High-chromium Or Rust-proof Steel

: The Working Of Steel

High-chromium, or what is called stainless steel containing from

11 to 14 per cent chromium, was originally developed for cutlery

purposes, but has in the past few years been used to a considerable

extent for exhaust valves in airplane engines because of its resistance

to scaling at high temperatures.


Carbon 0.20 to 0.40

anese, not to exceed 0.50

Phosphorus, not to exceed 0.035

Sulphur, not to exceed 0.035

Chromium 11.50 to 14.00

Silicon, not to exceed 0.30

The steel should be heated slowly and forged at a temperature above

1,750 deg.F. preferably between 1,800 and 2,200 deg.F. If forged at temperatures

between 1,650 and 1,750 deg.F. there is considerable danger of rupturing

the steel because of its hardness at red heat. Owing to the

air-hardening property of the steel, the drop-forgings should be

trimmed while hot. Thin forgings should be reheated to redness

before trimming, as otherwise they are liable to crack.

The forgings will be hard if they are allowed to cool in air. This

hardness varies over a range of from 250 to 500 Brinell, depending

on the original forging temperature.