Steel

Steels are a class of iron alloys which are generally suitable for structural, high-temperature, or tooling applications.

Compositions

Name	Uses	Components (% by mass, balance is Fe)							Impurity limits		Character
		C	Mn	Cr	Ni	W	Co	Si	P	S
Low Carbon		0.05-0.3
High Carbon		0.6-2.0
Cast Iron	Cast structural parts, bearings	≥2.0
Invar	Pendulae, Instruments	0			64						Low thermal expansion (1.2ppm/°K)
Elinvar	Springs	0		12	36						Low thermal elasticity change
Kovar	Borosilicate glass/Metal joints	<0.1			29		17	0.2			Glass-matched thermal expansion
1085	Baling Wire	0.0085	0.0085						0.0003	0.0005
Mushet	Early High Speed Steel	0.0185	0.0250			0.0900			—	—
304	Generic Stainless Steel	0.0800	0.0200	0.1800	0.0800			0.0100	0.0045	0.0003	Chemically inert (relatively)