Chromal

Chromal 

the general name of a group of refractory iron-base alloys that contain 17 to 30 percent Cr and 4.5 to 6.0 percent Al. Chromals have an uncommon combination of high heat resistance (up to 1400°C) and high electrical resistivity (1.3 to 1.5 uohm-m). The melting point varies from 1500° to 1510°C, and the density, from 7.15 to 7.30 g/cm³.

Chromals, like nichromes, are common materials in technology used in the form of wires and strips in the production of the heating elements of high-temperature electric furnaces. Although less expensive and more heat-resistant than the nichromes, they are more difficult to produce and require special service conditions because of the low strength at temperatures above 1000°C, embrittlement while in service, and the ability to interact chemically with the vapors and oxides of certain metals that are widely used in practice. Chromals exhibit good resistance to heat in air, hydrogen, and an oxidizing atmosphere containing sulfur and carbon.

In the USSR, 0Kh23Iu5A, 0Kh27Iu5A, and other types of chromals are produced. The best known chromals manufactured abroad are the alloys Kanthal and Megapyr.

REFERENCE

Pretsizionnye splavy: Spravochnik. Moscow, 1974.