Definition
A category of low-alloy steel that has been specially formulated and heat-treated to achieve tensile strength significantly greater than ordinary carbon steel, while retaining enough toughness to resist cracking under load. In aircraft construction it is used for highly stressed structural parts such as landing gear components, engine mounts, and bolts that must carry heavy loads without failure.
Plain English
A type of steel made and treated to be much stronger than normal steel, used for aircraft parts that have to take a lot of force without breaking.
Context Anchor
Seen in aircraft maintenance, structural repair, corrosion inspection, and parts replacement discussions.
Why Pilots Care
Critical parts made from it maintain integrity under extreme flight and landing forces, directly affecting safety and preventing catastrophic failure.
Intuition Check
Do not assume high-strength steel just means “thick steel” or “heavy steel.” It means steel made and treated to carry very high loads for its size.
Example Sentence 1
The landing gear trunnion is forged from high-strength steel to handle the impact loads of touchdown.
Example Sentence 2
During preflight, the pilot checked for corrosion on exposed high-strength steel fittings in the wing structure.