ASME SA403 WP304-S Stainless Steel Butt Weld End Cap with ASME B16.9 Dimensional Standard

The ASME SA403 WP304-S Stainless Steel Butt Weld End Cap is a 304-series austenitic stainless steel pipe fitting designed to close the end of a piping run through a butt-weld connection.

The fitting is manufactured for dimensional compatibility with ASME B16.9 butt-weld fittings and can be supplied in different nominal sizes and wall thickness configurations. Its compact geometry makes it suitable for pipe-end closure where a welded connection is preferred over a threaded or flanged termination.

The WP304-S material designation is particularly suitable for general stainless steel process piping where corrosion resistance, weldability and fabrication compatibility are required.

WP304-S belongs to the 304 family of austenitic stainless steel fitting materials and is intended for fabricated pressure-piping components.

The material combines chromium and nickel alloying with austenitic metallurgical structure, providing a useful balance of corrosion resistance, ductility and weldability for general process piping.

For actual service selection, the operating medium, temperature, chloride exposure and welding conditions should be considered rather than selecting the fitting solely by material name.

Unlike an ordinary flat closure plate, a butt weld end cap is formed with a curved end profile. This geometry provides a gradual transition from the pipe wall toward the closed end of the fitting.

Important dimensional characteristics include:

• Outside Diameter
• Overall Height
• Wall Thickness
• End Bevel
• Inside Profile
• Crown Radius
• Straight Length
• Pipe Matching Diameter

These dimensions are controlled according to the applicable fitting standard and project requirements.

The cap is installed directly onto the pipe end and joined by welding. The butt-weld configuration provides:

• Permanent pipe closure
• Compact connection geometry
• Smooth external profile
• No threaded engagement
• Suitable integration with welded piping systems

The end preparation can be supplied according to the applicable dimensional standard and welding procedure.

The product can be used for pipe-end closure in:

• Chemical Process Piping
• General Industrial Piping
• Petrochemical Systems
• Water Treatment Piping
• Food Processing Lines
• Pharmaceutical Utilities
• Gas Piping
• Utility Piping
• Stainless Steel Process Lines
• Equipment Connection Piping

• Process Piping
• Storage Tanks
• Process Skids
• Chemical Equipment
• Piping Manifolds
• Utility Systems
• Stainless Steel Equipment
• Pressure Piping Assemblies

• Welded Pipe-End Closure: The cap creates a permanent closure without introducing threads or additional flange components.
• Compact Profile: The formed cap geometry occupies relatively little installation space compared with some mechanical closure arrangements.
• Stainless Steel Construction: 304-series stainless steel is suitable for a broad range of general corrosive and sanitary-adjacent industrial environments.
• Dimensional Compatibility: Manufacturing to the applicable ASME B16.9 dimensional requirements allows the fitting to be integrated with compatible butt-weld piping components.
• Custom Manufacturing: Size, wall thickness, surface finish and inspection requirements can be adjusted according to project specifications.

A typical production route may include:

1. Stainless Steel Material Preparation
2. Cutting / Blank Preparation
3. Forming
4. Heat Treatment
5. End Preparation
6. Sizing
7. Surface Treatment
8. Dimensional Inspection
9. PMI
10. NDT Where Required
11. Marking
12. Final Inspection

The exact manufacturing route depends on the size, wall thickness and production method.

Available inspection items include:

• Chemical Composition
• Mechanical Properties
• Dimensional Inspection
• Wall Thickness Measurement
• End Diameter Inspection
• Visual Examination
• Surface Inspection
• PMI
• Liquid Penetrant Testing
• Ultrasonic Testing Where Required

Material and inspection documentation can be supplied according to the purchase specification.

Note: Exact equivalence should be confirmed against the applicable material specification and product form rather than treating all 304 designations as automatically interchangeable.

What is an SA403 WP304-S end cap?
It is a stainless steel butt-weld fitting used to permanently close the end of a compatible pipe.

What standard is used for its dimensions?
The fitting can be manufactured according to ASME B16.9 dimensional requirements.

What does WP304-S mean?
WP304-S identifies a 304-series austenitic stainless steel fitting material under the SA403 specification.

Is this an end cap or pipe cap?
For industrial piping terminology, butt weld end cap, butt weld cap, and pipe cap can refer to this type of welded pipe-end closure. For SEO, we recommend using Butt Weld End Cap as the primary term and Stainless Steel Pipe Cap as a secondary keyword.