Butt Welding Eccentric Reducer ASTM A815 UNS S31803 Duplex Stainless Steel 10" SCH40 ASME B16.9

Butt Welding Eccentric Reducer ASTM A815 UNS S31803 Duplex Stainless Steel 10" SCH40  ASME B16.9

1. Product Description

This product is a butt-welding eccentric reducer manufactured from UNS S31803 (Duplex 2205) stainless steel in accordance with ASTM A815 and ASME B16.9 standards. UNS S31803 is a dual-phase stainless steel with a microstructure of approximately 50% ferrite and 50% austenite, offering roughly double the yield strength of standard 300-series austenitic stainless steels while maintaining excellent corrosion resistance . An eccentric reducer is a cone-shaped fitting used to connect pipes of different diameters, with the distinctive feature that the centerlines of the larger and smaller ends are offset (not coincident) . This 10" SCH40 fitting is designed for permanent butt-weld connection in demanding industrial piping systems.

2. Key Product Parameters

3. Application / Usage

This eccentric reducer is ideal for high-pressure and corrosive fluid systems in horizontal piping applications:

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

• Chemical Processing: Chloride-containing process streams, acid services, heat exchangers

• Marine & Desalination: Seawater piping systems, reverse osmosis feed lines, brine handling

• Power Generation: Cooling water systems, high-temperature service

• Pulp and Paper: Bleaching lines, digester systems 

4. Advantages

• Superior Strength: Yield strength (450 MPa) is approximately double that of 316L, enabling thinner wall designs and significant weight savings 

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

• Eccentric Design Advantage: Offset centerlines allow installation with "flat side down" to prevent liquid accumulation, or "flat side up" to prevent vapor pockets in horizontal piping 

• Good Weldability: Compatible with standard welding procedures with strict heat input control; solution annealing at 1020-1100°C required post-weld 

• Cost-Effective: Higher strength offsets material cost premium over austenitic grades in critical service

5. Functions

The eccentric reducer provides a permanent, pressure-rated transition between two pipes of different diameters within a piping system. The eccentric configuration features offset centerlines with one side of the pipe wall remaining flat, specifically designed for horizontal pipelines to prevent liquid accumulation at the bottom or air entrapment at the top . For the 10" SCH40 configuration, it serves as a durable inline reducer for critical applications requiring welding.

6. Installation Instructions

1. Unpacking Inspection: Check for transit damage; verify markings, dimensions, and pressure class per ASME B16.9

2. Surface Preparation: Clean the weld bevel and adjacent area using dedicated tools; remove all oil, grease, and contaminants

3. Alignment: For horizontal liquid lines, install with the "flat side" facing down to prevent liquid accumulation; for gas lines, flat side up to prevent vapor pockets

4. Tack Welding: Apply minimum tack welds to hold the fitting in position; clean thoroughly before final welding

5. Welding: Perform butt-weld following approved WPS with certified welders. For duplex materials, strict heat input control is essential. Use matching filler metal (e.g., ER2209). Interpass temperature must be maintained ≤150°C to prevent intermetallic phase formation 

6. Post-Weld Treatment: Solution annealing at 1020-1100°C followed by water quenching is required to restore the duplex structure and corrosion resistance 

7. Inspection: Perform NDT (PT/MT, UT) as per project requirements. Ferrite content verification per ASTM E562 is recommended

7. Precautions

• Temperature Limitation: Not recommended for use above 300°C or below -50°C due to reduced toughness 

• Ferrite Balance: Ensure ferrite content remains between 40-60% . Improper heat treatment is the most common cause of out-of-spec ferrite ratios

• Orientation: Eccentric reducers in horizontal piping must be installed with correct orientation (flat side down for liquids, flat side up for gases) to prevent accumulation issues 

• Intermetallic Phase Sensitivity: Duplex welds are sensitive to sigma phase formation; tight heat input control and rapid post-weld cooling are mandatory 

• Cleanliness: Requires a higher degree of cleanliness than carbon steel fabrication; use dedicated tools to prevent contamination

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 strict quality inspection before shipment, with Mill Test Certificates (EN 10204 3.1/3.2) available

• Mandatory documentation includes chemistry, mechanical properties, ferrite content, and corrosion test results

• Third-party inspection (ABS, DNV, CCS, LR, BV, etc.) available upon request

• 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.