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Uns S31803 Sheet

UNS S31803 sheet is a duplex stainless steel material with a balanced austenite-ferrite structure, offering excellent strength and corrosion resistance. Its high chromium, molybdenum, and nitrogen content make it ideal for marine, chemical, and offshore applications where durability and reliability are critical.

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Uns S31803 Sheet

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Stainless Steel Strips

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Product Details

UNS S31803 sheet is a duplex stainless steel material that combines austenitic and ferritic microstructures. It is widely used in applications requiring high strength and excellent resistance to corrosion, especially in chloride-rich and marine environments.

Compared with standard stainless steels such as 304 and 316L, UNS S31803 offers significantly higher mechanical strength and improved resistance to stress corrosion cracking.

Chemical Composition of UNS S31803

The performance of UNS S31803 sheet is based on its balanced dual-phase alloy system.

Typical chemical composition:

Element	Content Range	Function
Chromium (Cr)	21.0 – 23.0%	Provides strong corrosion resistance
Nickel (Ni)	4.5 – 6.5%	Stabilizes duplex structure
Molybdenum (Mo)	2.5 – 3.5%	Enhances pitting and crevice corrosion resistance
Nitrogen (N)	0.08 – 0.20%	Improves strength and corrosion resistance
Carbon (C)	≤ 0.03%	Maintains corrosion stability
Manganese (Mn)	≤ 2.0%	Improves hot working performance
Silicon (Si)	≤ 1.0%	Enhances oxidation resistance
Iron (Fe)	Balance	Base metal

The combination of high chromium, molybdenum, and nitrogen is the key factor behind its superior performance.

Key Characteristics of UNS S31803 Sheet

UNS S31803 sheet has a dual-phase microstructure consisting of approximately equal proportions of austenite and ferrite. This structure provides a balance of strength and corrosion resistance.

It offers high tensile strength, excellent resistance to chloride-induced corrosion, and strong resistance to stress corrosion cracking.

Mechanical Properties of UNS S31803

UNS S31803 sheet has significantly higher mechanical strength than conventional austenitic stainless steels.

It typically provides:

Higher yield strength compared with 304 and 316L
Good toughness under low-temperature conditions
Strong fatigue resistance
Excellent load-bearing capacity

This makes it suitable for structural and high-stress applications.

Corrosion Resistance Performance

UNS S31803 sheet offers excellent corrosion resistance in aggressive environments.

It performs particularly well in:

Seawater and marine environments
Chemical processing systems
Chloride-rich industrial environments
Offshore oil and gas applications

Its high chromium and molybdenum content significantly improves resistance to pitting and crevice corrosion.

Heat Resistance and Stability

UNS S31803 sheet maintains good stability under moderate temperature conditions. However, it is primarily designed for corrosion resistance rather than high-temperature service.

Prolonged exposure to very high temperatures may affect its microstructure and performance.

Processing Characteristics

UNS S31803 sheet has good weldability and moderate formability. However, due to its higher strength, it requires more forming force compared with austenitic stainless steels.

Proper welding procedures are important to maintain corrosion resistance and mechanical balance.