Monel® vs. Stainless Steel: What Are the Key Differences?

Monel® and stainless steel are two distinctive alloys that are used extensively in many different industries. Monel is a nickel-copper alloy ideal for severe situations due to its high strength and remarkable resistance to corrosion. Conversely, stainless steel, which is mostly made of iron, chromium, and nickel, is praised for its ability to withstand corrosion and its wide range of uses. 

Notwithstanding their shared characteristics, the composition, functionality, and uses of the two materials are very different. It is essential to comprehend the main differences between stainless steel and Monel to choose the appropriate material for your application.

This article will discuss the difference between Monel vs stainless steel in terms of composition, uses, types, and benefits.

What Is Monel?

Monel is a nickel-copper alloy known for its corrosion resistance and high strength. It is primarily composed of copper and nickel. Monel is remarkably resilient even in severe conditions. It is a desirable material for industrial and marine settings due to its resilience against seawater and acidic environments.

To learn more, see our full guide on Monel Alloys.

What Is Another Name for Monel?

Depending on the type, such as Monel 400, Monel is also known as Phyweld 400 or Nicorros LC. Monel 400 is a nickel-copper alloy. Monel alloy 405, referred to as Monel R405, is its free-machining grade. Monel exhibits corrosion resistance, making it suitable for various applications.

What Is Monel Made Of?

Monel, a nickel-copper alloy developed in 1905, consists primarily of 66% nickel, and 31.5% copper. This particular combination is the source of this alloy's exceptional strength and corrosion resistance. Traces of iron, manganese, carbon, and silicon are also present in Monel. Modern Monel manufacturing uses precise computerized control in an air induction furnace, as opposed to its traditional method of direct ore smelting. 

What Does Monel Look Like?

Figure 2 shows a picture of a Monel bracelet of ethnic design:

This image showcases Monel, a metallic alloy, exhibiting a distinctive metallic luster and often displaying a slightly yellowish or silvery hue, depending on its specific composition.

What Are the Different Types of Monel?

A wide variety of nickel alloys are available, each designed for a particular use. For example, Monel 400, known for its exceptional strength and resistance to corrosion, does well in chemical and marine environments. Autogenous and resistance welding are two areas in which Monel 401 shines, despite its intended usage in specialized electronics. Monel 404 has good brazing qualities and a low Curie temperature, making it suitable for electronic applications. Automatic screw machine stock is one use for the free-machining grade Monel 405. Due to its fatigue strength, monel 450 is highly suitable for components connected to seawater. Monel K-500 is perfect for oil-well drill collars and marine pump shafts because it combines increased strength and resistance to corrosion. The nickel-copper alloy Monel 502 is machineable similarly to austenitic stainless steels and has good creep and oxidation resistance.

What Is Monel Used For?

The corrosion resistance and high strength of monel alloys make them ideal for a wide range of applications in the chemical and hydrocarbon processing industries for: heat exchangers, pumps, valves, fittings, shafts, and fasteners. Monel alloys are a popular option in a variety of industries in which dependability and longevity are essential due to their remarkable resilience and tolerance to hostile environments.

What Are the Advantages of Monel?

The advantages of Monel include:

1. Exhibits exceptional corrosion resistance, making it suitable for harsh and corrosive environments.
2. Known for their robust strength, Monel alloys maintain structural integrity even in challenging conditions.
3. Maintains its performance at elevated temperatures, expanding its utility in various industrial applications.
4. Resists deformation under long-term exposure to high temperatures and stress, ensuring durability.
5. Possesses low magnetic permeability, making it suitable for applications in which magnetic interference is a concern.
6. Demonstrates ease of weldability, facilitating efficient fabrication and construction processes.

What Are the Disadvantages of Monel?

The disadvantages of Monel include:

1. Can be less readily available compared to more common materials, potentially impacting accessibility.
2. Machining Monel alloys can pose challenges, requiring specialized tools and processes.
3. Monel has a fairly high density, which may be a consideration in applications for which weight is a critical factor.
4. In certain conditions, Monel may be susceptible to galvanic corrosion when in contact with dissimilar metals.
5. While Monel demonstrates temperature resistance, there are limitations to its heat resistance compared to some other alloys, affecting its performance in extremely high-temperature environments.

Is Monel Heavier Than Stainless Steel?

Yes, Monel is generally heavier than stainless steel. Monel alloys have a higher density compared to most stainless steel grades, contributing to their greater weight. This difference in weight can be a consideration in applications in which material weight is a critical factor in design and functionality.

What Is Stainless Steel?

