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What Is The Difference Between Inconel and Incoloy?
Inconel® is a family of nickel-chromium superalloys known for high strength, corrosion resistance, and oxidation resistance at elevated temperatures. Well-suited to demanding applications, Inconel alloys typically comprise 50–70% nickel, 15–25% chromium, and other elements such as iron, cobalt, molybdenum, and tungsten. The specific composition of an Inconel alloy depends on its intended application.
Although it’s sometimes informally referred to as “Inconel steel,” Inconel isn’t a steel. It’s a nickel-based superalloy developed for environments where conventional steels—and many stainless grades—lose strength, oxidize, or corrode too quickly to perform reliably.
These properties make Inconel a common material choice across industries including aerospace, nuclear, food, chemical processing, oil and gas, power generation, and medical devices. Inconel can be machined using turning, milling, drilling, and grinding, though its strength and work-hardening behavior require appropriate tooling and process control. It also shouldn’t be confused with Incoloy: Inconel has a higher nickel content, while Incoloy contains more iron.
Typical applications of Inconel include aircraft and rocket engines, oil and gas drilling and production equipment, and gas turbines used in power generation. It’s also used for medical implants and surgical instruments due to its biocompatibility and corrosion resistance, as well as in automotive components and food-processing and heat-treatment equipment.
Tips and Considerations when Purchasing Inconel
Inconel is valuable but relatively expensive. So, you want to get everything right when purchasing it. The tips and considerations below can help you choose a suitable alloy for your application and the right quantity:
Inconel Grades
The grade depends on the application’s requirements. Common options include Inconel 600, 617, and 625, which are often selected for corrosion resistance and elevated-temperature performance, as well as Inconel 718, X-750, and 601, which are chosen where higher strength or creep resistance is required.
When comparing Inconel grades, focus on what the alloy must withstand in service. Operating temperature and exposure conditions, together with the balance between corrosion resistance and mechanical strength, will usually narrow the shortlist before availability, form, and certification come into play.
Common Uses and Selection Criteria
| Inconel grade | Primary strength | Typical environments | Why it’s chosen |
|---|---|---|---|
| Inconel 600 | Oxidation and corrosion resistance | High-temperature chemical and heat-treatment equipment | Stable performance across a wide temperature range with good resistance to many corrosive media |
| Inconel 601 | High-temperature oxidation resistance | Furnaces, thermal processing, heat shields | Improved creep and oxidation resistance compared to 600 at elevated temperatures |
| Inconel 625 | Corrosion resistance with high strength | Marine, chemical processing, oil and gas | Excellent resistance to pitting and crevice corrosion, especially in chloride environments |
| Inconel 718 | High strength at elevated temperature | Aerospace, gas turbines, high-load components | Precipitation-hardened alloy selected for strength, fatigue resistance, and creep performance |
| Inconel X-750 | Strength and relaxation resistance | Springs, fasteners, turbine components | Maintains mechanical properties under long-term stress and heat exposure |
Quantity and Sizing
Some key factors you’ll need to consider are the specific type of alloy, the size and shape of the components, and the manufacturing process to be used. Once you’ve reviewed all these factors, you can start to calculate the amount of Inconel material you need to order. Order slightly more material than you think you need in case of unexpected problems.
Specify Exactly What You’re Buying Before You Request Quotes
Most quote delays and wrong-material issues come down to the same problem: the purchase order doesn’t describe the Inconel material clearly enough. Before requesting pricing, it helps to define the requirement in a way that leaves little room for interpretation at the mill, service center, or quality stage.
| Specification detail | What to define | Why it’s important |
|---|---|---|
| Alloy and designation | Grade, UNS number, governing standard (ASTM / AMS / ASME) | Prevents material substitution and ensures compliance with design requirements |
| Product form | Bar, plate, sheet, pipe, tube, forging, cut-to-size | Availability, lead time, and pricing vary significantly by form |
| Dimensions and tolerances | Thickness, diameter, length, machining allowance | Avoids excess machining cost or unusable stock |
| Condition / heat treatment | Annealed, solution treated, precipitation hardened | Mechanical properties can vary widely by condition |
| Documentation | MTR/CMTR, heat number traceability, test results | Critical for quality control, audits, and regulated industries |
If you’re working out sizes or allowances, TechSteel’s metal weight calculator can help estimate material requirements before quoting.
Quality Control and Testing
These procedures are critical. They ensure the material’s integrity, help identify defects in raw materials, prevent early in-service failures, and highlight problems that could occur during production. Critical quality control measures include chemical analysis, mechanical testing, and non-destructive testing. Destructive testing is ideal for evaluating the properties of the Inconel material in more detail than with NDT methods.
Environmental Considerations
Some eco-friendly options or considerations when sourcing Inconel alloys include recycled Inconel, Inconel alloys from sustainable sources, and Inconel alloys with low environmental impact. In addition to sourcing eco-friendly Inconel alloys, several other eco-friendly considerations can be taken when using Inconel, such as design for recyclability, reducing waste, and proper disposal.
Customization Options
A wide range of customization possibilities for Inconel exist. It can be cut to size using various methods to create custom-shaped parts, be alloyed with other elements to optimize specific properties, and coated with numerous materials to meet the specific needs of various applications. Emerging technologies, like additive manufacturing, allow you to create parts with complex geometries difficult to produce using traditional manufacturing methods.
Logistics and Shipping
Choose an experienced shipper who can meet your specific needs, pack your Inconel items tightly to prevent them from shifting around during shipping, and declare the value of your shipment accurately to ensure the shipment is properly insured. Tracking your shipment enables you to correct problems. With international shipments, choose a reliable supplier, be aware of customs regulations, and consider using a freight forwarder.
Certifications and Compliance
Purchasing Inconel materials certified to ASTM standards and NACE compliance ensures the materials’ quality, performance, and reliability. It’s especially critical for applications that expose the materials to harsh environments, or the material’s failure could have serious consequences. ASTM and NACE certifications can also help ensure that the materials have the desired properties and are suitable for the intended use. Some industries have regulations requiring you to use Inconel certified to ASTM or NACE standards.
Choosing an Inconel Supplier
An experienced Inconel supplier should be able to confirm material traceability, explain substitutions, and supply the correct documentation without delay. It’s also important to clarify whether material is coming from stock or mill supply, as this can significantly affect lead times. Clear communication around specifications, condition, and certification at quote stage helps avoid rework and rejected material later on.
Inconel: Versatile and High Performing
Inconel is a versatile, high-performance material ideal for demanding applications. It offers various benefits that can help manufacturers add value to their products and parts, including high strength and excellent heat and corrosion resistance. Inconel is often used in extreme environments where components are subjected to high heat, pressure, and mechanical loads.
While employing the tips and considerations discussed above can help, choosing the right Inconel for your application can still be challenging. Working closely with a reliable and knowledgeable supplier can help clear up that uncertainty and ensure the material is suited to the intended service conditions.
Although Inconel is relatively expensive, it justifies its cost through superior performance and reliability in demanding applications, particularly where material failure would carry high operational or safety risk.
