1-1. High carbon chromium bearing steel

As material of bearing rings and rolling elements, high-carbon chromium bearing steel specified in JIS G4805 is used. The steel is hardened and tempered before use.

SUJ2 Most common bearing steel. SUJ3 Has more manganese than SUJ2 and therefore has better tempering characteristics. Used for medium-size and large-size bearings. SUJ5 Made by adding molybdenum to SUJ3, improving tempering characteristics further. It is used for thick-section products and very large bearings.

Table 10-1 Chemical composition of high carbon chromium bearing steel

Standard	Code	Chemical composition (%)
		C	Si	Mn	P	S	Cr	Mo
JIS G 4805	SUJ 2	0.95 - 1.10	0.15 - 0.35	Not more than 0.50	Not more than 0.025	Not more than 0.025	1.30 - 1.60	-
	SUJ 3	0.95 - 1.10	0.40 - 0.70	0.90 - 1.15	Not more than 0.025	Not more than 0.025	0.90 - 1.20	-
	SUJ 5	0.95 - 1.10	0.40 - 0.70	0.90 - 1.15	Not more than 0.025	Not more than 0.025	0.90 - 1.20	0.10 - 0.25
SAEJ 404	52100	0.98 - 1.10	0.15 - 0.35	0.25 - 0.45	Not more than 0.025	Not more than 0.025	1.30 - 1.60	Not more than 0.06

[Remark]

As for bearings which are induction hardened, carbon steel with a high carbon content of 0.55 to 0.65 % is used in addition to listed in this table.