Stainless steel 904L is a grade of stainless steel that has a high amount of chromium and nickel. It is one of the most common types of grades used for manufacturing valves, fittings, pipe and tubing. Stainless steel 904L is also commonly known as Hastelloy C276, which refers to its use in nuclear power plants. This type of stainless steel contains 1% to 3% nickel and 18% to 28% chromium. The presence of the elements makes it highly resistant to the corrosion and oxidation that can occur due to salt, chemicals, acids and seawater. This type of steel has good mechanical properties and is used for products that are subjected to high temperatures in the production process.
SS 904L Equivalent Grade
The datasheet below summarizes Rolex 904L stainless steel equivalent grade such as European EN (German DIN EN, British BS EN, French NF EN…), Chinese GB, ISO, Japanese JIS standard.
AISI 904L equivalent material
Grade (Steel Number)
ISO Name (ISO Number)
AISI SAE; ASTM
904L (UNS N08904)
EN 10088-2; EN 10088-3
GB/T 20878; GB/T 4237; GB/T 3280
Datasheet and Specification of 904L
The following data sheet summarizes the chemical composition, properties, heat treatment and equivalent grade of 904L stainless steel (SS904L).
Chemical Composition of 904L
The following data sheet gives SS 904L stainless steel chemical composition.
Chemical Composition, %
Bars and Shapes
Plate, Sheet, and Strip
Carbon = 0.002 percent max Carbon is a major impurity in stainless steel and can cause brittleness and reduce strength. The carbon content in 904L is less than 0.002 percent maximum, which ensures that it has good corrosion resistance and mechanical properties. Chromium = 19 – 23 percent Chromium is one of the main ingredients in stainless steel. It is present in varying degrees, but it is always present in greater quantities than nickel. Chromium’s ability to form chromium oxides on its surface makes it resistant to corrosion and allows for the structural integrity of stainless steel as a whole. However, if too little chromium exists within a given sample of stainless steel, then that sample will be brittle because chromium has a high melting point (1,742 °C). When chrome alloys are mixed with other metals like nickel or molybdenum (which have lower melting points), they become much less likely to crack or break when exposed to extreme heat. Copper = 2 percent max Copper is a good addition to stainless steel because it helps prevent corrosion. However, the maximum amount of copper permitted in 904L stainless steel is 2%. Manganese = 2 percent max Manganese is a hardening element. It increases strength and hardness, as well as ductility. Manganese is used in steel alloys to increase their strength, toughness, and resistance to stress corrosion cracking (SCC). Manganese has been added to the 904L stainless steel alloy at varying levels from 1.2 percent up to 2 percent, depending on the desired properties of the final product. At lower concentrations of manganese in 904L, there will be an improvement in properties such as toughness and SCC resistance relative to pure martensitic stainless steels such as 18/8 or 440C that do not contain any added alloying element besides carbon. However, when higher levels of manganese are used within 904L then it becomes difficult for manufacturers of these products to achieve consistent quality standards because they can affect both tempers (hardness) and grain size distribution within each batch produced by different manufacturers. Silicon = 1 percent One of the most common elements in stainless steel is silicon, which is used to improve the strength and toughness of the steel. The amount of silicon added to a particular grade of stainless steel depends on its intended use—for example, 316L can contain up to 0.25 percent carbon without losing its corrosion resistance, but if it contains more than that amount it will lose some of its corrosion resistance and become susceptible to pitting. The same goes for 904L: as long as you keep your carbon content below 1 percent (and preferably much lower), then your material will have sufficient corrosion resistance while still offering improved mechanical properties over other grades like 304L or 410. Sulfur = 0.03 percent min Sulfur is a naturally occurring element that can be found in many compounds, including sulfur dioxide. Sulfur is also used in a lot of industries, including fertilizer, petroleum and pharmaceuticals. In addition to its use as an ingredient in products such as rubber or fertilizer, sulfur is also commonly found naturally on earth’s crust. This makes it a common element that can be used to make steel stronger because it helps create compounds with other metals during the process of smelting (heating). Nickel = 23 – 28 percent Nickel is a hardening element, which means that it can increase the resistance to corrosion. Nickel is also used in surgical instruments, as well as other applications requiring high strength and hardness. Nickel has an atomic number of 28 and an atomic mass of 58.71 g/mol. This means that it has 28 protons, but it also has 30 neutrons in addition to those protons! This makes nickel quite heavy for its size!
Mechanical Properties of 904L
The following table lists Rolex 904L stainless steel (SS904L) mechanical properties such as yield strength, tensile strength, elongation and hardness.
