v. [f. CASE sb.2 (in locative constr.) + HARDEN v.] trans.
1. To harden on the surface; spec. to convert iron superficially into steel by partial cementation.
1677. Moxon, Mech. Exerc. (1703), 56. Rasps have formerly been made of Iron and Case-hardned, because it makes the outside of them hard.
1864. Daily Tel., 11 Aug., 4/6. Till the ship-men find some way of case-hardening their plates.
1881. Greener, Gun, 253. Some work is case-hardened by plunging when at a red heat into a solution of prussiate of potass.
2. fig. To harden in constitution or spirit, so as to render insensible to external impressions.
1713. Steele, Guardian, No. 95, ¶ 15. Adieu, old Fellow…: E’en get thy self Case-harden’d.
1771. Smollett, Humph. Cl., III. 26 Oct. In order to case-harden the constitution.
1871. R. H. Hutton, Ess. (1877), I. 100. He can so easily case-harden his spirit against the supernatural pain.
