air-hardening

[ air-hahr-dn-ing ]

adjective

, Metallurgy.

1. noting any metal, especially alloy steel, that can be hardened from above its transformation point by cooling in air.

air hardening

noun

1. a process of hardening high-alloy steels by heating and cooling in a current of air Compare oil hardening

Word History and Origins

Origin of air-hardening¹

First recorded in 1905–10

Example Sentences

The connecting rods are of “H” section, machined all over from forgings of a special air-hardening chrome nickel steel which, after being heat treated has a tensile strength of 280,000 pounds per square inch.

From Project Gutenberg

Air-hardening Steels.—These steels are recommended for boring, turning and planing where the cost of high-speed seems excessive.

From Project Gutenberg

Owing to the air-hardening property of the steel, the drop-forgings should be trimmed while hot.

From Project Gutenberg

The gear steel specified is of the air-hardening type.

From Project Gutenberg

Page 116 Annealing Work.—With the exception of several of the higher types of alloy steels, where the percentages of special elements run quite high, which causes a slight air-hardening action, the carburizing steels are soft enough for machining when air cooled from any temperature, including the finishing temperature at the hammer.

From Project Gutenberg