Stainless Steel 904L/ UB6 (1.4539)
Stainless Steel - 904l/UB6 (1.4539)
Stainless Steel 904L, also known by its material number 1.4539 and UB6, is a high-performance austenitic stainless steel renowned for its superior resistance to corrosion, especially in harsh and aggressive environments. With a unique blend of high chromium, nickel, molybdenum, and copper content, 904L is designed to survive the harshest circumstances, making it a popular choice in a variety of industries, including chemical processing, oil & gas, and marine engineering.
Standards and Specifications:
- UNS: N08904
- DIN: 1.4539
- ASTM: A240, A312, A276
- EN: 10088-3
- NACE: MR0175/ISO 15156
Availability: Stainless Steel 904L is available in various forms, including sheets, plates, bars, pipes, and fittings. This versatility ensures that the material can be easily integrated into a wide range of applications.
Key Features:
- Exceptional Corrosion Resistance: 904L offers outstanding resistance to a wide range of corrosive environments, including sulfuric acid, phosphoric acid, and other strong reducing acids. This makes it highly suitable for chemical processing industries.
- High Alloy Composition: The material’s high levels of nickel, molybdenum, and copper enhance its resistance to pitting and crevice corrosion, as well as stress corrosion cracking.
- Non-Magnetic Properties: 904L remains non-magnetic even after extensive cold working, making it ideal for applications where magnetic properties are undesirable.
- High Strength and Durability: The alloy maintains excellent mechanical strength and toughness, ensuring long-term durability and reliability in harsh environments.
- Weldability: 904L can be easily welded using conventional welding techniques, which adds to its versatility in various construction and manufacturing processes.
Worldwide equivalent equivalent grade table 904l
| Standard | Grade | Material Number |
|---|---|---|
| EN (Europe) | X1NiCrMoCu25-20-5 | 1.4539 |
| UNS (USA) | N08904 | – |
| AFNOR (France) | Z2NCDU25-20 | – |
| DIN (Germany) | X1NiCrMoCu25-20-5 | 1.4539 |
| JIS (Japan) | SUS 890L | – |
| GOST (Russia) | 02ChN28M2D | – |
| BS (UK) | 904S13 | – |
Stainless Steel 904L Products
Stainless Steel 904l Pipe
Stainless Steel 904l Sheet & Plates
Stainless Steel 904l Flanges
Stainless Steel 904l Bars and Rods
Stainless Steel 904l Perforated Sheet
Stainless Steel 904l Pipe Fittings
Application
Stainless Steel 904L is used in a variety of demanding applications due to its superior corrosion resistance and mechanical properties:
- Chemical Processing: Ideal for handling sulfuric acid, phosphoric acid, and other aggressive chemicals.
- Oil & Gas Industry: Used in offshore environments, piping systems, and heat exchangers.
- Marine Engineering: Perfect for seawater cooling devices, marine exhaust systems, and other components exposed to seawater.
- Pharmaceutical Industry: Used in the manufacturing and storage of chemicals and in high-purity applications.
- Power Generation: Applicable in nuclear and fossil fuel power plants due to its resistance to high-temperature and corrosive environments.
