Forged Socket Welding Coupling ASTM A182 UNS S31803 Duplex Stainless Steel DN20

Product Specification

Forged Socket Welding Coupling ASTM A182 UNS S31803 Duplex Stainless Steel DN20 ASME B16.11

1. Product Description

This product is a forged socket welding coupling manufactured from ASTM A182 UNS S31803 in accordance with ASME B16.11 standards . A coupling is a fundamental fitting used to join two sections of pipe in a straight line . The socket weld (SW) connection involves inserting the pipe into the fitting's socket and applying a fillet weld around the joint . Duplex 2205 is a dual-phase stainless steel with roughly equal proportions of austenite and ferrite, offering roughly double the yield strength of standard 300-series austenitic stainless steels and exceptional corrosion resistance . This DN20 (3/4") Class 3000# fitting is designed for permanent, leak-proof connections in demanding small-bore piping systems.

2. Key Product Parameters

3. Application / Usage

This socket weld coupling is ideal for high-pressure and corrosive service:

• Oil & Gas: Offshore platforms, subsea piping, high-pressure process lines 

• Chemical Processing: Chloride-containing acids, brine services 

• Desalination: High-pressure reverse osmosis piping connections 

• Marine & Seawater Systems: Fire water, cooling water systems 

• Instrumentation: Connections requiring leak-proof integrity 

4. Advantages

• Superior Strength: Yield strength is approximately double that of 316L austenitic steel, enabling thinner wall designs 

• Excellent Corrosion Resistance: PREN ~34-36 provides outstanding resistance to pitting, crevice corrosion, and chloride stress corrosion cracking 

• Leak-Proof Connection: Socket weld with fillet weld provides high leak resistance, ideal for flammable, toxic, or high-pressure fluids 

• Vibration Resistance: Excellent performance on lines subject to vibration and thermal cycling 

• Cost-Effective: Higher strength offsets per-kilogram cost premium over 316L 

5. Functions

The socket weld coupling joins two sections of small-bore pipe (NPS 2 or smaller) in a straight line . It provides a permanent, pressure-rated, leak-proof joint for piping system extension or repair . For DN20 (3/4") Class 3000#, it serves as a durable inline connection for critical service applications requiring welding.

6. Installation Instructions

1. Preparation: Clean pipe ends and coupling socket of all contaminants

2. Expansion Gap: Insert pipe leaving 1/16" (1.6 mm) gap between pipe end and socket bottom before welding 

3. Welding: Perform fillet weld around the joint using qualified WPS and certified welders

4. NDT: Visual and PT/MT examination recommended for fillet weld 

5. Cleaning: Post-weld cleaning and inspection as per procedure

7. Precautions

• Expansion Gap: The 1/16" gap is mandatory to prevent thermal expansion cracking 

• Temperature Limitation: Maximum service temperature ~315°C (600°F) 

• Ferrite Balance: Heat treatment (solution anneal) required to maintain 40-60% ferrite content 

• Quality Testing: Ferric chloride pitting test per ASTM A923 Method C recommended 

• NACE Compliance: Hardness below 28 HRC required for sour gas service 

8. Shipping & Delivery

• Standard delivery time is typically 15–30 days, subject to order quantity and specification availability.

9. Payment Terms

• Common international payment methods include T/T (Telegraphic Transfer) and L/C at sight (Letter of Credit) .

10. Packaging

• Products are securely packed in plywood cases or wooden crates with internal cushioning to ensure safe transportation and prevent damage during transit .

11. After-Sales / Return & Warranty Policy

• All products undergo 100% strict quality inspection before shipment, with Mill Test Certificates (EN 10204 3.1/3.2) available .

• In case of quality issues, retain original packaging and provide relevant photos or third-party inspection reports.

• Specific return, exchange, and warranty terms are subject to the final sales contract agreement.

  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.