| Customization: | Available |
|---|---|
| Type: | Stainless Steel Coils |
| Standard: | ASTM, AISI, GB, JIS, DIN, EN |
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725LN is a high alloyed urea grade austenitic stainless steel with a very low carbon content. This steel was developed to solve the selective corrosion of hot ammonium carbamate in urea production. Intergranular corrosion and selective corrosion as urea grade stainless steel.
When it is as low as 4000~850'C (the solubility limit of carbon in austenite), carbides that prevent Cr from precipitating can effectively prevent intergranular corrosion. When m(C)≤0103%, the base material or weld is 400%~850°C intergranular corrosion will not occur in corrosive media. In media such as long-term selective or urea, selective corrosion is related to the corrosive medium and metallographic structure. δ_first corrodes the ferrite phase. Pure austenite has the best corrosion resistance to this type of medium.
Because 725LN has an extremely low ferrite content, it is almost entirely austenite. Therefore, this steel will not be selectively corroded either. It should pass the urea grade stainless steel ASTMA-262 "E" method Huey intergranular corrosion test and selective corrosion test.
725LN Stainless Steel Applications
Stainless Steel 725LN Chemical Composition
| C | 0.02 max | Si | 0.40 max |
| Mn | 2.0 max | P | 0.02 max |
| S | 0.01 max | Cr | 24-26 |
| Mo | 2.0-2.6 | Ni | 21-23.5 |
| N | 0.1-0.15 |
Stainless Steel 725LN Mechanical Properties
| Grade | Tensile Str(MPa) min | Yield Strength0.2% Proof (MPa) min |
Elongation(% in 50mm) min | Hardness | |
| Rockwell C (HR C) | Brinell (HB) | ||||
| 725LN | 540 - 570 MPa | 448 | > 40% | 31 max | 293 max |
▪ The yield point, Rp0,2: >250 MPa
▪ Impact resistance, KV: > 60J
▪ Modulus of elasticity, E: 190 GPa
▪ Thermal capacity, cp: 500 J * kg-1 * K-1
▪ Thermal conductivity, λ: 15 W * m-1 * K-1
▪ Linear expansion coefficient, α: 15.7 * 10-6 K-1
▪ Specific resistance, Ω: 0.8 mkOhm * m
Intergranular corrosion
The carbon content of 725LN is below 0.102%, and the possibility of intergranular corrosion is very small. In order to prevent the increase of carbon during welding, it should be cleaned before welding, especially to prevent the use of carbon arc gouging.
Preheating and post-weld heat treatment - Generally speaking, the preheating and post-weld heat treatment of austenitic stainless steel are good.
Select welding method
Due to the high content of alloy elements in 725LN, tungsten inert gas arc welding should be used as much as possible on the side in contact with the medium. Due to the high temperature of the argon arc, the heat is concentrated, the argon gas flow is cooled, the weld is cooled quickly, the heat affected area is small, and the alloy element combustion loss is small, which is conducive to the molten metal of the weld to eventually become a complete austenite structure. In addition, tungsten inert gas arc welding does not produce spatter, the plate surface is good, and it is conducive to corrosion protection. But for this equipment, the thickness of the plate is 8mm, and it is not economical to use only tungsten inert gas arc welding. A combination of tungsten inert gas arc welding, electrode arc welding filling and covering should be used to avoid the cleaning of the weld and improve the welding efficiency.
Urea stainless steel 725LN has a high degree of alloying and low impurity content, which fundamentally guarantees the welding quality. Under the control of appropriate process measures, the welding method using argon arc welding bottom electrode arc welding hood achieves satisfactory welding quality.
| 725ln stainless steel pipe sizes and specifications | |
| Grade | 725ln |
| Cold rolled stainless steel coil | Thickness: 0.3mm- 3.0mm, Width: 1000mm - 2000mm, Surface: 2B/BA/SB/8K/HL/1D/2D etc |
| Hot rolled stainless steel coil | Thickness: 3.0mm - 16mm, Width: 1000mm - 2000mm Surface: No.1/pickling |
| Standard | ASTM A240/A480, ASTM B688, ASTM B463/SB463, ASTM B168/SB168, ASTM B443/SB443/B424/SB424B625/SB625 B575/SB575, JIS G4303, BS 1449, DN17441, G4305 |
Q1: Do you accept the trial order ?
A1: Yes,if we have the exactly size in stock.we can delivery even 1 piece/meter .
Q2: Can I have free sample before making orders?
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