What is "case-hardened"

Usage examples of "case-hardened".

The hull rang as the first hypervelocity missile struck the case-hardened steel of the bridge.

The only notable break that occurred anywhere in that gleaming case-hardened rhomboid was the small square panel in one side where the combination lock showed narrow segments of its four milled and lettered chrome-steel wheelsand even those were matched and balanced into their aperture so infrangibly that a bacillus on hunger strike would have felt cramped between them.

But the case-hardened steel would turn any ordinary sword, spear or arrow, and weighed no more than a second layer of wood.

Grim was the only word to describe it, the set of his jaw like case-hardened steel.

The case-hardened steel rang out against the chipped wooden stock of the Kentucky musket.

The walls were brownstone-the hardest building material other than granite or marble to tunnel or blast through-and the windows were blocked with bars that looked like old iron but that Stephen knew were really case-hardened steel and would be wired with motion or decibel sensors or both.

The frangible bullets in their Sigs would be no use against the door's case-hardened steel panels.

The quad of heavily armed hammermen, the foreriders with their case-hardened spears, and the swordsmen with their blades of blue steel were here t solely to guard the wagon.