Monel Stainless Steel
Monel stainless steel is a family of nickel-copper alloys (typically 52–67% nickel and 28–34% copper) with small amounts of iron, manganese, carbon, and silicon. Though not a true stainless steel (which is iron-based with chromium), Monel is often classified under high-performance corrosion-resistant alloys due to its exceptional durability in harsh environments. It has following key characteristics & functions:
1. Corrosion Resistance – Superior to many stainless steels, especially in acidic, alkaline, and saltwater environments (e.g., seawater, sulfuric/hydrochloric acids).
2. High Strength – Retains mechanical properties at both high and cryogenic temperatures.
3. Non-Magnetic – Ideal for applications requiring magnetic transparency.
4. Excellent Fabricability – Can be welded, machined, and formed into complex shapes.
5. Monel alloys resist pitting, stress corrosion cracking, and erosion, making them suitable for extreme conditions.
The applications of Monel stainless steel span in following critical industries fields:
- Marine Engineering: Propeller shafts, pump components, and seawater valves. - Chemical Processing: Reactors, heat exchangers, and piping for corrosive chemicals. - Oil & Gas: Downhole tools, valves, and offshore platforms. - Aerospace: Turbine blades and fuel tanks. - Medical Devices: Surgical instruments and implants (e.g., Monel 400).Monel’s niche lies in environments demanding both strength and corrosion resistance beyond conventional stainless steels.
1.Monel Stainless Steel K-500
Monel Stainless Steel K-500 It is an external nickel copper alloy that combines the excellent corrosion resistance of alloy 400 with greater strength and hardness. Alloy K-500 provides a yield strength three times higher than alloy 400. These enhanced characteristics require the addition of aluminum and titanium elements on top of nickel as the main element, as well as age hardening. During the aging hardening process, trace amounts of Ni3 (titanium, aluminum) particles precipitated into the matrix. The low magnetic permeability, high strength, and corrosion resistance of K-500 steel are widely used in oil well detection equipment and electronic components. An important characteristic is that K-500 remains non-magnetic even at very low temperatures. Time hardening will result in the original volume shrinkage. During the time hardening process, a round rod with a diameter of 2.5 × 10-4 inches undergoes shrinkage. To achieve good performance, the typical aging hardening process is maintained at 982 ℃ for 30 minutes and then water quenched and annealed. After being maintained at 593-607 ℃ for 16 hours, it is slowly cooled in the furnace at 9.4 ℃ -3.8 ℃ per hour until it reaches 482 ℃. Afterwards, cooling from 482 ℃ to room temperature may require some furnace cooling, air cooling, or quenching in between, without considering the cooling rate.
Monel Stainless Steel K-500 | ||||||||
|---|---|---|---|---|---|---|---|---|
Chemical compositions | ||||||||
| C≤ | Si≤ | Mn≤ | P≤ | S≤ | Cr | Ni | Mo | Cu≤ |
| 0.25 | 1 | 1.5 | - | 0.01 | - | 63-67 | - | rest |
| Fe≤ | Zr | AI | Ti | Bi≤ | Co | V≤ | W≤ | Nb≤ |
| 2 | - | 2月4日 | 0.25-1 | - | - | - | - | - |
Mechanical Properties | ||||||||
| Heat treatment | Tensile strength | Yield strength | Elongation | Hardness | ||||
| σb/MPa | σp0.2/MPa | σ5 /% | HBS | |||||
| - | - | - | - | - | ||||
2.Monel Stainless Steel 400
Monel Stainless Steel is nickel based corrosion-resistant alloy steel that has been used in industry for a long time. It has good comprehensive performance and a wide range of applications. Due to its excellent corrosion resistance, it has become an indispensable alloy. Its chemical composition is mainly composed of Ni, 30% Cu, and a small amount of Fe (1% -2%). Commonly used in various heat exchange equipment, boiler feedwater heaters, pipelines, containers, pumps, valves, shafts, etc. in petroleum and chemical processing, seawater desalination equipment, salt production equipment, propeller shafts, gasoline and water tanks, etc.
Monel Stainless Steel 400 | ||||||||
|---|---|---|---|---|---|---|---|---|
| ISO | JIS | ASTM | UNS.SAE | DIN | EN | |||
| Ni68Cu28Fe | NW4400 | N0.4400 | MONEL400 | 2.436 | NiCu30Fe | |||
Chemical compositions | ||||||||
| C≤ | Si≤ | Mn≤ | P≤ | S≤ | Cr | Ni | Mo | Cu≤ |
| 0.3 | 0.5 | 1.5 | - | - | - | 63-67 | - | 28-34 |
| Fe≤ | Zr | AI | Ti | Bi≤ | Co | V≤ | W≤ | Nb≤ |
| 2 | - | - | - | - | - | - | - | - |
Mechanical Properties | ||||||||
| Heat treatment | Tensile strength | Yield strength | Elongation | Hardness | ||||
| σb/MPa | σp0.2/MPa | σ5 /% | HBS | |||||
| - | ≤480 | ≤195 | ≤35 | - | ||||