Understanding Nickel Alloys – Monel® and Hastelloy®

A Guide to Understanding Nickel

Nickel is one of the leading options for applications that necessitate high strength, corrosion-resistant materials. Its strength and versatility make this material an appealing choice in the engineering, energy, and plumbing industries. It has a melting point of 1453° C, is magnetic, and is highly ductile on its own. However, one of nickel’s biggest advantages is its ability to merge with other materials to create nickel alloys.

The unique properties of nickel mean that manufacturers can optimize nickel alloys to deliver more desirable features. Industrial applications, for example, will commonly utilize nickel alloys to create tougher, more corrosion-resistant equipment that performs well at both high and low temperatures. As nickel alloys often perform well at temperatures of up to 1000° C, they are particularly suited for harsh, demanding environments.

There are approximately 3,000 different nickel alloys currently in use across a diverse range of industries. Stainless steel is one popular option, making up approximately two-thirds of nickel alloy production. Other common nickel alloys include Monel® and Hastelloy®. To create alloys, nickel is most commonly combined with:

• Aluminum
• Chromium
• Copper
• Iron
• Titanium

The strength, ductility, and corrosion resistance of nickel alloys mean that they can be found in many types of products and equipment, including:

• Aircraft and power turbines
• Building materials
• Cell phones
• Aircraft
• Food preparation equipment
• Laboratory equipment
• Medical equipment
• Nuclear power systems
• Pharmaceuticals
• Transportation

What Is Monel®?

Monel® is a trademarked name that refers to copper-nickel alloys. There are a number of different types of Monel®, each with its own advantages. This alloy is much stronger than nickel alone, highly resistant to corrosion, and highly weldable.

Each of the five major types of Monel® is optimized for different applications, making this a versatile alloy that provides benefits to a number of different industries. Some properties and common usages of Monel® include:

• Monel® Alloy 400: With a wide temperature range and excellent corrosion resistance, Monel Alloy 400 is well suited for a diverse range of applications, from gasoline tanks to electronic components.
• Monel® Alloy K-500:Exhibits low permeability with high strength and corrosion resistance, making it a popular choice for equipment such as marine propeller shafts, scrapers, and oil well tools.
• Monel® Alloy K-500 Rev E:Produced to conform to the QQN 286 Form 1 spec, Revision E is best suited to provide corrosion resistance in sour gas environments.
• Monel® Alloy K-500 Rev F:Designed for components that must be solution annealed at 2050°F because of the presence of titanium carbide Revision F conforms to the QQN 286 Form 2 spec.
• Monel® Alloy K-500 Rev G:Produced to pass the slow strain rate tensile test and conform to QQN 286 Form 2, Revision G is best suited for applications where susceptibility to intergranular cracking is not an option.
• Monel® Alloy R-405:Commonly found in fasteners, screw-machine products, and valve parts.

What Is Hastelloy®?

Hastelloy® is a superalloy, meaning that it has higher strength than standard alloy materials. It is primarily composed of nickel and molybdenum and comes in several grades, the most popular being Hastelloy® C-276, Hastelloy® C22 and Hastelloy® X.

• Hastelloy® C-276: Low carbon and silicon contents help to reduce concerns about welding with C-276.
• Hastelloy® C22: Higher chromium content allows C22 to provide exceptional resistance to chloride-induced pitting.
• Hastelloy® X: Provides excellent fabricability while maintaining strength at high-temperatures, ideal resistances to stress-corrosion cracking in petrochemical applications.

While each grade has its own advantages, they all exhibit exemplary levels of corrosion resistance. Other notable properties of Hastelloy® include:

• Oxidant resistance
• High ductility
• Strength at high temperatures

Hastelloy® is simple to fabricate and has both forging and cold working capabilities. Its low carbon content contributes to this superalloy’s corrosion resistance in welded products, as this minimizes carbide precipitation during the welding process.

Its many strengths mean that Hastelloy® is an excellent option for harsh environments that are likely to create high levels of corrosion and oxidization. In particular, it can withstand corrosion from:

• Chlorine
• Acetic acid
• Ferric chlorides
• Seawater
• Acetic anhydride

This superalloy is also a popular choice for piping material in the chemical processing and petrochemical industries, and can commonly be found in pressure vessels, heat exchangers, and nuclear reactors.

Contact Continental Steel for Any Nickel, Monel®, or Hastelloy® Projects

Nickel and its many alloys provide a wide array of benefits to projects spanning multiple industries. At Continental Steel, we provide high-performance materials optimized to your unique specifications. To learn more about the solutions we offer or to work with us on your next project, contact us today.

Monel® is a registered trademark of Special Metals

Hastelloy® is a registered trademark of Haynes International