S31803 dual phase stainless steel is composed of 21% chromium, 2.5% molybdenum and nickel nitrogen form 4.5% duplex stainless steel alloy. It has high strength, good toughness and good overall and local stress corrosion resistance. The yield strength of S31803 duplex stainless steel is two times that of austenitic stainless steel, this feature enables designers to reduce weight in the design of products, let this alloy has a price advantage than 316317L. This alloy is particularly applicable to -50 degrees F/+600 degrees F temperature range. Beyond this temperature range of applications, also can consider this kind of alloy, but there are some limitations, especially when used in welding structure.

S31803双相不锈钢特点：

The characteristics of S31803 duplex stainless steel:

1.S31803双相不锈钢与316L和317L奥氏体不锈钢相比,S31803双相钢在抗斑蚀及裂隙腐蚀方面的性能更优越,它具有很高的抗腐蚀能力,与奥氏体相比,它的热膨胀系数更低,导热性高。

1.S31803 dual phase stainless steel and austenitic stainless steel 316L and 317L compared, S31803 properties of dual phase steel in the resistance to pitting and crevice corrosion is more superior, it has very high corrosion resistance of austenite, and compared, its lower thermal expansion coefficient, high thermal conductivity.

2.S31803双相不锈钢与奥氏体不锈钢相比,它的耐压强度是其两倍,与316L和317L相比,设计者可以减轻其重量。2205合金特别适用于—50°F/+600°F温度范围内,在严格限制的情况下(尤其对于焊接结构),也可以用于更低的温度。

2.S31803 dual phase stainless steel and austenitic stainless steel are compared, the compressive strength is two times, compared with 316L and 317L, the designer can reduce the weight. Alloy 2205 is particularly applicable to - 50 degrees F/+600 degrees F temperature range, in a strictly limited circumstances (especially for welding structure), can also be used to lower the temperature.

化学成分：C≤0.030 Mn≤2.00 Si≤1.00 p≤0.030 S≤0.020 Cr 22.0～23.0 Ni 4.5～6.5 Mo3.0～3.5 N0.14～0.20(奥氏体-铁素体型）

Chemical composition: C = 0.030, Mn = 2 Si = 1, P = 0.030 S = 0.020 Cr and 22 ~ 23 Ni and 4.5 ~ 6.5 Mo3.0 ~ 3.5 N0.14 ~ 0.20 (austenite and ferrite)

S31803双相不锈钢应用领域 ：

S31803 dual phase stainless steel applications:

· 压力器皿、高压储藏罐、高压管道、热交换器(化学加工工业)。

Pressure vessels, pressure tanks, high pressure pipe, heat exchanger (chemical processing industry).

· 石油天然气管道、热交换器管件。

Petroleum natural gas pipeline, the heat exchanger tubes.

· 污水处理系统。

And the sewage treatment system.

· 纸浆和造纸工业分类器、漂白设备、贮存处理系统。

And the pulp and paper industry classifier, bleaching equipment, storage and processing system.

· 高强度耐腐蚀环境下的回转轴、压榨辊、叶片、叶轮等。

High strength corrosion environment of the rotary shaft, impeller blades, press roller, etc..

· 轮船或卡车的货物箱

Cargo tank, ship or truck

· 食品加工设备

And food processing equipment

S31803双相不锈钢标准：

S31803 dual phase stainless steel standard:

ASTM/ASME...........A240 UNS S32205/S31803

ASTM/ASME..A240 UNS S32205/S31803...

EURONORM...........1.4462 X2CrNiMoN 22.5.3

EURONORM..1.4462 X2CrNiMoN 22.5.3...

AFNOR...................Z3 CrNi 22.05 AZ

AFNOR....Z3 CrNi 22.05 AZ

DIN.........................W. Nr 1.4462

DIN....W. Nr 1.4462

S31803双相不锈钢抗腐蚀能力：

S31803 dual phase stainless steel corrosion resistance:

均匀腐蚀

Uniform corrosion

由于铬含量（22%），钼（3%）及氮含量（0.18%）,2205的抗腐蚀特性在大多数环境下优于316L和317L。

Because the chromium content (22%), Mo (3%) and nitrogen content (0.18%), 2205 of the properties of corrosion resistance is better than that of 316L and 317L in most environments.

局部抗腐蚀

Local corrosion

S31803双相不锈钢中铬、钼及氮的含量使其在氧化性及酸性的溶液中, 对点腐蚀及隙腐蚀具有很强的抵抗能力。

The content of chromium, molybdenum and nitrogen S31803 duplex stainless steel in the oxidizing and acidic solution, has a strong ability to resist corrosion and crevice corrosion.

