case-harden

A blacksmith case-hardens a piece of iron in his forge.

Definition

1. Verb:
   • To harden the surface of (metal): "case-harden" refers to a metallurgical process in which the surface layer of a metal, typically iron or steel, is made harder than the interior. This is often achieved by adding carbon (carburizing) or through other chemical treatments.
   • Figuratively, to make callous or insensitive: In a metaphorical sense, "case-harden" means to make someone emotionally hardened, unfeeling, or resistant to influence through repeated exposure to harsh experiences.

Usage Examples

• Literal (metallurgy):

  • The blacksmith will case-harden the blade to improve its durability. (The smith will harden the surface of the steel blade.)
  • This factory specializes in case-hardening gears for industrial machinery. (The factory treats the metal gears to create a hard outer layer.)

• Figurative (emotion):

  • Years of rejection had case-hardened him against criticism. (Repeated negative experiences made him emotionally insensitive.)
  • The trauma of war case-hardened the soldiers, leaving them numb to violence. (The soldiers became callous due to prolonged suffering.)

Advanced Usage

• "to be case-hardened by experience": to become emotionally tough or cynical due to life circumstances.

  • She was case-hardened by a childhood of poverty. (Her difficult upbringing made her resilient and unemotional.)

• "case-hardened steel": steel treated through the case-hardening process.

  • The tools are made from case-hardened steel for extra strength. (The steel has a hardened outer layer.)

Variants and Related Words

• Case-hardening (n): the process or result of hardening the surface of metal.

  • Case-hardening improves wear resistance. (The treatment makes the metal last longer.)

• Case-hardened (adj): treated by case-hardening; also, emotionally hardened.

  • He is a case-hardened veteran of corporate politics. (He is emotionally tough from years in business.)

Synonyms

• Temper: to harden metal by heating and cooling.
• Season: to make wood or metal more durable by exposure; figuratively, to make experienced.
• Callous: (figurative) to make unfeeling or insensitive.

Phrasal Verbs

• Harden off: (related) to gradually accustom a plant to outdoor conditions.
  • You should harden off seedlings before transplanting. (Adapt them to the environment.)
    (Note: This is not a direct phrasal verb for "case-harden" but shares the concept of gradual hardening.)

Related Idioms

• Harden one's heart: to become emotionally cold or unkind.
  • He hardened his heart against pleas for mercy. (He refused to feel sympathy.)
    (Note: This idiom captures the figurative sense of "case-harden" but uses "harden" alone.)