Stainless steel is a corrosion-resistant alloy composed of iron, chromium, nickel, and other elements. Chromium supplementation creates an oxide layer of protection on the surface that inhibits rust and increases durability. This alloy is extensively utilized in many different fields, including: industrial machinery, kitchenware, and construction.

To learn more, see our full guide on Stainless Steel Composition.

What Is Another Name for Stainless Steel?

Stainless steel, sometimes referred to as inox, is alternatively known as corrosion-resistant steel (CRES) or rustless steel. These terms are interchangeably used to describe this alloy, emphasizing its key attributes of corrosion resistance and durability across various applications.

What Is Stainless Steel Made Of?

Stainless steel is composed of iron, with a crucial inclusion of at least 10.5% chromium, which forms a protective oxide layer. Its strength, resilience to corrosion, and adaptability are further enhanced by the presence of other alloying elements including nickel and manganese, which total less than 1.2% of the material.

What Does Stainless Steel Look Like?

Figure 3 shows an image of stainless steel kitchenware:

This image captures the characteristic gleam of stainless steel, showcasing its metallic luster and often silvery or slightly grayish appearance, making it a popular choice for various applications.

What Are the Different Types of Stainless Steel?

Different varieties of stainless steel are available, each designed for a particular use. Austenitic steel (e.g., grades 304 and 316) is the most popular type and has excellent corrosion resistance as well as non-magnetic properties. Low-carbon ferritic steels, like 409 and 430, are less hardenable, yet are nevertheless used in auto trim and architecture. Martensitic steels are robust and more often used in surgical tools and cutlery because they can be heat-treated to harden them. Combining the qualities of both, austenitic-ferritic (duplex) steels offer strength and resistance to corrosion, making them ideal for chemical processing. Applications requiring hardened steel at lower temperatures use precipitation-hardened stainless steel, which has remarkable strength.

What Is Stainless Steel Used For?

Stainless steel is widely used in the production of cookware, cutlery, and kitchen accessories. Less ductile grades are typically used for utensils such as knives, but more ductile grades are used when making saucepans, cookers, sinks, and grills. Stainless steel stands out as a fundamental material in both home and industrial contexts due to its wide range of applications.

What Are the Advantages of Stainless Steel?

The advantages of stainless steel include:

1. Exhibits excellent corrosion resistance, ensuring longevity in diverse environments.
2. Withstands wear and tear, contributing to its long-lasting performance.
3. The non-porous surface of stainless steel makes it easy to clean, promoting hygiene in applications like kitchenware and medical equipment.
4. Stainless steel's strength and structural integrity make it suitable for a wide range of applications, from construction to industrial equipment.
5. Beyond functionality, stainless steel's sleek and modern appearance enhances the aesthetic appeal of products in various industries.

What Are the Disadvantages of Stainless Steel?

The disadvantages of stainless steel include:

1. Can be relatively expensive compared to other materials, impacting overall project costs.
2. The density of stainless steel is quite high, which may be a consideration in applications in which weight is critical.
3. Certain stainless steel grades exhibit magnetic properties, which may be undesirable in certain applications.
4. While durable, stainless steel is susceptible to scratches and dents, affecting its appearance over time.
5. Cold working stainless steel can be challenging, requiring specialized tools and processes.
6. Variations in the appearance of stainless steel can occur, impacting the desired aesthetic consistency in some applications.

Is Stainless Steel Softer Than Monel?

Yes, Monel is generally stronger than stainless steel. Monel's composition, including nickel and copper, contributes to its higher strength compared to stainless steel, making it a preferred choice in certain applications.

How To Choose Between Monel and Stainless Steel?

To choose between Monel and stainless steel:

1. Corrosion Resistance: If the application involves exposure to highly corrosive environments, such as: saltwater, acidic or alkaline solutions, or chemicals, Monel may be the better choice due to its exceptional corrosion resistance. Stainless steel is also corrosion-resistant but may be less suitable for extremely aggressive environments.
2. Strength and Durability: If high tensile strength and durability are critical, stainless steel is a strong and durable material suitable for various structural and load-bearing applications. Monel is also durable and has generally higher strength compared to stainless steel except for a few exceptional grades.
3. Cost Considerations: Evaluate the budget constraints for your project. While both Monel and stainless steel offer durability, Monel is often more expensive. Consider the financial implications of material selection.
4. Machinability: Consider the ease of machining required for your project. Stainless steel may be more readily machined than Monel, which can impact fabrication processes and costs.
5. Magnetic Properties: Assess the magnetic properties needed for your application. If non-magnetic properties are crucial, Monel may be preferred over certain stainless steel grades.

What Are the Properties of Monel and Stainless Steel?

