caseharden

[ keys-hahr-dn ]

verb (used with object)

1. Metallurgy. to make the outside surface of (an alloy having an iron base) hard by carburizing and heat treatment, leaving the interior tough and ductile.
2. to harden in spirit so as to render insensible or insensitive to external impressions or influences; make callous.

Word History and Origins

Origin of caseharden¹

First recorded in 1670–80; case ² + harden

Example Sentences

I have a peculiar kind of steel which I cannot harden by fire and water, neither will it caseharden by prussiate of potash.

From Project Gutenberg

How to Caseharden Large Pieces of Steel.—A box of cast or wrought iron should be provided large enough to hold one or two of the pieces, with sufficient room all around to pack well with the casehardening materials, which may be leather scrap, hoof shavings, or horn shavings, slightly burned and pulverized, which may be mixed with an equal quantity of pulverized charcoal.

From Project Gutenberg

The same salt may be used to caseharden wrought iron.

From Project Gutenberg