Machuca Fittings, located in Kuala Lumpur, Malaysia, stands out as a top manufacturer and supplier of Duplex Steel UNS S31803 Forged Fittings. They provide high-quality, durable solutions tailored for demanding industrial applications. Their impressive product lineup features forged elbows, tees, couplings, unions, and plugs, all designed to ensure leak-proof connections, robust mechanical strength, and long-lasting reliability. UNS S31803, a popular duplex stainless steel grade, merges austenitic and ferritic microstructures, offering remarkable resistance to pitting, crevice corrosion, and stress corrosion cracking, all while maintaining excellent tensile and yield strength. Machuca Fittings guarantees that their S31803 forged fittings comply with international standards across various sectors, including chemical, petrochemical, marine, oil & gas, and power generation.
| Size | : | 1/2″NB TO 4″NB IN |
| Standard | : | ASTM A182 / ASME SA182 |
| Dimensions | : | ANSI/ASME B16.11 & BS3799, etc. |
| Grade | : | UNS S31803, S32205, S2205, S32550, S32750, S32760. |
| Class | : | 2000LBS, 3000LBS, 6000LBS, 9000LBS, etc. |
The Duplex Steel UNS S31803 Forged Fittings are made up of about 22% chromium, 5–6% nickel, 3% molybdenum, 0.14–0.20% nitrogen, along with trace amounts of manganese, silicon, and carbon. This unique composition delivers outstanding corrosion resistance in environments rich in chlorides and oxidizing agents, while also ensuring high mechanical strength. The dual-phase microstructure provides excellent toughness, ductility, and stability when faced with thermal and mechanical stress. Thanks to their strong weldability, formability, and durability, S31803 forged fittings are reliable even in high-pressure, high-temperature, and chemically aggressive conditions.
| UNS S31803 | Ni | Cr | Mo | Mn | Si | C | N | S | P | Fe |
| min | 4.5 | 22.0 | 3.0 | – | – | – | 0.14 | – | – | – |
| max | 6.5 | 23.0 | 3.5 | 2.0 | 1.0 | 0.03 | 0.2 | 0.02 | 0.03 | Balance |
| Grade | S31803 |
| Density (g/cm 3) | 7.805 |
| Density (lb/in 3) | 0.285 |
| Melting Point (°C) | 1420 – 1465 |
| Melting Point (°F) | 2588 – 2669; |
Machuca Fittings is a leading supplier of Duplex Steel UNS S31803 Forged Fittings in Kuala lumpur, Malaysia. We offer an extensive range of Duplex Steel UNS S31803 Forged Fittings, renowned for their excellent corrosion resistance and high strength, which makes them perfect for demanding industrial applications like chemical processing, marine environments, and high-temperature systems. With a commitment to quality and reliable delivery, we ensure our clients receive top-tier products tailored to meet the specific needs of various industries.
We provide products that come with both mill test certificates and third-party test certificates, ensuring the highest standards of quality and compliance.
Choose Duplex Steel UNS S31803 Forged Fittings from Machuca Fittings for superior quality, exceptional corrosion resistance, and reliable performance in extreme conditions. We offer customized solutions backed by expert support and industry experience.
Duplex Steel UNS S31803 Forged Fittings offer numerous advantages, including exceptional corrosion resistance, especially in chloride-rich environments, making them ideal for industries such as oil and gas, chemical processing, and marine. Their unique duplex structure provides high strength, excellent resistance to stress corrosion cracking, and superior fatigue resistance. These fittings also exhibit excellent weldability, ensuring easy installation and maintenance. With impressive toughness and the ability to withstand high-pressure and high-temperature conditions, Duplex Steel UNS S31803 Forged Fittings deliver long-lasting durability and reliable performance in critical applications.
Yes, custom sizes for Duplex Steel UNS S31803 Forged Fittings are available at Machuca Fittings. We offer tailored solutions to meet your specific requirements, ensuring optimal performance for your projects. For more information, please contact us at sales@machucafittings.com.
| STANDARD | UNS | |
| Duplex Steel Forged Fittings | S31803 / S32205 |
| DN-NPT | MAJOR DIAMETER MM | TAPPING /DRILL SIZE MM | TPI | PITCH MM |
|---|---|---|---|---|
| 1/16″ | 7.895 | 6.00 | 27 | 0.941 |
| 1/8″ | 10.242 | 8.25 | 27 | 0.941 |
| 1/4″ | 13.616 | 10.70 | 18 | 1.411 |
| 3/8″ | 17.055 | 14.10 | 18 | 1.411 |
| 1/2″ | 21.223 | 17.40 | 14 | 1.814 |
| 3/4″ | 26.568 | 22.60 | 14 | 1.814 |
| 1″ | 33.228 | 28.50 | 11.5 | 2.209 |
| 1¼” | 41.985 | 37.00 | 11.5 | 2.209 |
| 1½” | 48.054 | 43.50 | 11.5 | 2.209 |
| 2″ | 60.092 | 55.00 | 11.5 | 2.209 |
| 2½” | 72.699 | 65.50 | 8 | 3.175 |
| 3″ | 88.608 | 81.50 | 8 | 3.175 |
| 3½” | 101.316 | 94.30 | 8 | 3.175 |
| 4″ | 113.973 | 107.00 | 8 | 3.175 |
| 5″ | 141.300 | 134.384 | 8 | 3.175 |
| 6″ | 168.275 | 161.191 | 8 | 3.175 |
| 8″ | 219.075 | 211.673 | 8 | 3.175 |
| 10″ | 273.050 | 265.311 | 8 | 3.175 |
| 12″ | 323.850 | 315.793 | 8 | 3.175 |
| Description | Class Designation | ||
|---|---|---|---|
| 3000 | 6000 | 9000 | |
| Elbows 45 and 90 degrees, Tees, Crosses, Couplings, Half-Couplings, End or Pipe Caps | 1/2 – 4 | 1/2 – 2 | 1/2 – 2 |
| 1/2 – 4 | 1/2 – 2 | 1/2 – 2 | |
| 1/2 – 4 | 1/2 – 2 | 1/2 – 2 | |
| Pipe Size by Wall Thickness | SCH 80 / XS | SCH 160 | XXS |
These Duplex Steel UNS S31803 Forged Fittings find extensive use in industries that demand high strength, corrosion resistance, and long-lasting durability. In chemical and petrochemical plants, they are essential for piping systems that transport acids, alkalis, chlorides, and other aggressive chemicals. The oil and gas sector relies on them for refineries, offshore platforms, and subsea pipelines. Their exceptional seawater resistance makes them ideal for marine applications, while power generation facilities utilize them in heat exchangers, boilers, and high-temperature piping systems. Their blend of mechanical strength and durability makes them a go-to choice for various challenging environments.
Get in touch with one of our Technical Sales Representatives to request a quote or get answers to any questions you may have.








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