and neutral purified water.
Application – Steam Piping
Clean, low-temperature saturated steam, subject to the product’s confirmed temperature and pressure limits.
Application – Compressed Air
Compressed air and nitrogen; verify compatibility for each system.
PURCHASING SUPPORT
Frequently Asked Questions
Find answers to common questions about sizing, materials, threaded connections and operating conditions.
1、What is Union Conical M/F?
It is a 3-piece threaded union with conical sealing seat. One end is male external thread, the other end is female internal thread. Sealing is achieved by metal taper face contact when tightening the hex nut, it does not rely on a PTFE gasket. It allows easy disassembly for pipeline maintenance.
Important distinction:
✅ Union Conical M/F: Metal conical taper seal, M×F thread, gasket-free
✅ Union Flat PTFE MF: Flat face + PTFE gasket seal, M×F thread
These two sealing structures cannot be matched together.
2、What thread standards are available?
We support NPT (ASME B1.20.1), BSPT (R/Rc, EN10226), BSPP (G, ISO228-1).
Threads are NOT interchangeable. Please confirm thread standard and size before order.
3、What stainless steel grades can you supply?
Standard grades:
– 304 / CF8 for water, air and general low-corrosion service
– 316 / 316L / CF8M for coastal, brine, chemical and chloride-containing media
4、What standards and pressure rating?
Cast version follows ISO4144 / MSS SP-114, Class 150LB (PN16).
Forged bar machined version complies with ASME B16.11, available in 3000LB / 6000LB.
Conical metal-to-metal sealing can suit higher temperature service compared with PTFE gasket type. Pressure rating depends on material, wall thickness and production process.
5、Manufacturing process: casting or bar stock machined?
Standard stock items: lost wax investment casting.
High-pressure, high-precision requirement: solid bar CNC machined, higher cost.
7、Can you provide MTC material certificate?
Yes, EN10204 3.1 MTC with heat number is available. EN10204 3.2 third-party certificate can be arranged at buyer’s extra cost.
8、Surface finish options?
Standard: pickled matte finish.
9、Can you do laser marking?
Yes. We can mark size, grade, heat number, customer logo or brand on the flats.
10、Packaging for sea shipment?
Male threads are protected by plastic thread caps. Packed into export cartons, then loaded on fumigated wooden pallets with waterproof stretch film to avoid scratch and thread damage.
11、What is the lead time?
Typically, shipments are dispatched within 7–15 days of receiving the deposit, depending on the order quantity.
12、How is quality controlled?
Raw material inspection → CNC machining → Thread inspection → Hydrostatic testing → Visual inspection → Final dimensional verification before packaging.
13、Which Incoterms are available for overseas buyers?
We offer FOB (Free On Board) terms, with the shipment originating from a Chinese port. We will provide a commercial invoice, packing list, and bill of lading for import customs clearance.
14、Which Incoterms are available for buyers?
We offer FOB (Free On Board) or CIF (Cost, Insurance, and Freight) terms, with shipments originating from a Chinese port. We will provide a commercial invoice, packing list, and bill of lading for customs clearance.
15、What should be done if the threads are found to be defective or do not meet requirements upon arrival?
Please provide photos, videos, and inspection records. We will assess the root cause; depending on the contractual terms, solutions may include product replacement, a partial refund, or a reshipment.”
Union Conical M/F
**304 Stainless Steel Conical-Seat Union (Male Thread × Female Thread), Metal-to-Metal Conical Sealing, PN16 150LB, Compliant with ISO 4144 Standard**
A three-piece union featuring a conical-seat design with male and female threaded connections. The product utilizes a gasketless, metal-to-metal conical seal, making it suitable for high-temperature applications; it also facilitates quick disassembly for pipeline maintenance. Constructed from 304 stainless steel, it offers excellent corrosion resistance and is ideal for use in industrial piping systems. Material Test Certificates (MTC) are available.
Type: Union Conical M/F
Material: 304/316L stainless steel
Nominal diameter: 1/4”–2-1/2” (D8–DN65)
Rated pressure: 150LB
Connection type: Threaded connection (BSPT / BSPP / NPT)