AISI ASTM 904L Steel Mechanical Properties
Tensile Strength, MPa (ksi), ≥
0.2% Yield Strength, MPa (ksi), ≥
Elongation in 50 mm (2 in.), %, ≥
Rockwell Hardness (HRBW), ≤
904L (UNS N08904)
Bars and Shapes
Annealed, Hot-finished or cold-finished
Plate, Sheet, and Strip
Heat Treatment of 904L
Annealing: The recommended annealing temperatures for 904L wrought steel is 1095 °C (2000 °F).
Corrosion resistance of 904L stainless steel
Since the carbon content of 904L is very low (max. 0.020%), there is no carbide precipitation under general heat treatment and welding. This eliminates the risk of intergranular corrosion that occurs after general heat treatment and welding. Due to the high chromium-nickel-molybdenum content and the addition of copper elements, 904L can be passivated even in reducing environments such as sulfuric acid and formic acid. The high nickel content gives it a low corrosion rate even in the active state. In the concentration range of 0-98% pure sulfuric acid, 904L can be used at temperatures up to 40 degrees Celsius. In pure phosphoric acid in the concentration range of 0-85%, its corrosion resistance is very good. In industrial phosphoric acid produced by the wet process, impurities have a strong influence on the corrosion resistance. In all kinds of phosphoric acid, 904L corrosion resistance is better than ordinary stainless steel. In strongly oxidizing nitric acid, 904L has lower corrosion resistance compared to highly alloyed steel grades without molybdenum. In hydrochloric acid, the use of 904L is limited to a lower concentration of 1-2%. In this concentration range. 904L has better corrosion resistance than conventional stainless steels. 904L steel has a high resistance to pitting corrosion. Its resistance to crevice corrosion is also good in chloride solutions. 904L’s high nickel content reduces the rate of corrosion at pits and crevices. Ordinary austenitic stainless steels may be sensitive to stress corrosion in a chloride-rich environment at temperatures above 60 degrees C. This sensitization can be reduced by increasing the nickel content of the stainless steel. Due to the high nickel content, 904L has a high resistance to stress corrosion rupture in chloride solutions, concentrated hydroxide solutions and hydrogen sulfide-rich environments.
Processing performance of 904L
Welding performance of 904L
As with general stainless steel, 904L can be welded using a variety of welding methods. The most commonly used welding method for manual arc welding or inert gas shielded welding, welding rod or wire metal based on the composition of the base metal material and higher purity, molybdenum content requirements than the base material. Preheating is generally not necessary before welding, but in cold outdoor work, to avoid condensation of water vapor, the joint or the adjacent area can be uniformly heated. Note that the local temperature should not exceed 100 ℃, so as not to lead to carbon agglomeration, causing intergranular corrosion. Welding should use a small linear energy, continuous and fast welding rate. After welding generally do not need heat treatment, if heat treatment, must be heated to 1100-1150 ℃ after rapid cooling.
Matching welding consumables: welding rod (E385-16/17), welding wire (ER385).
Machinability of 904L 904L machining characteristics similar to other austenitic stainless steel, the process has a tendency to sticky tool and work hardening. Must use positive front angle carbide tools, sulfide and chlorinated oil as cutting coolant, equipment and process should be to reduce the premise of machining hardening. Slow cutting speed and tool feed should be avoided in the cutting process.
Tube plate is the main component of heat exchanger, which is composed of shell and baffle. Tube sheets are used to transfer heat between two fluids by providing a tube support and also enhancing heat transfer. The tube sheets are made of stainless steel or carbon steel with various surface treatments such as painting, zinc plating, polyester powder coating etc., depending on the working conditions.
How to calculate the tube sheet in heat exchanger?
A tube sheet is the outermost structural component of a heat exchanger, and it’s what supports the tubes and other components. It can be made of steel or stainless steel. Tube sheets can come in either flat or corrugated varieties. The shape will depend on how you want your heat exchanger to look, but both types work well as long as they’re constructed with sufficient strength and rigidity.
How to weld the tube sheet?
Welding of tube sheet is done by using electric arc welding or gas metal arc welding. In electric arc welding, there are two processes that are used to weld the tube sheet; first one is SMAW (Shielded Metal Arc Welding) and second process is GMAW (Gas Metal Arc Welding). In gas metal arc welding, there are two processes used to weld the tube sheet; first process is GTAW (Gas Tungsten Arc Welding) and second process is FCAW (Flux Cored Arc Welding).