Inconel vs Titanium: Understanding the Use Cases of High Spec Metals

Inconel vs titanium, both high-specification metals suitable for a wide variety of high-stress and corrosion-resistant applications. Though both have desirable physical and mechanical properties that make them ideal for extreme conditions, Inconel and titanium are very different metals. Here, we’ll examine the main properties, manufacturing concerns, and use cases differentiating Inconel vs titanium.

Inconel

Inconel is a trade name for a family of nickel-chromium superalloys made by Special Metals Corporation. It has an incredibly high tolerance for extreme temperatures and can withstand about 2,000°F (depending on the alloy) without losing strength. Aside from high temperatures, it also performs well in cryogenic temperatures.

In addition to its high-temperature performance, Inconel has excellent mechanical properties at room temperature. Inconel 725, for example, has a tensile strength of up to 180 ksi—twice the strength of structural steel. Some Inconel alloys, such as Inconel 718, undergo precipitation hardening to increase their tensile strength further. Inconel is also highly corrosion-resistant, including oxidation, pitting, crevice corrosion, and corrosion cracking.

Inconel’s heat resistance and other properties make it a valuable metal for the most demanding conditions. Its high melting point also contributes to its ability to perform in extreme environments. Inconel’s high tensile strength ensures that it can withstand significant mechanical stress without deformation. However, like most superalloys, it is significantly more expensive than common metals like stainless steel, aluminum, and pure titanium.

Machining Inconel

The strength that makes Inconel such a valuable material for extreme conditions also makes it tough to machine. It’s exceptionally hard and is prone to work hardening during machining, which can damage cutting tools and deform the workpiece.

Stress-relieving Inconel through solutionizing before machining can help reduce surface hardness and limit work hardening, reducing the stress and wear on tooling. Ceramic tooling is recommended, as it is capable of fast, continuous cuts that minimize work hardening. It is also important to avoid pecking, which can increase work hardening.

Welding Inconel

Welding Inconel is difficult because the welds tend to crack. However, certain Inconel alloys are designed to be weldable. These are usually TIG (tungsten inert gas) welded with Inconel 625, the most weldable Inconel alloy, as a filler metal. While TIG welding doesn’t typically require a filler, it’s recommended for welding Inconel because it is hard to fuse two pieces without cracking them.

Inconel Applications

Because of its high temperature, chemical, and corrosion resistance, Inconel is ideal for aerospace, oil and gas, and marine applications. Some common use cases of Inconel include:

• Jet engine exhausts.
• Turbines.
• Exhaust couplings.
• Flare stacks.
• Natural gas piping.
• Marine propeller blades.
• Aerospace and marine fasteners.
• Heavy machinery parts.

Inconel is an ideal material whenever extreme temperature and corrosion resistance are needed, especially when high temperatures degrade the strength and oxidation resistance of other metals. Its corrosion-resistant nature makes it particularly valuable in harsh environments where other metals might fail.

Additionally, Inconel’s corrosion-resistant properties ensure long-term durability and reliability in critical applications. This corrosion-resistant metal is essential for maintaining the integrity and safety of components exposed to harsh chemicals and high-stress conditions. Overall, Inconel’s corrosion-resistant characteristics make it a preferred choice for industries requiring high-performance materials.

Furthermore, Inconel’s high melting point ensures that it remains stable and retains its properties even under extreme thermal stress. Its melting point is significantly higher than that of many other metals, making it suitable for applications involving high temperatures.

Titanium

Titanium is an elemental metal with an exceptionally high strength-to-weight ratio, making it very useful for applications where minimizing weight is critical, like aerospace structural components. It is about as strong as stainless steel but only half the weight. This exceptional strength-to-weight ratio allows for lighter yet equally strong components. However, these properties come with a higher price tag than more common metals like aluminum and stainless steel, though it’s generally much cheaper than Inconel.

