Fleet Readiness Center Southwest’s (FRCSW) heat treating shop in Building 472 is the hub for the reworking of metallic and structural aircraft components that have experienced damage from hard landings or mishaps.
The heat treating process is used to achieve a specific hardness in a metal. Repairing an F/A-18 Hornet wing, for example, would require removing the skins and heating the wing’s ribs and frame work to straighten them to specifications.
Artisans in the heat treating shop primarily work with aluminum, but also process steel and titanium components of the airframes serviced by FRCSW.
The shop also repairs non-aircraft items like tooling and ground
The majority of the shop’s workload originates from the command’s manufacturing program, and consultations with the engineering department are common for unique structural repairs and issues.
Heat treating repairs begin with a series of hardness tests and readings to determine the degree of damage to the part. The method of heat treating depends on the metal.
The shop uses computer-controlled furnaces or ovens that deliver varying levels of heat; salt bath for medium heat; and solution heat treating.
Primarily used in treating aluminums, the salt bath is a quenching or cooling down process of the metal to a certain degree at a rapid temperature.
Solution heat treating places the metal at a high temperature for a specific amount of time then quenches it in oil, water, or air which develops the hardness.
To prevent metals from becoming too brittle, artisans use a procedure called “annealing.”
As aircraft age, more of their components require heat treating for making the metals harder.
For newer aircraft components, the shop uses drop bottom ovens. Metals are placed in baskets or on a grid, and positioned under the oven and attached to a lift mechanism.
The baskets or grid are lifted into a chamber and the doors, located on the bottom, are closed as the heating process begins. At a set time, the doors open and the materials are lowered into a waiting quench tank.
FRCSW’s heat treating shop and is the only naval facility of its kind on the West Coast.