Stainless Steel 904l Chemical Compositions
| Element | % Present (in product form) |
|---|---|
| Carbon (C) | 0.02 |
| Silicon (Si) | 0.70 |
| Manganese (Mn) | 2.00 |
| Phosphorous (P) | 0.03 |
| Sulfur (S) | 0.01 |
| Chromium (Cr) | 19.00 – 21.00 |
| Nickel (Ni) | 24.00 – 26.00 |
| Nitrogen (N) | 0.15 |
| Molybdenum (Mo) | 4.00 – 5.00 |
| Copper (Cu) | 1.20 – 2.00 |
| Iron (Fe) | Balance |
Stainless Steel 904l Mechanical Properties
| Mechanical Properties | Values |
|---|---|
| Tensile Strength (at RT) | 490-670 Mpa |
| Yield Strength (0.2% offset) | 220-310 Mpa |
| Elongation (at RT) | 35-40% |
| Hardness (Brinell) | 150 max |
| Impact Strength | Good |
Stainless Steel 904l Physical Properties
| Physical Properties | Values |
|---|---|
| Density | 7.85 g/cm³ |
| Melting Range | 1300 to 1390°C (2372 to 2534°F) |
| Thermal Conductivity | 11.5 W/(m·K) |
| Specific Heat Capacity | 20°C: 500 J/(kg·K) |
| Eectrical Resistivity | 20°C: 0.95 μΩ·m |
Processing / Welding
Stainless Steel 904L is known for its good formability and weldability, but there are some considerations and best practices to ensure successful processing and welding:
- Forming and Machining
- Welding
- Heat Input
- Post-Weld Cleaning
- Equipment and Tools
- Avoiding Contamination
- Consultation with Experts
- Testing
Corrosion Resistance
Stainless steel 904L is a non-stabilized austenitic stainless steel with low carbon content. It’s renowned for its excellent corrosion resistance, especially in harsh environments. Here’s why it’s favored in corrosive settings:
High Alloy Content: Stainless steel 904L has a high content of chromium, nickel, molybdenum, and copper, which contributes to its superior resistance to corrosion. Chromium forms a protective oxide layer on the surface, preventing corrosion.
Molybdenum Addition: Molybdenum enhances the alloy’s resistance to reducing acids, particularly sulfuric acid, phosphoric acid, and acetic acid. This makes it suitable for applications in industries like chemical processing, pharmaceuticals, and petrochemicals.
Copper Alloying: The presence of copper provides improved resistance to sulfuric acid and other reducing agents, enhancing the material’s overall corrosion resistance.
Pitting and Crevice Corrosion Resistance: Stainless steel 904L exhibits resistance to both pitting and crevice corrosion, which are common forms of localized corrosion in chloride-rich environments like seawater.
Resistance to Stress Corrosion Cracking: Its high nickel and molybdenum content makes it resistant to stress corrosion cracking, which is a significant concern in chloride-containing environments.
Durability in High-Temperature Applications: Stainless steel 904L maintains its corrosion resistance at elevated temperatures, making it suitable for applications where exposure to high temperatures is common.
Versatility: Its corrosion resistance makes it versatile for various applications including chemical processing equipment, pharmaceuticals, food processing, oil and gas, pulp and paper industries, and more.
However, despite its exceptional corrosion resistance, proper fabrication, handling, and maintenance are crucial to ensure optimal performance and longevity of stainless steel 904L in corrosive environments.
High Temperature Resistance 904l
Stainless Steel 904L exhibits excellent resistance to high temperatures, which is one of the key factors contributing to its suitability for various industrial applications. Here’s how it maintains its properties at elevated temperatures:
Oxidation Resistance: Stainless Steel 904L forms a protective chromium oxide layer on its surface when exposed to high temperatures. This oxide layer acts as a barrier, preventing further oxidation of the underlying metal, even at elevated temperatures.
Retention of Mechanical Properties: Unlike some other stainless steels that may experience significant degradation in mechanical properties at high temperatures, Stainless Steel 904L retains its strength, toughness, and ductility over a wide temperature range.
Creep Resistance: Creep is the tendency of a material to deform slowly under mechanical stress at high temperatures. Stainless Steel 904L has good creep resistance, allowing it to maintain its shape and integrity under prolonged exposure to elevated temperatures.
Stability of Austenitic Structure: Stainless Steel 904L is an austenitic stainless steel, which means it maintains its face-centered cubic (FCC) crystal structure even at high temperatures. This stability contributes to its ability to withstand thermal cycling without undergoing phase transformations or embrittlement.
Resistance to Thermal Fatigue: Thermal fatigue occurs when materials experience cyclic heating and cooling. Stainless Steel 904L has a low coefficient of thermal expansion and good thermal conductivity, which help reduce the risk of thermal fatigue failure at high temperatures.
Applications: Due to its high-temperature resistance, Stainless Steel 904L is used in various applications where exposure to elevated temperatures is common. These include heat exchangers, boilers, furnace components, exhaust systems, chemical processing equipment, and more.
Overall, Stainless Steel 904L’s ability to maintain its mechanical properties, resist oxidation, and withstand thermal cycling makes it a reliable choice for applications requiring high temperature resistance and long-term durability.