Titanium does not react with oxygen and water at ambient temperatures. Like Inconel, titanium forms a passive oxidation layer on its surface that protects the material. This makes titanium highly corrosion-resistant, even against strong sulfuric and hydrochloric acids. Furthermore, titanium is also biocompatible and non-toxic, so it’s used for many medical applications in the medical industry.

Titanium is available in both commercially pure and alloyed grades. The most common alloy, Ti 6Al-4V, is alloyed with aluminum and vanadium and accounts for about half of all titanium used globally. This and other titanium alloys are designed to be harder, stronger, and/or easier to work than pure titanium. Commercially pure titanium (CP) is softer and more ductile than titanium alloy, but its corrosion resistance is outstanding.

Titanium’s impressive strength-to-weight ratio also makes it an ideal choice for automotive applications where performance and efficiency are crucial. In the construction of high-performance vehicles, titanium’s strength-to-weight ratio helps reduce overall vehicle weight, thus improving speed and fuel efficiency. Additionally, the strength-to-weight ratio benefits sporting equipment, providing athletes with robust yet lightweight gear that enhances performance without adding unnecessary bulk.

Machining Titanium

The properties that make titanium such a useful metal make it very difficult to machine. Like Inconel, titanium is susceptible to work hardening. CP titanium is also very gummy when machining and forms long, continuous chips that can interfere with the cutting tool. This characteristic also makes it susceptible to galling. This can be reduced by using a lot of high-pressure coolant to remove chips as soon as possible and keep the tool flutes clear.

When machining titanium, avoid interrupted cuts and keep the tool in motion at all times when contacting the workpiece. Excessive contact will cause the tool to rub, creating excess heat that leads to work hardening. Machining at a lower speed and higher feed rate can significantly reduce heat generation.

While Inconel is extremely hard and rigid, titanium is much more flexible, so workpieces require a secure grip and a machine setup that is as rigid as possible. Titanium and its alloys are very elastic, which causes springback and chatter during machining and can result in a poor surface finish.

Welding Titanium

Welding titanium and its alloys is relatively straightforward. The techniques and equipment for welding titanium are similar to those for other high-specification metals, such as stainless steel or nickel-base alloys. Titanium requires more careful attention to cleanliness and inert gas shielding than other metals. Air contamination can ruin titanium welds.

Titanium Applications

The mechanical properties of titanium, particularly its strength-to-weight ratio, are very useful in the aerospace and automotive industries. Ti 6AL-4V accounts for almost half of all alloys used in aerospace applications. It’s also commonly used in the medical industry due to its superior corrosion resistance and biocompatibility.

As mentioned, titanium is half the weight of stainless steel but just as strong, making it ideal for applications where reducing weight is crucial. For example, using titanium, which is half the weight of other materials, can significantly improve fuel efficiency in the aerospace industry. Additionally, titanium’s use in sports equipment, due to it being half the weight of traditional metals, provides athletes with high performance and reduced fatigue. In the medical industry, titanium’s property of being half the weight of other strong materials makes it perfect for implants and prosthetics, providing strength without unnecessary bulk.

Some common uses of titanium include:

• Aircraft engines and frames.
• Armor plating.
• Naval ships.
• Spacecraft.
• Missiles.
• Landing gear.
• Exhaust ducts.
• Artificial joints.
• Hardware for setting or repairing bones.
• Implanted medical devices.
• Sporting equipment.
• Bicycle frames.

Inconel vs Titanium

Industrial Metal Service specializes in supplying stainless steel, aluminum, titanium, and Inconel to machine shops, fabricators, and manufacturers in the San Francisco Bay Area. We also ship nationwide with no minimum order quantity. Our San Jose warehouse is stocked with an extensive inventory of Inconel and titanium alloys, including new metals sourced from U.S. mills and verified metal remnants offering considerable savings.

If you’re looking for a supply of Inconel or titanium, we can help. Call us to discuss your metal supply requirements, and we’ll ensure you get what you need.