Nickel-Iron Alloys
Nickel-Iron alloys are materials composed primarily of nickel and iron. Alloys of this type have density and strength which are higher than normal alloys, which in turn make them useful in applications that require high durability or specific levels of strength. These alloys are also known as nickel-iron-chrome alloys, and can be used in applications from petrochemicals and aerospace to automotive and general engineering.
The properties of nickel-iron alloys are determined by their chemical composition and heat treatment. The nickel and iron in the alloy form a solid solution, which gives the alloy its strength and ductility. Other elements can also be added to the alloy to increase its strength or improve its wear resistance. Specifically, chrome and cobalt are common elements added to these alloys due to their ability to increase durability and resistance to oxidation.
Single-phase nickel-iron alloys are categorized according to the standard GB/T 7737-1997. This standard contains four primary alloys - NiFe30, NiFe35, NiFe45, and NiFe50 - and seven supplementary alloys - NiFe20, NiFe25, NiFe60, NiFe70, NiFeC60, NiFeC30 and NiFeC35. Each of these alloys feature different chemical compositions and mechanical properties, which are determined by their individual alloying components and heat treatment methods.
NiFe30 is a chromium-containing, single-phase ferritic alloy composed primarily of nickel and iron. It has a decent balance of hardness and ductility, making it suitable for applications where a combination of strength and formability are needed. Due to its higher chrome content, NiFe30 has better oxidation resistance and corrosion resistance than other alloys in the GB/T 7737-1997 standard. It is commonly used in the manufacture of nuclear power-plant components and automotive parts.
NiFe35 is similar to NiFe30, but with a slightly higher alloy content. This gives it increased hardness and improved resistance to wear and corrosion. This alloy is primarily used in heavy industry applications, such as petrochemical and industrial engines.
NiFe45 is a high strength, single-phase alloy composed of nickel, iron, and chrome. It has superior strength and ductility, making it ideal for applications that require superior impact resistance and fatigue resistance. In addition, due to its high chrome content, it has superior oxidation resistive properties. This alloy is mainly used for industrial components, such as turbine blades, bearings, and shafts.
NiFe50 is a chromium-free, single-phase alloy composed of nickel and iron. It has a combination of high strength and formability, making it suitable for applications where a combination of both attributes is needed. Additionally, its relatively low alloy content makes it less susceptible to corrosion than other alloys in the standard. This alloy is often used in the manufacture of turbine components, pumps, and valves.
The supplementary alloys in the standard are similar in composition to the primary alloys, but may contain additional elements or higher concentrations of certain elements. These alloys have different chemical and mechanical properties than the primary alloys and are therefore used in several different applications.
Nickel-Iron alloys are a versatile and highly sought-after material for numerous engineering applications. They are strong and durable, and can hold their own against the elements. By understanding the chemical composition and heat treatment of these alloys, they can be put to use in everything from aircraft components to automotive parts.
