2205 dual phase steel: S31803, F51, 1.4462; Material brand: 2205 duplex steel, American brand: UNS S31803, German brand: 1.4462, Chinese brand: 00Cr22Ni5Mo3N, F51, S32205;

Executive Standards for 2205 duplex steel production: ASTM a 959-2004, ASTM a240 / 240m-2018, ASTM a313 / a313m-2018, ASTM a270 / a270m-2015, ASTM a1082 / a1082m-2016, ASTM a554-2016, ASTM a240 / a240m-2020, ASTM a959-2019, ASTM a313 / a313m-2018, ASTM a 959-2004, SAE j405-1998, ASTM A182 / a182m-2018, ASTM a240 / 240m-2018, ASTM a276 / a276m-2017, SAE j405-2018 ASTM A313/A313M-2018、ASTM A270/A270M-2015、ASTM A1082/A1082M-2016、ASTM A511/A511M-2020、ASTM A554-2016、ASTM A240/A240M-2020、ASTM A959-2019、GB /T 20878-2007、GB /T 1220-2007、GB /T 3280-2015、GB /T 4237-2015、GB /T 12770-2012、GB /T 4356-2016、GB /T 4240-2019、ASTM A313/A313M-2018、GB /T 5216-2004、ASTM A182/A182M-2018、 GB /T 3280-2015、GB /T 4237-2015、GB /T 4240-2019；

2205 dual phase steel is a new product successfully researched and developed in 2000. 2205 dual phase steel is a kind of nitrogen added dual phase stainless steel (2205 dual phase steel for short). 2205 dual phase steel is a compound stainless steel composed of 21% chromium, 2.5% molybdenum and 4.5% nickel nitrogen alloy. At present, domestic 2205 duplex steel products include welded pipe, seamless pipe, steel plate, bar, forging, strip, etc. The early duplex stainless steel can resist medium strength uniform corrosion and chlorine stress corrosion fracture, but its performance will be greatly reduced when used in welding. In order to improve this situation, nitrogen is added to 2205 dual phase steel, which not only improves the corrosion resistance, but also has good welding performance. It has high strength, good impact toughness and good overall and local stress corrosion resistance.

The yield strength of 2205 dual phase steel is twice that of austenitic stainless steel, which enables designers to reduce the weight when designing products, making this alloy more cost-effective than 316317l. This alloy is particularly 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 for welded structures. Due to the special performance characteristics and wide application range of 2205 dual phase steel, it is the most widely used brand in dual phase steel.

*PrEN value:% Cr + 3.3x% Mo + 16x% n

Physical and mechanical properties of 2205 duplex stainless steel:

1. Density of 2205 dual phase steel: 8.0g/cm3.

2. 2205 duplex steel tensile strength: σ b≥620Mpa。

3. Yield strength of 2205 dual phase steel: σ 0.2≥450Mpa

4. 22205 duplex steel elongation: δ ≥25%。

Corrosion resistance of 2205 duplex stainless steel:

1. Uniform corrosion: due to the chromium content (22%), molybdenum (3%) and nitrogen content (0.18%) of 2205 dual phase steel, the corrosion resistance of 2205 is better than 316L and 317L in most environments.

2. Local corrosion resistance: the content of chromium, molybdenum and nitrogen in 2205 dual phase steel makes it have strong resistance to point corrosion and interstitial corrosion in oxidizing and acidic solutions.

3. Stress corrosion resistance: the dual phase microstructure of 2205 dual phase steel helps to improve the stress corrosion cracking resistance of stainless steel. In the presence of certain temperature, tension, oxygen and chloride, chloride stress corrosion will occur in austenitic stainless steel. Since these conditions are not easy to control, the use of 304L, 316L and 317L is limited in this regard.

4. Corrosion fatigue resistance: 2205 dual phase steel has high corrosion fatigue resistance due to its high strength and corrosion resistance. The processing equipment is easily affected by corrosive environment and loading cycle. The characteristics of 2205 are very suitable for such applications.

2205 duplex stainless steel structure: the chemical composition of 2205 duplex steel can obtain the ideal microstructure 50 after 1900 ° / 1922 ° f (1040 ° / 1080 ° C) solid melt annealing α /  fifty γ 。 If the temperature of heat treatment is higher than 2000 ° F, it may lead to the increase of ferrite composition. Like other duplex stainless steels, 2205 duplex steel is easily affected by intermetallic precipitation. The intermetallic phase precipitates between 1300 ° F and 1800 ° F, and its precipitation rate is the fastest at 1600 ° F. Therefore, we need to test 2205 to ensure that there is no intermetallic phase. Refer to astm-a923 for the test.

Processability of 2205 duplex stainless steel:

1. Hot forming: we suggest that forming should be carried out below 600 ° F as far as possible. During hot forming treatment, the whole workpiece shall be heated as a whole and shall be carried out in the temperature range of 1750 ° f to 2250 ° F. 2205 dual phase steel is very soft at this temperature. If the temperature is too high, 2205 dual phase steel is prone to hot tearing. Below this temperature, austenite will fracture. Below 1700 ° F, the intermetallic phase will form quickly due to the influence of temperature and deformation. After hot forming, it shall be subject to solid melt annealing at a minimum temperature of 1900 ° F and quenching to restore its phase balance, toughness and corrosion resistance. We do not recommend stress relief, but if this is necessary, the material should be solid melt annealed at a minimum temperature of 1900 ° F, then rapidly cooled and water quenched.

2. Cold forming: 2205 dual phase steel can be cut and cold formed. However, due to its high strength and hardness, 2205 dual phase steel needs cold forming more than austenitic steel. Because of its high strength, springback should be fully considered.

3. Heat treatment: 2205 duplex steel shall be annealed at a minimum temperature of 1900 ° F, then rapidly cooled and water quenched. This treatment is applied to solid melt annealing and stress relief. If the stress relief treatment is carried out at a temperature lower than 1900 ° F, it is easy to lead to the precipitation of harmful metallic or non-metallic phases.

4. Mechanical machinability: on high-speed machine tools, the feed rate and cutting speed of 2205 dual phase steel are the same as 316L. If the carbonization knife is used, the cutting speed is reduced by about 20% compared with 316L. The performance of machinery and equipment and its components plays a key role here.

5. Welding: 2205 alloy has good weldability. The properties of 2205 dual phase steel are that the welding metal and heat modified part still maintain the same corrosion resistance, strength and toughness as the base metal. The welding of 2205 dual phase steel is not difficult, but its welding procedure needs to be designed so that after welding, it can maintain a good phase balance and avoid the precipitation of harmful metal phase or non-metal phase.

Application fields of 2205 duplex stainless steel: neutral chloride environment, oil refining industry, petrochemical and chemical industry, transmission pipeline for chemical industry, oil and natural gas industry, pulp and paper industry, chemical fertilizer industry, urea industry, phosphate fertilizer industry, seawater environment, energy and environmental protection industry, light industry and food industry, food and pharmaceutical industry equipment, high-strength structural parts, Submarine pipeline, flue gas desulfurization, osmotic desalination and desalination equipment, sulfuric acid plant, offshore engineering fasteners, etc.