About 2304 Stainless Steel
Alloy 2304 duplex stainless steel is composed of 23% chromium and 40% nickel. The corrosion resistance of alloy 2304 is similar to that of 316L. In addition, its mechanical properties such as compressive strength are twice the 304/316 austenitic grade. This feature allows the designer to reduce the weight of the product during design, especially in the design of pressure vessels.
This alloy is particularly suitable for the temperature range of -50℃/+ 300℃(―58℃／572℃). Under severe restrictions (especially for welded structures), it can also be used at lower temperatures.
Compared with 304 and 316 austenite, due to the duplex microstructure of the alloy 2304 itself, the lower nickel content and higher chromium content make it more resistant to stress corrosion.
Application areas
1) Most areas used in 304 and 316
2) Pulp and paper industry (chips, chip storage tanks, black or white liquid tanks, classifiers)
3) Caustic alkali solutions, organic acids (anti-SCC)
4) Food industry
5) Pressure vessel (weight reduction)
6) Mining industry (abrasion/corrosion) standard
ASTM／ASME．．A240一UNS S32304
EURONOBaM．．1．4362一X2 Cr N1 23．4
AFNOR…Z3 CN 23．04 Az
DIN …W． Nr 1．4362
Anti-corrosion performance
General corrosion
Because of the high chromium content (23%) of alloy 2304 itself, the corrosion resistance of alloy 2304 stainless steel is almost the same as that of 316L.
Local corrosion resistance
23% chromium and 0.1% nitrogen content make 2304 duplex stainless steel more excellent in resistance to pitting corrosion and crevice corrosion than 316L.
Stress corrosion resistance The anti-stress
corrosion test carried out in the chloride ((8ppm 02) PH=7,>1000h, in the aqueous solution, proves that due to the higher chromium content and lower nickel content of 2304, 2304 stainless steel is better than 304L and 316L has a higher resistance to strong corrosion.
Other corrosion resistance
Alloy 2304 duplex stainless steel has passed most of the standard Ic test procedures, such as ASTM, A262E, and C tests.
Its corrosion rate in 65% boiling nitric acid is higher than that of 316L To be high. Due to its own high yield strength, this alloy is very suitable for abrasion and corrosion environments.
Chemical composition analysis
| C | Cr | Ni | Mo | N | Others |
|---|---|---|---|---|---|
| 0.02 | 23 | 4 | 0.2 | 0.1 | S=0.001 |
PREN(Cr%)+3.3(Mo%) = 16 (N%)> 24
Structure
the chemical composition analysis of 2304 idealized state after solution annealing treatment at a temperature of 9507℃／10507℃ (17427℃ / 19227℃), to obtain the microstructure of 50/50.
Alloy 2304 stainless steel microstructure is more stable than that of molybdenum-containing duplex stainless steel. The metal phase will appear after 10 hours of holding pressure in the temperature range of 7507℃/8507℃ (13827℃/15627℃). After heat treatment in the temperature range of 3507℃/5000℃ (6627℃/9327℃), the copper element in the 2304 stainless steel increases the hardness of the steel.
Hot forming
hot forming must be carried out in the temperature range of 1150/9007C (2100/16507F). After forming, It is recommended to perform solution annealing treatment in the temperature range of 9507/10507 C (21007/16507F) to restore its corrosion resistance and mechanical properties. During heating, care must be taken to avoid the creep of the product.
Cold forming
Cold forming of alloy 2304 stainless steel is not difficult. 304L and 316L cold forming equipment are also suitable for 2304. Due to its higher mechanical properties, including yield strength, higher pressure is required during cold forming. Finally, it is recommended to a solid solution. Annealing treatment to restore its mechanical properties and anti-corrosion properties is the same as hot forming. The solution and paste used for
Rust removal
are the same as 304L/316L. Due to its anti-corrosion properties, the pickling time is a bit longer than the austenite grade.
Machinability
in terms of drilling, the duplex structure 2304 machinability more. 316LEZ * and its performance considerably. Further, corrosion resistance of 2304 and greater cleanliness, as no sulfur. localized corrosion resistance is also Stronger. Has better machinery Processability.
Welding
*alloy 2304 stainless steel can be welded with the following equipment:
*TIG, manual and automatic
*PLASMA, MIG, SMAW, SAW, FCAW
*The compound microstructure makes it insensitive to thermal cracking.
*Welding parameters are controlled at 20-70% of ferrite under ideal conditions. We generally recommend heating 10-25KJ/cm at an intermediate temperature of up to 150℃ (302). In order to achieve the best results, we must consider the thickness of the product and the welding equipment (consultation is necessary). We do not recommend pre-welding or post-welding heat treatment, you can consider a complete solution annealing heat treatment.