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S31803 S32205

Can UNS S32205 instead of UNS S31803?

S31803 S32205

The duplex steel UNS S31803

S31803 belongs to duplex steel. With medium strength to high strength and good resistance to common corrosion/stress, corrosion/cracking.

Duplex Steel is about half of ferrite and austenite in its solid solution structure. In the case of low carbon, the chromium content is 18-28%, and the nickel content is 3-10%. Some Duplex Steel s are still Containing alloying elements such as molybdenum, copper, niobium, titanium, nitrogen, Duplex Steel has the characteristics of austenitic and ferritic stainless steel, compared with ferrite, higher plasticity and toughness, no room temperature brittleness, resistance to intergranular corrosion High performance and welding performance, ferritic stainless steel has the brittleness of 475 degrees Celsius and high conductivity coefficient, and has the characteristics of super plasticity. Compared with austenitic stainless steel, Duplex Steel has higher strength, significantly improved resistance to intergranular corrosion and chloride stress corrosion. Duplex steel has excellent pitting corrosion resistance and is a nickel-saving stainless steel. Mainly used in sour oil and gas well production.

The alloy has the ability to resist chloride environment and sulfide stress corrosion, and the strength is about twice that of standard austenitic stainless steel. When higher mechanical strength/lighter weight is required, this alloy can be successfully used as a substitute for 300 series austenitic stainless steel. F51 is easy to use many standard arc welding equipment for welding, but it is not recommended for oxyethylene block welding, because the carbon increase of the weld metal may occur.

UNS S31803 Mechanical properties:

Tensile strength:≥620Mpa
yield strength≥450Mpa
elongation:≥35%,
hardness ≤290 (HB)

The chemical composition of S31803

S31803

The main purpose of UNS S31803 Duplex Steel: (Application field)

• Pressure vessels, high-pressure storage tanks, high-pressure pipes, heat exchangers (chemical processing industry).

• Oil and gas pipelines, heat exchanger fittings.

• Sewage treatment system.

• Pulp and paper industry classifiers, bleaching equipment, storage and processing systems.

• Rotary shafts, press rolls, blades, impellers, etc. under high-strength and corrosion-resistant environments.

• Cargo boxes of ships or trucks

• Food processing equipment

High pressure piping

The content of chromium, molybdenum and nitrogen in UNS S31803 duplex stainless steel makes it highly resistant to pitting and crevice corrosion in oxidizing and acidic solutions.

Anti-corrosion fatigue

The high strength and corrosion resistance of UNS S31803 Duplex Steel make it have high corrosion fatigue strength. Processing equipment is susceptible to corrosive environments and loading cycles. The characteristics of UNS S31803 are very suitable for such applications.

The duplex steel UNS S32205

The yield strength of UNS S32205 duplex stainless steel is twice that of austenitic stainless steel. This feature enables designers to reduce weight when designing products, giving this alloy a more price advantage than 316 and 317L. This alloy is especially suitable for the temperature range of -50°F/+600°F. For applications beyond this temperature range, this alloy can also be considered, but there are some limitations, especially when applied to welded structures.

UNS S32205 chemical composition:

S32205

UNS S32205 physical properties:

UNS S32205 Duplex Steel density: 7.98g/cm3, melting point: 1300-1390 ℃

UNS S32205 heat treatment: heat preservation between 1000-1050℃ for 1-2 hours, rapid air cooling or water cooling

UNS S32205 mechanical properties:
Tensile strength: σb≥795Mpa, yield strength σb≥550Mpa: elongation: δ≥15%, hardness ≤310 (HB)

Due to the chromium content (22%), molybdenum (3%) and nitrogen content (0.18%), the corrosion resistance of UNS S32205 is better than that of 316L and 317L in most environments.

Local corrosion resistance

The content of chromium, molybdenum and nitrogen in UNS S32205 duplex stainless steel makes it highly resistant to pitting and crevice corrosion in oxidizing and acidic solutions.

Stress corrosion resistance

The duplex microstructure of stainless steel helps to improve the stress corrosion cracking resistance of stainless steel. In the presence of a certain temperature, strain, oxygen and chloride, austenitic stainless steel will undergo chloride stress corrosion. Because these conditions are not easy to control, the use of 304L, 316L and 317L is limited in this regard.

Anti-corrosion fatigue

The high strength and corrosion resistance of UNS S32205 duplex steel make it have high corrosion fatigue strength. Processing equipment is susceptible to corrosive environments and loading cycles, and the characteristics of UNS S32205 are very suitable for such applications.

UNS S32205 corrosion resistance and main use environment:

Compared with 316L and 317L austenitic stainless steel, 2205 duplex stainless steel 2205 alloy has superior performance in resistance to pitting corrosion and crevice corrosion. It has high corrosion resistance. Compared with austenitic, its The coefficient of thermal expansion is lower and the thermal conductivity is higher. Compared with austenitic stainless steel, duplex stainless steel 2205 alloy has twice its compressive strength. Compared with 316L and 317L, the designer can reduce its weight. Alloy 2205 is especially suitable for the temperature range of -50°F/+600°F, and can also be used at lower temperatures under strict restrictions (especially for welded structures).

UNS S32205 supporting welding materials and welding technology:

ER2209 welding wire and E2209 welding rod are used for the welding of UNS S32205 duplex steel.

UNS S32205 application areas :

Oil and gas industry equipment;

Offshore platforms, heat exchangers, underwater equipment, fire fighting equipment;

Chemical processing industry, utensils and pipeline industry;

Desalination, high-pressure RO equipment and submarine pipelines;

Energy industry such as power plant desulfurization and denitration FGD system, industrial scrubbing system, absorption tower;

Mechanical parts (high-strength, corrosion-resistant, wear-resistant parts).

Offshore platform

Can UNS S32205 instead of UNS S31803 ?

The conclusion drawn from the comparison of chemical composition and mechanical properties above is that UNS S32205 is better than UNS S31803, so in any application, UNS S32205 can instead of UNS S31803. On the other hand, UNS S31803 can instead of UNS S32205 in general use. In some specific fields , UNS S31803 cannot instead of UNS S32205.

Is there any difference in the prices of S31803 and S32205?

Yes, the price of UNS S32205 is slightly more expensive than UNS S31803, but the difference is not much, about $50-100 per ton. In the actual market, UNS S31803 materials are generally required, and suppliers provide higher-quality UNS S32205 instead. Unless there is a large quantity of UNS S31803 to order, only UNS S31803 materials with preferential prices will be provided.

Best price for S31803 and S32205

We can provide seamless pipes of UNS S32205 and UNS S31803 duplex steel, as well as flanged pipe fittings. If you have any projects of S31803 or S32205, please send your requirements. 

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