PRODUCT FEATURES
Threaded Cap — Product Features
Suitable for water treatment, piping systems, mechanical piping, fire protection systems, light chemical processing, food processing equipment, pump and valve manifolds, sealing unused branch ports, and temporary sealing during hydrostatic testing.
Product Feature
Buyer Information
Product Feature
EN 10204 3.1 material inspection certificates are available for bulk orders. Custom OEM branding is accepted. Samples can be provided for quality verification prior to mass production. Please carefully verify thread types and dimensions before production to avoid installation mismatches on-site.
OPERATING PRINCIPLE
How Threaded Cap Works
1. Circular body with internal threads: Features a smooth, round exterior and internal threading, allowing it to screw onto externally threaded pipe ends to create a seal.
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2. Fully forged construction
Dense material structure free from porosity or sand holes; offers high mechanical strength suitable for high-pressure applications.
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3. 304 Stainless Steel
Provides excellent corrosion resistance against moisture, fresh water, and mildly corrosive media.
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4. Precision-machined threads
Available with NPT or BSPT threads; ensures a tight fit, reliable sealing, and ease of assembly/disassembly.
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5. Pressure ratings
150LB/3000LB; compliant with MSS SP-83 and ASME B16.11 standards.
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6. Pickled and passivated finish
Clean surface with rust-resistant properties and a long service life.
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7. Comprehensive size range
1/8″ to 4″ (DN6 to DN100); supports custom marking.
ENGINEERING DATA
Technical Specifications
Technical data supplied for Threaded Cap. Ratings and material combinations should be confirmed for the selected configuration.
| PARAMETER | SPECIFICATION |
|---|---|
| – Material | AISI 304 (ASTM A182 F304) |
| – Type | Round female threaded cap |
| – Thread Standard | NPT (ANSI B1.20.1) / BSPT (BS EN 10226-1) |
| – Pressure Rating | 150LB / 3000LB |
| – Manufacturing Standard | MSS SP-83, ASME B16.11 |
| – Surface Treatment | Pickling and passivation |
| – Operating Temperature | -20°C to +120°C |
MECHANICAL DIMENSIONS
Dimensions & drawings.
Compare connection size with the corresponding overall length, bore and handle clearance dimensions from the supplied drawing.
Dimension chart
| SIZE | φ3 | φ4 | A | B | D |
|---|---|---|---|---|---|
| 1/4 | 16 | 18 | 18 | 6 | 15 |
| 3/8 | 18 | 20.5 | 18 | 6 | 16 |
| 1/2 | 23.5 | 26 | 20 | 6 | 18 |
| 3/4 | 29 | 31.5 | 22 | 7 | 20 |
| 1 | 36 | 39 | 22.5 | 7 | 20 |
| 11/4 | 45 | 49 | 25 | 7 | 22.5 |
| 11/2 | 52 | 54 | 26 | 8 | 23 |
| 2 | 64 | 67 | 32 | 11 | 29.5 |
| 21/2 | 80 | 84 | 39 | 12 | 35 |
| 3 | 93 | 96 | 42 | 14 | 39 |
| 4 | 120 | 125 | 48 | 15 | 44 |
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.
What is a 304 threaded round pipe cap?
Answer: This is a stainless steel pipe fitting featuring internal threads and a smooth, round exterior cap. It is used to seal or plug the threaded ends of pipes, allowing for either temporary or permanent closure of a piping system. It is also referred to as an SS304 round pipe cap or a threaded blind cap.
What is the material grade? Can a Material Test Report (MTR) be provided?
Answer: The standard material is AISI 304 (ASTM A182 F304 / CF8). A Material Test Report (MTR) can be provided upon request. Other available material grades include 304L, 316L, and 316.
What material grades are available?
Answer: Stainless steel grades: ASTM A182 F304 / F304L / F316 / F316L.
All raw materials are supplied with a Material Test Certificate (MTC) and a Positive Material Identification (PMI) report to meet the buyer’s traceability requirements.
What are the pressure ratings/working pressures?
Answer: Standard 304 threaded pipe caps are typically classified as Class 150 or Class 3000; the maximum working pressure varies depending on the temperature. Every batch of products undergoes hydrostatic testing.
Which thread standards are supported?
BSPT, BSPP (G), or NPT standards are supported. Please specify the required thread type when placing an order.
What is the size range?
1/8 inch to 4 inches.
What documents and certificates are available for customs clearance and on-site inspection?
Answer:
– MTC (Material Test Certificate, for ASTM material traceability)
– PMI (Positive Material Identification report)
(These documents must be requested in advance; additional costs may apply, and lead times may be extended.)
What surface finishes are available?
Answer: The standard finish is a pickled matte surface. Other options include a satin finish or a mirror-polished finish suitable for sanitary/hygienic applications.
Why might a leak occur after installation? A: Primary causes:
1. Mismatched thread standards (e.g., mixing NPT and BSP standards).
2. Damaged threads or the presence of burrs.
3. Insufficient application of PTFE sealing tape (thread seal tape).
4. Overtightening, leading to thread galling (seizing).
It is recommended to wrap 2–3 layers of PTFE sealing tape before installation.
What is the Minimum Order Quantity (MOQ)?
Small-batch orders are accepted, and a single order may include products of different specifications.
What is the lead time?
Typically, shipments are dispatched within 7–15 days of receiving the deposit, depending on the order quantity.
How is quality controlled?
Raw material inspection → CNC machining → Thread inspection → Hydrostatic testing → Visual inspection → Final dimensional verification before packaging.
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.
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.
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.
Threaded Cap
304 Stainless Steel Cast/Forged Round Female Threaded Pipe Cap (Pressure Ratings: 150LB/3000LB; Thread Options: NPT or BSPT)
This SS304 forged/cast round pipe cap is designed to seal the ends of male-threaded pipes, providing a permanent seal or a closure for pressure testing. Featuring a compact round profile, precision internal threads, and excellent corrosion resistance, it is widely used in industrial and water piping systems. Material Test Certificates (MTC) are available.
Type: Threaded Cap
Material: 304/316L stainless steel
Nominal diameter: 1/4”–2” (D8–DN50)
Rated pressure: 150LB/3000LB
Connection type: Threaded connection (BSPT / BSPP / NPT)
