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Difference between Monel and Hastelloy

by | Jul 3, 2021 | Industrial supplier & distributor

Hastelloy is a versatile alloy that may be utilized in a variety of industrial applications. Chromium, tungsten, molybdenum, carbon, cobalt, vanadium, aluminium, titanium, copper, nickel, niobium, iron and other elements are included in the material composition. Hastelloy is available in a variety of grades, each with its own set of properties. On the other hand, Monel is a nickel-copper alloy with a high proportion of copper and nickel in the manganese, silicon, iron and carbon composition. Monel 400 Springs and Hastelloy are both Nickel-based alloys used in different applications; read on to know some significant differences between Monel and Hastelloy.

Hastelloy Properties

Hastelloy is a nickel-molybdenum alloy designed to withstand high temperatures and high concentrations of reducing acids. It is not impacted by grain-boundary carbide precipitation after welding because it is not affected by grain-boundary carbide precipitation. It can be utilized even if it is welded.

Monel Properties

When compared to steel and Monel, Monel work hardens rapidly and is harder to manufacture. It must be operated and rotated at moderate speeds and low feed rates. It is often utilized in situations where the environment is very acidic. Monel is considerably more costly than stainless steel. Monel 400 Springs is notable for its toughness, which can be maintained across a wide temperature range. Monel alloy 400 has good mechanical characteristics at subzero temperatures. Impact resistance and a slight loss of flexibility enhance its hardness and strength. It does not undergo a ductile-to-brittle transition even when chilled to the temperature of liquid hydrogen.

How to Identify Monel and Hastelloy 

When new metallic goods are polished and have the same surface colour, it may be difficult to tell them apart. Hastelloy and other nickel alloys have a silvery colour, while Monel may have a yellowish-green tint or shade at the edges. However, looking at the unified number systems (UNS) that would designate them individually is the best method to identify them separately.

Nickel content in Hastelloy and Monel

Although both Hastelloy and Monel alloys include nickel, the amount of nickel added in their composition differs. While Monel alloys include approximately 30% to 40% copper, the nickel concentration varies between 60% and 70%, depending on the Monel grade produced. Hastelloy comprises large amounts of ferrous or iron, chromium, molybdenum, cobalt, and tungsten, while the remainder of nickel is added to the alloys that will be produced. As a result, certain Hastelloy have a lower content than Monel.

Monel and Hastelloy Melting Point

Melting points of Monel and Hastelloy grades are comparable up to 1350 degrees Celsius. However, depending on the grade and material composition, there is a slight variation. Although their melting points are comparable, Hastelloy grades have a more excellent heat resistance capability than Monel grades.

Monel and Hastelloy Yield Strength

The yield strength of Hastelloy may reach 364 MPa. The yield strengths of Monel grades may reach 345 MPa. As a result, Hastelloy grades are usually more durable than Monel 400 Springs grades.

Adding refractory metals like molybdenum, tungsten, and columbium to many of these alloys (Inconel 625, IN-102, Udimet620, and RA 383) may strengthen them. The alloys that arise have excellent oxidation resistance and high thermal strength.