The Use of Heat Treated Bolts in Aerospace

The Use of Heat Treated Bolts in Aerospace

Ever heard the expression “failure is not an option”? It is twice as true in aerospace. That’s why heat treated bolts are necessary.

Aerospace bolts are one of the most critical components in any aircraft, rotorcraft or spacecraft. They must meet incredibly demanding requirements in order to perform in such extreme environments.We create aerospace bolts from many superalloys and exotic materials. To further enhance the performance characteristics of some bolts, we must heat treat them.

Here’s an introduction to heat treated bolts in aerospace and the heat treatment process.

Kinds of Heat Treatment

While aerospace bolts are made of a plethora of exotic materials (superalloys like Waspaloy and Inconel 718; nickel alloys like Monel and K-Monel, titanium, etc.), many are made of aluminum and its alloys. Though there’s nothing exotic about aluminum, it makes up 50% of the aerospace materials market. Numerous aluminum alloys exist, and some like aluminum 7075 are nearly as strong as steel. All aluminum alloys are classified as either heat treatable or not heat treatable. Heat treated bolts are put through one of the following processes to achieve optimal performance in their given applications:

Quenching – Quenching can be called the most essential step in heat treatment. It is designed to create a super-saturated solid solution at room temperature. Various quenching mediums are used, but water is the most common and most effective. Some heat treated bolts, particularly those made of superalloys, must be quenched using gas quenching. Most heat treatable aluminum alloys are artificially aged following quenching.

Annealing – Annealing is a process used to relieve stresses, to stabilize properties and dimensions, to increase ductility, and to soften strain-hardened and heat treated superalloys — but at a loss of strength. Many kinds of annealing exist, and different processes are used depending on the alloy.

Solution heat treatments – Solution heat treatment is achieved by heating and holding aluminum and alloys to a temperature just below their eutectic melting temperature. This causes the alloy to become a homogenous solid solution. Solution heat treatment is a complicated process. Overheating and underheating can cause a loss in tensile strength, fracture toughness, and ductility.

Precipitation heat treatments – Precipitation heat treatments provide hardening by precipitation constituents from solid solution. Precipitation heat treatment involves a complicated system of time and temperature dependant changes to achieve the desired results.

Age hardening – Age hardening can be achieved in two ways: naturally and artificially. Natural age hardening refers to the hardening that occurs naturally after quenching. The degree of hardening depends on the alloy. Artificial age hardening refers to the process of reheating quenched materials to around 212 degrees Fahrenheit and 424 degrees Fahrenheit.

Procure Heat Treated Bolts from Aerospace Manufacturing

Aerospace Manufacturing creates high strength, close tolerance heat treated bolts to AN, MIL, MS, NA, NAS standards of the finest super alloys such as Inconel, A-286, Waspaloy, Titanium, and other exotic materials.

We are AS9100 and ISO:9001 accredited, QSLM approved and a Phillips Screw licensee.

To find exactly the heat treated bolts you need, search our extensive inventory. Getting a quote has never been easier!