4 Classifications of Superalloys

High-temperature alloys can be classified according to trademarks, basic elements, strengthening methods, and forming processes.

1.According to the trademark is divided into：

Hastelloy is a nickel-based corrosion-resistant alloy, mainly divided into nickel, chromium, molybdenum. Hastelloy is suitable for various chemical industries containing oxidizing and reducing media. The higher content of molybdenum and chromium makes the alloy resistant to chloride ion corrosion and improves the strength of the alloy, and the tungsten element further improves the corrosion resistance. Hastelloy has good corrosion resistance and thermal stability, and is mostly used in complex working environments such as aerospace and chemical fields.

Hastelloy grades usually start with a letter, such as Hastelloy C276, hastelloy B2, hastelloy B3, hastelloy X, hastelloy C2000.

Monel is a nickel-copper alloy, the main components are nickel and copper. Due to the high stability of copper, the alloy has very good corrosion resistance at room and low temperatures, and is particularly resistant to seawater as well as hydrochloric and sulfuric acids. An important feature of this alloy is that it generally does not produce stress corrosion cracking and has good machinability.

Monel alloy grades usually start with 4 and 5, eg Monel 400, Monel K500, Monel R405.

Inconel alloys are mainly nickel and chromium, and are oxidation and corrosion resistant materials ideal for use in extreme environments subject to high mechanical loads. At high temperatures, Inconel forms a thick and stable passive oxide layer that protects the surface from further erosion.

Inconel alloy grades usually start with the numbers 6 and 7, such as Inconel 625, Inconel 617, Inconel 718.

Incoloy is a super alloy composed of nickel-iron-chromium base, which can resist carbonization and oxidation in high temperature environment. Compared with inconel, the content of iron is increased, the cost is reduced, and the comprehensive performance of high temperature resistance and corrosion resistance is also slightly decreased. .

Incoloy alloy grades usually start with the numbers 8 and 9, such as Incoloy 800, Incoloy 825, Incoloy 800H/HT, Incoloy 925

2. According to the manufacturing process is divided into：

Deformed superalloys (70%), cast superalloys (20%) and new superalloys (10%) (powder metallurgy, etc.).

3. According to the main elements of the alloy, it is divided into：

Iron-based superalloy (heat-resistant alloy steel) (14.3%), nickel-based superalloy (80%) and cobalt-based superalloy (5.7%).

4. According to the reinforcement method can be divided into:

Solid solution strengthening, aging strengthening, oxide dispersion strengthening and grain boundary strengthening, etc.

Solid solution strengthened superalloys refer to a class of alloys that can only be strengthened by solid solution in addition to cold working.

Solution strengthening needs to be achieved by solution treatment. Dissolving more elements in the alloy matrix can increase the strength of the alloy.

Almost all Hastelloys are solid solution strengthened alloys. In MONEL, INCONEL and INCOLOY alloys, the grades starting with even numbers are basically solid solution strengthened alloys, such as Inconel 625 and Incoloy 800HT.

Age hardening, also known as precipitation hardening or precipitation hardening, refers to the precipitation of alloy elements that are solid solution at high temperature in a certain form (intermetallic compounds, etc.) The formation of dispersed and distributed hard particles causes resistance to dislocation cutting, which increases the strength and reduces the toughness. Its essence is the diffusion strengthening effect produced by the second phase.

The strength of age-hardening alloys is generally higher than that of solution-strengthening alloys.

Among the Hastelloy alloys, only Hastelloy C-22HS is an age hardening alloy. In Monel, Inconel, and Incoloy alloys, the grades starting with odd numbers are basically age-hardening alloys, such as Inconel 718, Inconel 725, and Incoloy 925.

Dispersion-strengthened alloys are alloys that are strengthened by adding dispersed particles.

Oxides added from the outside create barriers between the crystals, increasing the strength of the alloy. A common dispersed particle is Y 2 O 3 .

At high temperatures (above 1000°C), dispersion-strengthened alloys have higher strength than precipitation-strengthened alloys.

Grain boundary strengthening is to improve the state of grain boundaries by adding trace elements to achieve the purpose of strengthening superalloys.

Superalloy supplier

Wudenalloy has focused on the production and manufacture of superalloys for more than ten years. We are a principal worldwide supplier of corrosion-resistant alloy and other superalloy metals. We have a professional technical team and after-sales service, so we can offer high-quality Hastelloy, Incoloy, Inconel, Monel, Duplex Stainless Steel, and other alloy material. These materials are available in wire, bar, sheet&plate, pipe&tube, flange, forging, and other forms to meet the needs of our customers.

Request a quote now to get the competitive special alloy prices, you can also send emails to sales@wudenalloy.com, Wudenalloy is your trusted supplier of special alloy material.