Table 1 highlights the properties of Monel and stainless steel:

How Ductile are Monel and Stainless Steel?

Monel exhibits remarkable ductility, outperforming stainless steel and many other metals. Ductility refers to a material's capacity to deform under tensile stress without fracturing. Monel's exceptionally ductile nature allows for effortless shaping into intricate forms, showcasing its versatility across diverse applications.

To learn more, see our full guide on the Meaning of Ductile.

What Is the Tensile Strength of Monel and Stainless Steel?

Tensile strength, which indicates a material's maximum ability to withstand stress under tension, demonstrates how much better Monel K500 is than stainless steel 316. Approximately 700 MPa is the remarkable tensile strength of Monel K500, which is more than the 550 MPa of stainless steel 316. This discrepancy highlights Monel's superior resistance to applied forces, making it a strong option for challenging structural situations.

Do Monel and Stainless Steel Rust?

Yes, Monel and stainless steel can both corrode, but Monel generally exhibits higher corrosion resistance due to its higher nickel content. Monel's increased nickel concentration enhances its ability to withstand corrosion, especially in challenging environments like exposure to saltwater. In contrast, stainless steel, while corrosion-resistant, may show signs of rust over time, particularly in harsh conditions.

Are Monel and Stainless Steel Brittle?

No, Monel and Stainless Steel are not inherently brittle. While ferrous materials like stainless steel tend to become brittle at low temperatures, Monel differs. It exhibits increased mechanical strength with minimal impairment of ductility at lower temperatures, making it less prone to brittleness.

How Can Xometry Assist You With Your Monel or Stainless Steel Needs?

Xometry provides precision manufacturing solutions to meet your needs for Monel or stainless steel. Specializing in on-demand manufacturing, Xometry provides an array of services encompassing design and production, such as CNC machining, injection molding, milling, 3D printing, sheet metal fabrication, cutting, turning, and urethane casting. Being a leader in the field, they guarantee superior solutions that satisfy particular material criteria, such as those for Monel and stainless steel, for a variety of industries.

How To Identify Monel and Stainless Steel?

You can use these steps to distinguish between stainless steel and Monel. Start by examining the material's magnetic properties. Monel is not magnetic, while stainless steel can be, so if the tested piece is magnetic this means that the material cannot be Monel. Next, note the hue: The color of Monel is usually yellowish or silvery, while the color of stainless steel is silver or gray. Examine Monel's resistance to corrosion; it works well in maritime settings. Do a spark test as well. Stainless steel makes more sparks than Monel, which either produces fewer sparks or is spark-resistant.

What Are the Applications of Monel and Stainless Steel?

Applications of Monel and stainless steel include the following:

Monel:

1. Marine Engineering
2. Chemical Processing
3. Aerospace Components
4. Oil & Gas Industry
5. Electrical and Electronic Parts

Stainless Steel:

1. Construction
2. Medical Equipment
3. Automotive Industry
4. Kitchen Appliances
5. Architecture

Monel is favored in marine and chemical environments due to its superior corrosion resistance, while stainless steel finds widespread use in construction and medical applications, showcasing its versatility in various industries.

Is Monel Magnetic?

No, Monel is typically non-magnetic because it lacks iron in its composition. Iron is the element that imparts magnetism to metals, and without it Monel cannot be magnetized. Monel's non-magnetic properties make it a good choice for applications involving MRI-compatible implants in the medical area or electrical connectors in electronics production. But some Monel alloys might have traces of iron in them, which would make them magnetic to a small extent.

Is Stainless Steel a High-Quality Metal?

Yes, stainless steel is considered a high-quality metal. Its exceptional biological cleanability, superior to aluminum and copper and comparable to glass, makes it a preferred choice in applications demanding hygiene, such as pharmaceutical and food processing plants. The combination of cleanability, strength, and corrosion resistance contributes to stainless steel's reputation as a high-quality material.

How Much Do Monel and Stainless Steel Cost?

Prices for Monel metal normally range from $2.50 to $3.00 per pound. As opposed to this, stainless steel is often less costly, costing between $0.34 and $0.66 per pound. The disparity in price can be attributed to the different expenses involved in the production, availability, and composition of stainless steel and Monel.

Summary

This article presented Monel and stainless steel, explained each of them, and discussed their key differences. To learn more about Monel and stainless steel, contact a Xometry representative.

Xometry provides a wide range of manufacturing capabilities and other value-added services for all of your prototyping and production needs. Visit our website to learn more or to request a free, no-obligation quote.

Copyright and Trademark Notice

1. Monel® is a trademark of Special Metals Corporation

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