What Is Metal Aging?

If the term “metal aging” has you thinking of the gray-haired, black-clad fans at a Tool concert, you’re probably not alone—but when it comes to metallurgy in Gastonia, SC, metal aging is a process used to speed up metallurgical changes in metal alloys. Here’s what metal aging can accomplish in your next project.

The basics of metal aging

Metal aging is used on solution heat treated alloys in order to increase their strength and hardness, while reducing their ductility. This can be done naturally—simply by letting the metal alloy hang out for years on end—or it can be done artificially.

When a metal ages, it forms metal precipitates with the help of super-saturated alloying elements. These block dislocations in the metal, which is what makes it stronger, harder and less ductile. Artificial metal aging is accomplished by heating a solution heat treated alloy. The temperature has to be under the recrystallization point, but high enough to form precipitates a lot faster. As soon as the precipitates are the appropriate size, the metal is rapidly cooled to prevent further enlargement.

Which kind of metals can be aged?

As long as a metal alloy is solution heat treatable, it can be aged. The most popular choices include stainless steel, aluminum, copper and other metal alloys. All of these alloys are capable of becoming incredibly hard and strong through the aging process. Even copper, which is usually soft and ductile, can be transformed through the metal aging process. It becomes a lot harder and stronger—but also quite brittle. You should also be able to age magnesium, nickel and titanium, as long as those alloys are solution heat treatable.

Can a metal be overaged?

It’s entirely possible to overage a metal. If you work the metal past the ideal precipitate size, the resulting alloy will actually reduce its strength and hardness. This can happen when you try welding or cold working the alloy. It also occurs if you heat the metal up past the target precipitate size. You may be able to artificially age the metal again, which could return its strength and hardness, but it’s smart to consult with a metallurgist before making any decisions.

How do I know if my metal should be aged?

If you have a metal project where pieces need to be strong, hard and less ductile, metal aging in Gastonia, NC could be the right process for you. However, there are other processes that can achieve similar effects. For example, flame and induction hardening, annealing and quenching are all ways that metallurgists harden metals. The right process depends on exactly what kind of metal you’re working with, what your ultimate goals may be and what your metallurgist recommends.

Talking to the team at J.F. Heat Treating Inc. is the best way to find out what kind of processes are best suited to your projects. We have over 40 years of experience in the business—get in touch with us today to learn more and get a quote.

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