抗应力腐蚀

Stress corrosion resistance

不锈钢的双相微观结构有助于提高不锈钢的抗应力腐蚀龟裂能力。在一定的温度、应张力、氧气及氯化物存在的情况下,奥氏体不锈钢会发生氯化物应力腐蚀。由于这些条件不易控制，因此304L、316L和317L的使用在这方面受到限制。

Dual phase microstructure of stainless steel is helpful to improve the resistance of the stainless steel stress corrosion cracking ability. At a certain temperature, oxygen tension exists, and the absence of chloride, austenitic stainless steel will happen to chloride stress corrosion. Because of these conditions is not easy to control, so the use of 304L, 316L and 317L are limited in this respect.

抗腐蚀疲劳

Corrosion fatigue

S31803双相不锈钢的高强度及抗腐蚀能力使其具有很高的抗腐蚀疲劳强度。加工设备易受腐蚀环境和加载循环的影响，S31803双相不锈钢的特性非常适合这样的应用。

High strength and corrosion resistance of S31803 duplex stainless steel which has high resistance to corrosion fatigue strength. Processing equipment susceptible to corrosion environment and cyclic loading, the characteristics of S31803 duplex stainless steel is very suitable for such applications.

结构

Structure

S31803双相不锈钢的化学成分在经过1900°/1922°F (1040°/1080°C)固熔退火处理后,可获得理想的微观结构50 α / 50 γ 。如果热处理的温度高于2000°F ,可能会导致铁素体成分的增加。像其他的双相不锈钢一样,2205 合金易受金属间相析出的影响。金属间相在1300°F和1800°F之间析出,在1600°F温度下,其析出速度最快。因此,我们需对S31803双相不锈钢进行试验，确保无金属间相，,试验参考ASTM A 923。

Chemical composition of S31803 duplex stainless steel after 1900 degrees /1922 degrees F (1040 degrees /1080 degrees C) solution annealed microstructure can obtain ideal 50 alpha / 50 gamma. If the heat treatment temperatures above 2000 degrees F, may lead to an increase in the ferrite components. Like other dual phase stainless steel, alloy 2205 is easily affected by the intermetallic phase precipitation. Intermetallic phases at 1300 DEG F and 1800 DEG between F at 1600 DEG F precipitation, temperature, the precipitation of the fastest. Therefore, we need to conduct experiments on the S31803 duplex stainless steel, to ensure that no intermetallic phase, testing, reference ASTM A 923.

S31803双相不锈钢加工

S31803 dual phase stainless steel processing

热成形

Hot forming

我们建议成形应尽量在600°F 温度以下进行。在进行热成形处理时,整个工件应整体受热,应在1750°F 到2250°F 的温度范围内进行,2205 合金在此温度下非常柔软。如果温度过高,2205合金易于热撕裂。如果低于此温度,奥氏体就会发生断裂。低于1700°F时,由于温度和形变的影响,金属间相会很快形成。热成形进行完后,应立即对其在最低为1900°F 的温度下进行固熔退火,并进行淬火来还原其相位平衡、韧性及抗腐蚀能力。我们不建议进行应力消除,但如果必须这样做,材料应在最低为1900°F 的温度下进行固熔退火,然后迅速冷却,进行水淬火。

We suggest that should be carried out in the following 600 degrees F temperature forming. In hot forming processing, the workpiece should be heated, should be in 1750 degrees F to 2250 degrees F within the temperature range of 2205 alloy under this temperature, very soft. If the temperature is too high, easy to hot tearing 2205 alloy. Below this temperature, the austenite will be broken. Below 1700 degrees F, because of the influence of temperature and deformation, intermetallic will soon form. After hot forming, should be an immediate solution annealed to at least 1900 degrees F temperature, and quenching to restore its phase equilibrium, toughness and corrosion resistance. We do not recommend eliminating stress, but if you must do so, materials to be solution annealed at a minimum of 1900 degrees F temperatures, then rapidly cooling, water quenching.

冷成形

Cold forming

S31803双相不锈钢可以进行切割和冷成形。然而,由于2205 合金自身的高强度及硬度,它比奥氏体钢铁更需要进行冷成形,也正因为它的高强度,要充分考虑到回弹的因素。

S31803 dual phase stainless steel can be cut and cold forming. However, due to the high strength and hardness of 2205 alloy itself, it than austenitic steel is more need for cold forming, also because of its high strength, should give full consideration to the factors of springback.