Being an industrialist I am very much familiar with Inconel products of high-nickel. In the extreme heat conditions, they are well-renowned for their outstanding performance. Inconel 625, 330, and 600 are extraordinarily popular for usage in furnace applications like annealing steel or heat treatment. However, is there any difference between Inconel 625, 330, and 600? to help and answer this question, I have provided a guide.
It is a special part of Incoloy family with high heat resistant properties and is more commonly termed as RA330 or Incoloy. The content of nickel that may range between 34%, 37% and 17-20% chromium, the Incoloy offer incredible oxidation toward resistant at a higher temperature ranging up to 2100 degree F or 1148 degree C- as nitriding and carburizing.
In common heat treat application, they can work well in rapid changes. The Incoloy are resistant toward thermal shocks. The Incoloy 330 maintains higher degree tensile strength compared to steel alloys. In fact, the Inconel offers better performance for oxidation, strength, oxidizing sulfur resistance, and carburization resistance.
Inconel 600 is considered one of the most popular materials in the Inconel family. It is highly resistant toward oxidation at a very high temperature. It has a minimum content of nickel as 72%. Compared to the Inconel 330 it has nickel content twice. The nickel content help in increasing high carburization and oxidation resistance, it can be effectively used in reducing sulfur, oxidation sulfur, or molten metal’s (like magnesium, zinc, or copper). It doesn’t possess the excellent tensile strength, thermal shock resistance, above-average oxidation and top notch level of carburization resistance. However, it exhibits incredible chloride stress cracking corrosion resistance.
Inconel 625 falls in between the Inconel 330 and Inconel 600 in nickel content and has 58% nickel. What’s the most abundant after nickel? It is chromium content that is 20-23%. The addition of molybdenum and columbium impacts power to peak performance for various temperatures. It is well known that it possesses superb strength as well as toughness in range of temperature between -32 degrees F or 0 degrees C to 2000 degree F or 1093 degree C.
It is seen that this sort of alloy possesses fatigue resistance, high creep rupture, and crevice corrosion resistance. However, it is welded easily in comparison to other known Inconel alloys. Some of the applications of the Inconel 625 are chemical plant equipment, seawater equipment, and engine exhausts. They are highly resistant to oxalic acids in comparison to other metals. They have to experience 6.0 mils/ year with an oxalic acid solution. In comparison to other steel, they also experience 44.6 mils per year in a similar solution. However, the sulfuric acid is less impressive in 10% concentration.
Which is appropriate for the application?
The answer could vary as per the application type. If one wishes to have high-temperature tolerance, then Inconel 600 is the best compared to 330, it is unsuitable for the sulfuric compound. However, for good resisting toward oxidizing and sulfur acid, the alloy 330 can be used. The 625 is resistant toward in most of the acids.
For straight resistant temperature, the metal temperature range could be -2000 degree F.