Quenching (Metalwork in Aircraft)

Quenching (Metalwork in Aircraft) refers to the rapid cooling of heated metal, typically after heat treatment, to alter the metal's microstructure and achieve mechanical properties like increased strength, hardness, and durability. This process is widely used in the aerospace industry to enhance material performance for critical aircraft components.

Furnaces are adapted for heat treatment of the various metallurgical states of aluminium alloys: T4, T5, T6, T7 and T8. Wing leading edges, air intake lips, exhausts, tail panels, wing panels, fuselage parts, rivets, etc.

Load video

YouTube

YouTube might collect personal data. Privacy Policy

ContinueDismiss

Purpose

Quenching is a key step in heat treating metals, used to freeze the microstructure in a desired state by rapidly cooling from a high temperature. This improves material properties such as hardness, strength, and fatigue resistance.

Process

• The metal is first heated to a specific temperature—often above its recrystallization point but below melting.
• It is then rapidly cooled using a quenching medium such as water, oil, polymer solution, air, or inert gas.
• This "freezes" the desired microstructure, locking in changes that improve the material's mechanical behavior.

Why it's used in aircraft

• Aircraft components—especially aluminum alloys and steels—need precise strength and hardness characteristics for structural integrity and flight performance.
• Engineers can tailor these properties by controlling the cooling rate during quenching.
• Quenching strengthens aircraft parts such as steel gears or aluminum alloy wing panels.

Types of Quenching

• Water Quenching: Uses water for rapid cooling.
• Oil Quenching: Uses oil, which cools slower than water, reducing thermal stress.
• Air Quenching: Uses air or inert gases—ideal for parts sensitive to liquid immersion.
• Salt Bath Quenching: Uses molten salt baths to provide uniform heat transfer and controlled cooling.

Benefits

• Enhanced material hardness and tensile strength.
• Improved resistance to wear.
• Increased fatigue life of aircraft components.

Considerations

• Too-rapid cooling may cause distortion or cracking in some geometries or alloys.
• The choice of quenching medium affects the outcome and must align with the alloy’s properties.
• Post-quenching tempering is often used to reduce brittleness and refine toughness.

References

• Sat Thermique – Aerospace Heat Treatment Applications