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Stainless steel 904L alloy is a super austenitic stainless steel. High levels of chromium and nickel, plus molybdenum and copper, ensure the product's excellent corrosion resistance. With a high alloy chemistry of 25% nickel and 4.5% molybdenum, stainless steel 904L outperforms molybdenum-containing stainless steels 316L and 317L in resistance to chloride stress corrosion cracking, pitting and corrosion. 904L steel was originally developed to resist corrosion in dilute sulfuric acid and has very good corrosion resistance. Stainless steel 904L is easy to weld and process in standard workshop manufacturing practices.
Rolex 904l, also known as rolex 904l steel, is the material used by Rolex to make watch cases. In fact, Rolex also used 316L stainless steel before. It was not until 1985 that stainless steel 904L was first used, and a solid watch strap was used. It was not until 2003 that all watches were replaced with 904L steel. So, why did you choose 904L?
In fact, both 316L and 904L are super austenitic stainless steels. Both are non-magnetic and have no effect on the accuracy of the watch. 904L steel contains more chromium, so it is more corrosion-resistant than 316L. In addition, Rolex 904L steel is easier to grind and polish than other brands, and even serious bumps can be restored by grinding.
In the professional field, 904L is the second best stainless steel material after 2507 super duplex stainless steel. Compared with 316L, its advantage is not only corrosion resistance. 904L steel is much more stable than 316L in extreme chemical environments, and its bending strength and tensile strength are also better than 316L.
Grade | Alloy 904L |
Density | 7.95 g/cm3 |
Melting Point | 1300 – 1390°C |
Electrical Resistivity | 33.5 Microhm-in at 68°C |
Thermal Conductivity | 12.9 W/m-°K |
Modulus of Elasticity | 190 GPa |
Specific Heat | 450 J/kg-°K (0 – 100°C) |
Grade | N≤ | Cr | Mo | Cu | P≤ | C≤ | Mn≤ | S≤ | Si≤ | Ni |
904L | 0.1 | 19.0-23.0 | 4.0-5.0 | 1.0-2.0 | 0.045 | 0.02 | 2.0 | 0.035 | 1.0 | 23.0-28.0 |
Grade | Tensile, min, ksi[MPa] | Yield, min, ksi[MPa] | Elongation, %(min) |
N08904 | 71【490】 | 31【220】 | 35 |
STANDARD | WERKSTOFFNR. | UNS | JIS | BS | AFNOR | EN |
904L | 1.4539 | N08904 | SUS 904L | 904S13 | Z1CNDU20.18.06Az | X1NiCrMoCu25-20-5 |
Product | Standard | Show |
Pipe SMLS & Welded | ASTM A312 |  |
Tube SMLS & Welded | ASTM A269/A249 |  |
Sheet /Plate | ASTM A240 |  |
Bars | ASTM A479 /ASTM A276 |  |
Forging | ASTM A182 |  |
Fittings | ASTM A403 |  |
Welding performance：
Like general stainless steel, 904 L can be welded by a variety of welding methods. The most commonly used welding methods are manual arc welding or inert gas shielded welding. The electrode or wire metal is based on the composition of the base metal and has a higher purity. The content of molybdenum is higher than that of the base metal. Preheating is generally not required before welding, but in cold outdoor operations, in order to avoid condensation of water vapor, the joints or adjacent areas can be heated evenly.
Note that the local temperature should not exceed 100 ℃, so as not to cause carbon agglomeration and cause intergranular corrosion. When welding, it is advisable to use small line energy, continuous and fast welding speed. Generally, no heat treatment is required after welding. If heat treatment is required, it must be heated to 1100-1150°C and then cooled rapidly.
Machinability：
The machining characteristics of 904L are similar to those of other austenitic stainless steels, and there is a tendency for tool sticking and work hardening during machining. Positive rake angle cemented carbide tools must be used, and vulcanized and chlorinated oil is used as cutting coolant. The equipment and process should be based on the premise of reducing work hardening. During the cutting process, slow cutting speed and feed amount should be avoided.
Corrosion resistance:
904L stainless steel has excellent corrosion resistance and performs well in strong acid, strong alkali and high temperature environments. Especially in chloride ion environments, its corrosion resistance is far superior to traditional 18-8 stainless steel.
Mechanical properties:
904L steel has high yield strength and tensile strength, and can withstand large forces and pressures. In addition, it also has excellent impact toughness, ductility and wear resistance, and is suitable for a variety of complex working conditions.
Magnetism:
904L has extremely low magnetic permeability and is almost unable to sense or maintain magnetism, which is very beneficial for some special application scenarios.
High temperature performance:
904L stainless steel has good high temperature stability and can maintain its excellent corrosion resistance and mechanical properties. Therefore, it is widely used in high temperature environments, especially in chemical, petroleum, pharmaceutical and other industries.
As a general-purpose corrosion-resistant material, 904L stainless steel sheet can be cold-rolled to obtain high-performance products, which can be used in many fields including food industry equipment, kitchen utensils and electronic industries. The use of each field is different, and the performance requirements of cold-rolled stainless steel 904L stainless steel are also different.
Especially when the thickness of the stainless steel strip is small, it is extremely important to seek its comprehensive cold working performance. By analyzing the influence of rolling and annealing processes on its properties and microstructure, and studying the influence of production process parameters on its microstructure and properties, experimental data can be provided for on-site production optimization and performance improvement.
Petroleum, petrochemical equipment, such as reactors in petrochemical equipment, etc.
Storage and transportation equipment for sulfuric acid, such as heat exchangers, etc.
The flue gas desulfurization device of power plant is mainly used in the following parts: the tower body, flue, baffle plate, internal parts, spray system, etc. of the absorption tower.
Scrubbers and fans in organic acid treatment systems.
Seawater treatment devices, seawater heat exchangers, paper industry equipment, sulfuric acid, nitric acid equipment, acid production, pharmaceutical industry and other chemical equipment, pressure vessels, food equipment.
Pharmaceutical plants: centrifuges, reactors, etc.
Plant food: equipment
904L is the matching steel grade for the strong corrosive medium of dilute sulfuric acid.
