Duplex Stainless Steel S31803 is a type of duplex stainless steel that combines the beneficial properties of both austenitic and ferritic stainless steels. This material is known for its excellent corrosion resistance, high strength, and good weldability, making it suitable for a wide range of applications in aggressive environments, such as chemical processing, oil and gas, and marine industries.

Chemical Composition:

The chemical composition of S31803 typically includes:

Chromium (Cr): 21.0% - 23.0%

Nickel (Ni): 4.5% - 6.5%

Molybdenum (Mo): 2.5% - 3.5%

Nitrogen (N): 0.08% - 0.20%

Manganese (Mn): ≤ 2.0%

Silicon (Si): ≤ 1.0%

Carbon (C): ≤ 0.03%

Phosphorus (P): ≤ 0.03%

Sulfur (S): ≤ 0.02%

Iron (Fe): Balance

Mechanical Properties:

Tensile Strength: ≥ 620 MPa

Yield Strength: ≥ 450 MPa

Elongation: ≥ 25%

Hardness: ≤ 290 HB

Forging Process:

The forging process for S31803 involves heating the material to a temperature range of 1100°C to 1200°C (2012°F to 2192°F) and then shaping it into a ring using a forging press or hammer. The process typically includes the following steps:

Heating: The billet or ingot is heated uniformly to the forging temperature.

Preforming: The heated material is preformed into a rough shape.

Forging: The preformed material is forged into the final ring shape using dies.

Heat Treatment: The forged ring is subjected to a solution annealing treatment at 1020°C to 1100°C (1868°F to 2012°F) followed by rapid cooling to achieve the desired microstructure and properties.

Machining: The forged ring is machined to the final dimensions and surface finish.

Applications:

Duplex Stainless Steel S31803 forging rings are used in various applications, including:

Pressure vessels

Heat exchangers

Pumps and valves

Flanges and fittings

Offshore oil and gas equipment

Chemical processing equipment

Advantages:

High corrosion resistance, especially in chloride-containing environments

Excellent mechanical properties, including high strength and toughness

Good weldability and formability

Resistance to stress corrosion cracking

Standards:

ASTM A182/A182M: Standard specification for forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts for high-temperature service.

ASTM A479/A479M: Standard specification for stainless steel bars and shapes for use in boilers and other pressure vessels.

EN 10088-3: Stainless steels - Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections, and bright products of corrosion-resistant steels for general purposes.

Duplex Stainless Steel S31803 forging rings are highly durable components that offer a combination of strength, corrosion resistance, and versatility, making them ideal for demanding industrial applications.