Inconel 625 or 718 Tubing- Which Is Best for Your Application?

What are Inconel 625 and 718 Tubing?

Many characteristics of the Inconel alloy family, as well as more general characteristics of the nickel alloy and stainless steel families, are shared by Inconel 718 tubing and Inconel 625 tubing. They do, however, also have noticeable differences that allow for particular use cases.

What is Inconel 625?

Nickel and chromium make up the majority of Inconel 625’s elements. The high tensile strength and corrosion resistance, particularly resistance to crevice corrosion, are also provided by molybdenum and niobium. Its exceptional strength in situations with a cryogenic temperature or a very high temperature is due to columbium and molybdenum. Inconel 625 Tube offers good oxidation resistance and resistance to carburization, according to its technical bulletin, and it can keep its strength in conditions up to 2,000° F. With a few minor exceptions, Inconel 718 tubing and Inconel 625 tubing own chemical compositions that are largely identical.

What is Inconel 718?

It is exceptional for being precipitation hardened without succumbing to post-weld cracking. At 1,300° F, it can withstand creep rupture as well. Because of this feature, Inconel 718 can have alloy properties like good formability while still maintaining high tensile strength.

Inconel 718 Tubing are similar to common stainless steel grades in several ways due to its high weldability. On the other hand, Inconel 625 tubing in the annealed condition can be considerably stronger and, as already indicated, is especially well adapted to resisting corrosion, including that brought on by sea water conditions.

Difference in the Formability of Inconel 625 Tubing and Inconel 718 Tubing:

Both varieties of Inconel alloy have extremely high degrees of formability because of the high percentage of nickel in them. It is possible to cold shape and stamp Inconel 625 and 718. Both materials have remarkable tensile strength, but Inconel 718 tubing are especially well adapted to formability while keeping high strength in an annealed condition because of its resistance to post-weld, or strain-age, cracking during heat treatment.

These materials may be rolled through a wire mill to create different wire profiles for sectors like aerospace and oil & gas thanks to the shaping properties of Inconel alloy. In addition, they can be used to make bellows, springs, seal rings, and honeycombs. In addition, they are used as high performance fastener alloys in harsh environments, such as those where corrosion is likely.

Common Applications of Inconel 625 Tubing and 718 Tubing:

It is possible to employ Inconel 718 and 625 in various production applications. Along with round, flat, and square wire, product forms also include strip, ribbon, and curved wire. Interestingly, neither of these alloy varieties is frequently deep drawn.

The two superalloys can be used for many stamped parts, such as a sensor measuring device’s diaphragm. They are particularly handy when resistance to high temperatures and high pressures is required. Due to its significant strength in conditions of elevated temperatures and corrosion, as well as its resistance to oxidation, Inconel 625 tubing while naming specifics is utilized for flexible metal hoses, heat exchangers, header bars, as well as marine components.

 Industries that Use Inconel 625 Tubing and 718 Tubing:

Inconel 718 tubing were first used in the aircraft industry and have since spread throughout that sector. One study claims that the alloy accounts for more than 30% of the finished component mass of a modern airplane engine. An obvious application for a high temperature alloy that can withstand the extreme pressure, corrosive atmosphere, and thrust of burning jet fuel is in aircraft engines.

Similar high-stress conditions are produced for component alloys in automobile engines. The usage of a superalloy with great formability, supplied by the nickel content, benefits numerous engine components. An Inconel alloy can maintain the strong corrosion resistance required to ensure long-term durability while also keeping the unique shape needs of applications in the car engine.

Inconel 625 tubing has a lot of uses in the marine industry as well because of its corrosion resistance, particularly in settings with sea salt. This covers requirements for the oil and gas sector, such as tieback on underwater lines for downhole drilling. Other products such as telecommunications cables, propeller blades, and wire ropes can all be made out of inconel 625 and used in saltwater settings.


  • The primary benefit of the solid solution reinforced Inconel 625 tubing possess superior corrosion resistance.
  • The main characteristic of precipitation-strengthened Inconel 718 is its extremely high strength.
  • Both alloys have distinct purposes and cannot be substituted for one another.

Inconel 625 or 718 Tubing- Which Is Best for Your Application?

by Renine Metalloys time to read: 3 min