Socket Weld Cap (304/304L, 316/316L, 321)

**Product Name:** Stainless Steel Pipe Cap / Butt Weld Cap / Threaded Cap / Socket Weld Cap (304/304L, 316/316L, 321)

The stainless steel pipe cap is a pipe fitting used to close the end of a pipeline, providing a permanent or removable seal. It is available in butt weld (beveled end), threaded, and socket weld configurations. The cap is manufactured from stainless steel grades such as 304/304L, 316/316L, and 321, offering excellent corrosion resistance and reliable sealing in demanding environments. Butt weld caps are formed with a domed or ellipsoidal head and beveled ends for welding directly to the pipe; threaded and socket weld caps are used for smaller-diameter or low-pressure connections.

• Material: Stainless Steel 304/304L, 316/316L, 321 (ASTM A403 WP304/WP316, etc.)
• Nominal Size: 1/2” – 24” (DN15 – DN600) seamless; larger sizes available in welded construction
• Wall Thickness / Schedule: SCH10S, SCH40S, SCH80S, SCH160, XXS
• Type: Butt Weld Cap / Threaded Cap / Socket Weld Cap
• Connection: Butt Weld (Beveled End) / Threaded (NPT, BSP, BSPT) / Socket Weld
• Standards: ASME B16.9, ASME B16.11, ASTM A403, MSS SP-43
• Surface Treatment: Pickled, passivated, or anti-rust oil
• Head Type: Domed / Ellipsoidal

• Petroleum and chemical processing pipelines
• Natural gas transmission and distribution systems
• Power generation and nuclear energy facilities
• Shipbuilding and offshore engineering
• Water treatment and municipal construction
• Food processing and general industrial piping
• Pipeline terminals, testing points, and future expansion connections

• Provides a reliable, leak-resistant seal at pipeline ends
• Excellent corrosion resistance in humid, chemical, and marine environments
• Domed/ellipsoidal head design distributes pressure evenly
• Available in butt weld, threaded, and socket weld configurations for different installation needs
• Smooth surface finish minimizes contamination and flow resistance
• Compatible with standard pipe schedules and welding procedures

• Closes the end of a pipeline or fitting permanently or temporarily
• Seals pipeline terminals, testing points, and reserved branch connections
• Maintains system pressure integrity
• Allows future pipeline extension by removing the cap (threaded or socket weld types)
• Protects pipeline ends from contamination and mechanical damage during storage and transport

• Verify cap type, size, schedule, and material match the pipeline design
• Inspect the cap and beveled/threaded ends for cracks, dents, or deformation before installation
• Clean the pipe end and cap connection surface; remove oil, rust, and debris
• For butt weld caps: align the cap with the pipe, tack-weld at multiple points, then complete butt welding using an approved procedure
• For threaded caps: apply PTFE tape or sealant to the male threads, tighten with a wrench—do not over-torque
• For socket weld caps: insert the pipe into the socket, leave a small expansion gap, then weld per applicable standard
• Perform pressure testing or non-destructive testing as required

• Do not subject the cap to impact or drop during storage and handling
• Keep stainless steel caps away from carbon steel to prevent galvanic corrosion
• Ensure the pipeline is depressurized and drained before installation or removal
• Do not use damaged or deformed caps; inspect for cracks before welding
• Use welding consumables matched to the cap material
• For threaded caps in high-pressure or vibration-prone systems, consider additional sealing or locking measures
• For high-pressure applications, use caps with verified material certificates

• Standard export packing: wooden case or plywood pallet with moisture-proof wrapping
• Dispatch within 3–7 working days for stock items; 15–30 days for customized orders
• Shipping methods: sea freight, air freight, or express courier depending on quantity and destination
• Tracking number provided upon dispatch

• T/T (bank transfer): 30% deposit, 70% balance before shipment
• L/C at sight accepted for larger orders
• PayPal / Western Union for sample orders
• All prices are quoted EXW or FOB unless otherwise specified

• Each cap is wrapped in plastic film or bubble bag
• Multiple pieces are packed in sturdy wooden cases or plywood pallets
• Desiccant is added for sea shipments to prevent moisture
• Beveled ends and threads are protected with covers to prevent damage
• Custom labeling and marking available upon request

• 7-day return or exchange for quality defects (buyer bears return freight unless the defect is verified as our responsibility)
• Custom-made or non-stock items are not eligible for return unless defective
• Warranty period: 12 months from delivery for manufacturing defects
• Claims for shortage or damage must be reported within 3 working days of receipt with photo evidence
• Technical support available for welding procedures, material selection, and installation guidance