Hastelloy Alloy

1.B-type alloys
B-type alloys are known for their high percentages of nickel and molybdenum. Like nickel, molybdenum offers high resistance to corrosion. It is notable for its ductility and has one of the highest melting points of all the naturally occurring elements. These alloys are formulated to withstand extreme reducing conditions, such as environments with hydrochloric, hydrobromic, and sulfuric acids.

B-2 alloy
This grade of alloy typically contains 65 percent nickel, 30 percent of molybdenum, and small percentages of iron, carbon, cobalt, chromium, manganese, silicon, phosphorus, and sulfur. It offers superior corrosion resistance to hydrochloric acids at any concentration or temperature. However, it is not resistant to oxidizing agents.

B-3 alloy
The B-3 alloy has an average composition of 65 percent nickel, 30 percent molybdenum, with trace amounts of manganese, cobalt, and chromium. It provides excellent resistance to pitting and corrosion, along with superior thermal stability compared to the B-2 alloy. Like the B-2 alloy, it is likely to prematurely deteriorate if exposed to oxidizing agents.

2.C-type alloys
Alloys that fall within the C-family have high percentages of nickel, molybdenum, and chromium. The addition of chromium increases the formability of these types of alloys, allowing them to withstand elevated temperatures and reducing atmospheres. Most C-type alloys can be formed using different cold and hot working methods, such as deep drawing, press forming, and punching.

C-4 alloy
The C-4 alloy consists of about 60 percent nickel, 18 percent chromium, 16 percent molybdenum, 3 percent iron, and 2 percent cobalt. The remainder comprises silicon, sulfur, carbon, titanium, and other elements. Along with corrosion resistance, it has a high ductility, which makes it suitable for deep drawing.

C-22 alloy
The C-22 alloy is one of the most used alloys for flue gas desulfurization systems and pharmaceutical reaction vessels. Usually, it contains about 58 percent nickel, 20 percent chromium, 13 percent molybdenum, 3.5 percent iron, 3 percent tungsten, and 2.5 percent cobalt, along with other trace elements. It is widely used for its weldability; however, it should not be used in environments exceeding 1,250ºF.

C-276 alloy
This type of alloy is the standard for petrochemical processing applications. Most of its composition is nickel. However, it contains an average of 16 percent molybdenum, 15 percent chromium, 5.5 percent iron, 4 percent tungsten, and minute percentages of other elements. It provides excellent resistance to pitting, intergranular corrosion, and oxidizing agents. However, it does not perform well in environments with hot concentrated nitric acid.

3.G-type alloys
G-type alloys typically contain tungsten, which has the highest melting point of all metals. This family of alloys can be welded using certain techniques, such as gas tungsten arc welding, submerged arc welding, and shielded metal arc welding.

G-3 alloy
This alloy has high percentages of tungsten and molybdenum, which makes it resistant to corrosion. On average, it consists of 22 percent chromium, 20 percent iron, 7 percent molybdenum, and a maximum of 5 percent cobalt. It contains trace amounts of other elements, with nickel being the dominant trace ingredient.

G-30 alloy
The G-30 grade is about 40 percent nickel, 30 percent chromium, 15 percent iron, and 5 percent cobalt, with traces of other elements. It is especially resistance to wet process phosphoric acid.

4.X-type alloys
Hastelloy X alloy (UNS N06002): It has superior oxidation resistance, high-temperature strength, and SCC resistance. Chemically Hastelloy X contains 44% Nickel, 23% Chromium, 20% iron, 10% molybdenum, 1% of Manganese and Silicon, and traces of other elements. They can be cold-worked and welded. This type of Hastelloy material is used for industrial furnace and gas turbine applications.

5.Hastelloy N (UNS N10003)
Hastelloy N contains 71% nickel, 16% molybdenum, 7% chromium, 5% iron, 1% silicon, and traces of other elements. Due to its higher temperature oxidation resistance properties, Hastelloy N is used in industrial applications like chemical process equipment.

Choosing the correct Hastelloy alloy requires an understanding of the specific application and the properties required of the alloy. Here are some factors to consider when selecting Hastelloy alloy.

Corrosion resistance: The primary advantage of Hastelloy alloy is its excellent corrosion resistance. The alloy should be chosen based on the specific corrosive environment it will be exposed to, such as acids, alkalis, or saltwater. Different Hastelloy alloys have different levels of resistance to various types of corrosion, so it's essential to select the appropriate alloy for the specific application.

Mechanical properties: Hastelloy alloys have varying mechanical properties, such as strength, ductility, and hardness. The alloy should be chosen based on the specific mechanical requirements of the application, such as the need for high strength or ductility.

High-temperature resistance: Hastelloy alloys are known for their high-temperature resistance, but different alloys have different temperature limits. The alloy should be chosen based on the maximum operating temperature of the application.

Fabrication and machinability: Hastelloy alloys can be challenging to machine and fabricate due to their high strength and toughness. The alloy should be chosen based on the specific fabrication and machining requirements of the application.

Cost: Hastelloy alloys can be expensive due to their high-performance properties. The alloy should be chosen based on the budget available for the application, while still ensuring that the necessary properties are met.