Monel alloy, also known as nickel alloy, is an alloy made of metallic nickel as a base and added with other elements such as copper, iron, and manganese. The main material grades involved are: Monel 400, Monel 404, Monel K500, Monel R405, etc.

Hastelloy is the general name for the commercial grades of nickel-based corrosion-resistant alloys produced by Hastelloy International Corporation of the United States. The main material grades involved are: Hastelloy C276, Hastelloy C22, Hastelloy C59, Hastelloy C4, Hastelloy C2000, Hastelloy B2, Hastelloy B3, Hastelloy B4, Hastelloy G35, Hastelloy X, etc.

While these two alloys share similarities in corrosion resistance and high-temperature performance, their primary differences lie in their chemical composition and use. Monel and Hastelloy have significant differences in chemical composition and use.

In terms of chemical composition, the main difference between Monel and Hastelloy is the elements they contain. Monel alloy contains more iron and manganese elements, while Hastelloy contains higher chromium and tungsten elements. These differences give the two alloys different corrosion resistance and high-temperature properties.