Incoloy 800, Incoloy 800H and Incoloy 800HT are three alloys in the Incoloy family. You will notice that their names are very similar.

In fact, these three alloys are very similar indeed. They differ only slightly in their carbon, aluminium and titanium content.

In this article, we will explain the relationship and differences between these three alloys.

Before the advent of Incoloy 800, the Inconel 600 alloy was already used in a wide range of applications. In some high temperature, high corrosion applications, Inconel 600 was extremely successful with its high nickel content and high chromium content.

However, there is a growing awareness of the value of nickel metal. And nickel metal is relatively scarce in many countries. Over time, nickel has gradually become a strategic material. The price of nickel has risen as a result.

In response to this rise in nickel prices, a search was made for materials with a lower nickel content to partially replace Inconel 600 in high-temperature applications. It is in this context that Incoloy 800 has been developed.

Incoloy 800 has a lower nickel content and a higher iron content than Inconel 600. This significantly reduces the cost of the material. At the same time, thanks to the efforts of the developers, Incoloy 800 has been developed in such a way as to ensure maximum resistance to high temperatures and corrosion while reducing costs.

Initially, when Incoloy 800 was introduced, it was divided into two grades. The normal Incoloy 800 was called Grade I. In order to improve the creep strength and fracture strength of the product in certain applications, a high carbon Incoloy 800 material was developed. At the time, this material was known as Incoloy 800 Grade II.

Grade II has undergone many iterations as Incoloy 800 has been improved over and over again. From the chemical composition, to the heat treatment regime, to the grain size requirements, it all began to differ from Grade I. Grade II has since been separated from Incoloy 800 to form a new grade, Incoloy 800H, which has even better creep fracture resistance than Incoloy 800. It plays an irreplaceable role in some specific applications.

After Incoloy 800H was officially identified, manufacturers generally recognised the material. The number of manufacturers who can produce Incoloy 800H is increasing. Among them, Special Metals, the developer of Incoloy 800, still produces Incoloy 800H of a higher quality than other producers. They are the industry leader in the pursuit of higher creep resistance in their alloys. They produced Incoloy 800H with stricter control of the carbon, aluminium and titanium content. They subsequently named the material Incoloy 800HT.

Overall, Incoloy 800H controls the carbon content on the basis of Incoloy 800 and Incoloy 800HT further controls the carbon, aluminium and titanium content on the basis of Incoloy 800. The diagram below shows how they relate.

Incoloy 800, Incoloy 800H and Incoloy 800HT are similar in many respects.

The differences between them are mainly in the carbon, aluminium and titanium element content. This results in a difference in creep strength.

We can produce Incoloy 800, Incoloy 800H and Incoloy 800HT to exacting standards and you can contact us for your requirements.