Simple past tense and past participle of caseharden.(verb)
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Use "casehardened" in a sentence
"Of the lot the upper end gun is the Woodcock, color casehardened, single selective trigger, ejectors on the 12 & 20, screw in choketubes."
"Featuring polypropylene felt soles tapped to accept Chota's casehardened steel cleats, each pair of shoes comes with 28 cleats, which are easily installed or removed-depending on wading conditions-with a 1/4 inch nut driver."
"An endeavor was next made to substitute a tougher metal for casehardened iron, and steel was naturally thought of."