904L Tube Sheet THK: 240 MM OD: 1385 MM

• Type: 904L Tube Sheet
• Material: 1.4539 (Alloy 904L/UNS N08904)
• Standard: ASME, etc
• Size: OD: 1385 MM
• THK: 240 MM

What is 904L?

904L super austenitic stainless steel contains 14.0-18.0% chromium, 24.0-26.0% nickel, and 4.5% molybdenum. 904L super austenitic stainless steel is a low carbon, high nickel, molybdenum austenitic stainless acid resistant steel. It has good activation-passivation transformation ability, excellent corrosion resistance, good corrosion resistance in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid, phosphoric acid, good pitting resistance in neutral chloride ion-containing media, and good resistance to crevice corrosion and stress corrosion resistance. It is suitable for various concentrations of sulfuric acid below 70℃, and has good corrosion resistance in acetic acid of any concentration and any temperature at atmospheric pressure, and in mixed acids of formic acid and acetic acid.
Super austenitic stainless steel 904L (00Cr20Ni25Mo4.5Cu; UNS: N08904; EN: 1.4539) is a highly alloyed austenitic stainless steel with low carbon content and good corrosion resistance in dilute sulfuric acid, designed for environments with harsh corrosive conditions. With a high chromium content and sufficient nickel content, the addition of copper makes it a strong acid resistance, especially for chloride interstitial corrosion and stress corrosion cracking with high resistance, not easy to appear corrosion spots and cracks, pitting resistance is slightly better than other steel grades, with good workability and weldability, can be used for pressure vessels.

• Tensile strength, Rm = 530 – 570 MPa
• Yield point, Rp0,2: >230 MPa
• Elongation, A: >35%
• Modulus of elasticity,E: 195 GPa
• Heat capacity, cp20℃= 450 J * kg-1 * K-1
• Heat conductivity, λ: 12 W * m-1 * K-1
• Linear Expansion Factor, α20℃=15,8 * 10-6 K-1
• Specific resistance: 1 Ω * mm2/m
• Hardness: <230 HB

Grades and standards.
UNS N08904 (American Society of Motor Vehicle Engineers and the American Society for Testing and Materials in 1967 jointly designed the standard), DIN1.4539 (German standard), ASTM A240 (American Society for Testing and Materials standard; the new standard will be classified as stainless steel series, the original standard ASME SB-625 will be classified as nickel-based alloy series), SUS890L.
The metallographic structure of 904L stainless steel:
904L is completely austenitic organization, compared with the general austenitic stainless steel with high molybdenum content, 904L is not sensitive to the precipitation of ferrite and alpha phase.
Physical and mechanical properties.
Density: 8.0g/cm3.

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
US		European Union		ISO		Japan		China
Standard	Type	Standard	Grade (Steel Number)	Standard	ISO Name (ISO Number)	Standard	Grade	Standard	Grade
AISI SAE; ASTM	904L (UNS N08904)	EN 10088-2; EN 10088-3	X1NiCrMoCu25-20-5 (1.4539)	ISO 15510	X1NiCrMoCu25-20-5 (4539-089-04-I)	JIS G4303	SUS 890L	GB/T 20878; GB/T 4237; GB/T 3280	015Cr21Ni26Mo5Cu2

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.

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
ASTM	AISI Type	Tensile Strength, MPa (ksi), ≥	0.2% Yield Strength, MPa (ksi), ≥	Elongation in 50 mm (2 in.), %, ≥	Rockwell Hardness (HRBW), ≤	Product forms	Conditions
ASTM A276/A276M	904L (UNS N08904)	490 (71)	220 (31)	35	–	Bars and Shapes	Annealed, Hot-finished or cold-finished
ASTM A240/A240M		490 (71)	220 (31)	35	90	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.

What is a tube sheet?

Tube sheets are steel plates for pipes used for heat exchangers, boilers, pressure vessels, and condensers. Tube sheets are made of various materials depending on the temperature and pressure requirements of the application. Tube sheets consist of a number of tubes in a normal size range or large diameter tubes. Tube sheets are not fully drilled but have bolting holes around the perimeter and in the center area. Tube sheets contain bolt holes that connect to the tube ends. The tube sheet is stabilized with dowel pins and sometimes with additional structural supports. The gasket is placed between the tube sheet and channel cover.
Tube sheets are plates for pipes used for heat exchangers, boilers, pressure vessels, and condensers.
They can be made of carbon steel or stainless steel. Most tube sheets have a built in membrane that isolates the tube from the pressure inside the vessel it is protecting.
Tube sheets are made of carbon steel, stainless steel or other materials depending on the temperature and pressure requirements of the application.

Tube plates are used in a wide range of applications including heat exchangers, boilers, pressure vessels and condensers. Their use is usually limited by their operating temperature which may vary from less than 450°C up to 1200°C. For example:

• Steel tube sheet fabrication (ASTM 1474)
• Stainless steel tube sheet fabrication (ASTM 1573)

Tube sheets consist of a number of tubes in a normal size range or large diameter tubes.

The tubesheet is the main structural component in a heat exchanger and plays an important role during operation, such as preventing thermal fatigue of the tubes from overheating and avoiding localized buckling.
Tube sheets are generally made from carbon steel plates or stainless steel plates with welded seams to form a tube plate assembly that withstands high temperatures with minimal wall thicknesses. The assembly can be welded together by mechanical means (welding), or by using electric arc fusion welding methods (e.g., submerged-arc welding).
Tube sheets are not fully drilled, but have bolting holes around the perimeter and in the center area.

Tube sheets do not have bolt holes in the center area of the tube sheet. The reason for this is so that when you’re installing a wall system, there’s no need to cut any material around your window or door openings because they won’t be there yet.
Tube sheets contain bolt holes that connect to the tube ends.
Tube sheets are used in the construction of steel tubular members such as columns, beams and trusses. Tube sheet sizes are based on the outside diameter of the tube material being used. Tube sheets have bolt holes that connect to tubes ends; these bolt holes can be located at different positions on a tube sheet depending on its size.

The tubeplate is stabilized with dowel pins and sometimes with additional structural supports.
The gasket is placed between the tube sheet and channel cover.

It prevents leakage and is made of rubber, but can also be made of other materials.

China Tube Sheets Manufacturer www.epowermetals.com offers 904L Tube Sheet THK: 240 MM OD: 1385 MM.