Inconel vs Stainless Steel: Which is Stronger?

Many of Marlin Steel’s customers want to have the absolute strongest metal possible for their custom wire forms. This often leads to questions comparing two specific metals—such as, “Is Inconel a form of stainless steel?” (it is similar, but different) and, “Is Inconel stronger than steel?” The answer is: it depends on what you mean by "stronger." Strength can be measured by tensile strength, corrosion resistance, or even melt resistance.

Why Comparing Inconel Vs Stainless Steel Can Be Complicated

When comparing stainless steel vs inconel, it is important to remember that there are different formulations for each. The variants of stainless steel have drastically different tensile strength, recommended operating temperature, and resistance to specific corrosives. For example, grade 316 stainless steel tends to have a higher resistance to chlorides than 304 stainless steel (but also has a higher cost on average).

Additionally, certain treatment and forming methods may affect the tensile strength of a metal. For example, according to data from specialmetals.com, the tensile strength of an “as-rolled” bar of Inconel 625® is 120-160 ksi (827-1103 MPa), while a “Solution-Treated” bar has 103-130 ksi (714-896 MPa) of tensile strength.

You might have noticed that both of these tensile strength ratings are given as a range instead of a specific number. This is because the strength of a metal may vary somewhat depending on the precise proportion of ingredients in it—a slight variation in carbon, nickel, or iron content can significantly alter the final product’s strength.

So, is Inconel Stronger Than Steel?

Here’s a quick comparison of Inconel vs stainless steel to help answer the question of which is stronger:

Alloy

Inconel 625®

304 Stainless Steel

Tensile Strength

103-160 ksi (714-1,103 MPa)

73.2 ksi (505 MPa)

Melting Point

2,350-2,460°F (1,290-1,350°C)

2,550-2,650˚F (1,400-1,455˚C)

Operating Temperature

1,800°F (982°C)

1,697°F (952°C)

Corrosion Resistance

Resistant to oxalic acid and high-temperature oxidation

Excellent all-around resistance—though it’s vulnerable to chlorides and high-temp oxidation

Inconel 625® has a higher tensile strength than grade 304 stainless steel, and does a better job of maintaining that strength at higher operating temperatures.

Additionally, though the melting point of this particular type of Inconel is lower than that of 304 stainless steel, it has a higher operating temperature limit. This is because Inconel is stronger than stainless steel at high temperatures, while being more resistant to oxidation and scaling as well.

However, there are specific chemicals that the stainless steel might be better at resisting than Inconel—such as sulfuric acid. So, the choice of which of these two metal alloys to use will depend on the specific application they’ll be used for.

Inconel alloys tend to be better for heat treating applications and other high-temperature processes. Meanwhile, stainless steel alloys are often suitable for sterile manufacturing or medical applications (or any application involving corrosives).

Need help choosing the right metal alloy for your needs? Reach out to the Marlin Steel team today for more information about Inconel, stainless steel, and other custom wire form materials.