ASME B16.9 Stainless Steel Butt Weld Pipe Cap for Pipeline Sealing End Cap

Product Specification

ASME B16.9 Stainless Steel Butt Weld Pipe Cap for Pipeline Sealing End Cap

1. Product Description

A stainless steel pipe cap is a non‑welded or welded end closure fitting that terminates the open end of a piping system. It is produced from solid stainless steel bars (for threaded and socket‑weld types) or from flat rolled plates (for butt‑weld types) using hot stamping, cold drawing, or forging techniques. The finished cap features a smooth internal transition and a uniform wall profile. Depending on the design pressure and service conditions, the end shape can be a standard elliptical (2:1 ratio), hemispherical (high pressure), dished (shallow), or flat cover (low pressure, non‑critical services). Precision machining ensures that the bevel ends (for butt‑weld) conform to ASME B16.25 with a 37.5° ± 2.5° bevel angle and a 1.6 mm root face, while threaded ends are manufactured to the appropriate gauge tolerance per ASME B1.20.1 (NPT) or ISO 7‑1 (BSPT). Each piece is heat‑treated (where applicable) to relieve residual stresses and optimise grain structure, followed by pickling and passivation to restore the passive chromium oxide layer.

2. Product Applications

• As a permanent end closure for main process lines in crude oil refining, natural gas treatment, and chemical synthesis plants.

• As a temporary seal for testing loops (hydrostatic, pneumatic, and leak testing) during construction and commissioning.

• For capping off unused branch connections in utility systems such as steam, condensate, cooling water, and compressed air.

• In high‑purity pharmaceutical and biotechnology applications, where the caps are electropolished and certified for low surface roughness (Ra ≤ 0.4 µm) to prevent product contamination.

• For offshore subsea pipelines, where caps with extra wall thickness and corrosion allowance are required to withstand seawater pressure and cathodic protection effects.

• In high‑temperature furnace piping (e.g., reformer tubes and heat exchanger headers) using heat‑resistant grades like 310S or 253MA.

• As protective covers for pipe ends during module fabrication and pre‑fabrication yard storage.

3. Product Advantages

• Outstanding resistance to pitting and crevice corrosion – especially with 316/316L and duplex grades, making them suitable for chloride‑rich environments.

• Excellent weldability – low carbon content (L‑grades) prevents intergranular corrosion after welding.

• Precision‑machined sealing surfaces – ensure leak‑tight closure under repeated thermal cycling and pressure fluctuations.

• High dimensional consistency – produced under strict quality control, with bevel angles, roundness, and wall thickness tolerances meeting or exceeding standard requirements.

• Versatile grade selection – from standard austenitic to super‑austenitic and duplex steels, covering a wide range of corrosive media and temperatures.

• Traceability – each cap is marked with heat number, material grade, size, and schedule, enabling full material traceability.

• Customizable surface finish – available in mill finish, pickled and passivated, or mechanically polished to mirror finish (Ra ≤ 0.8 µm for sanitary use).

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​4.Key Specifications

FAQ

1. Are you trading company or manufacturer ? We are manufacturer ,You can see the certification.

2.How long is your delivery time? Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.

3. Do you provide samples ? is it free or extra ? Yes, we could offer the sample for free charge but need pay the cost of freight.

4. What is your terms of payment ? Payment<=1000USD, 100% in advance. Payment>=1000USD, 50% T/T in advance ,balance before shippment.