Ball bearings WIB - Technical information

TECHNICAL INFORMATION

Ring and ball material

The material used for ball bearing components must have good wear resistance, show good resistance to shock loads and to corrosion as well as a good dimensional stability.

Chrome steel 100 Cr6 for ball bearings is used for the production of rings and balls for standard WIB ball bearings. The 100 Cr6 rings, having been subjected to special heat treatment, have a hardness of 60 to 64 HRC, the balls of 62 to 65 HRC.

Stainless steel is also used by WIB, mainly for the manufacture of ultra-light (618xx and 619xx) and special bearings. The rings are made of X 65 Cr 13 (ACD 34) and the balls of X 105 CrMo 17 (440 C) stainless steel. They have a minimum hardness of 58 HRC after heat treatment.

For specific applications, special steels with particular properties may be used. For example, it is possible to use X 155 CrVMo 12.1 (DIN 1.2379) steel for the outer ring of a bearing requiring very high wear resistance of the contact surfaces.

Hybrid bearings may be obtained by associating rings and balls of 100 Cr6 steel, stainless steel or ceramic. The ceramic balls have a hardness of approximately 80 HRC. They increase the wear and corrosion resistance, allow a higher limiting speed and reduce the bearing noise as well as deformations. The result is better stability of the initial clearances and an increase of the ball bearing service life. Ceramic balls also provide better thermal and electrical insulation.

The 100 Cr6 steel rings produced by WIB are stabilized by annealing after hardening and can be used at temperatures up to 150°C.

Other stabilization methods for specific applications are available on request. They are described in the chapter entitled Heat Treatment

Chemical composition of steels used for standard ball bearings:

	Materials	Standards	Chemical Composition (%)
	Materials	Standards	C	Si	Mn	P	S	Cr	Mo
	100 Cr6	DIN 1.3505 JIS SUJ2 SAE 52100	0.90 -1.05	0.15 -0.35	0.25 -0.45	< 0.030	< 0.025	1.35 -1.65	--
	X65 Cr13 (ACD 34)	DIN 1.4037	0.60 -0.80	< 0.35	0.60 -0.70	< 0.030	< 0.020	12.50 -13.50	--
	X105 CrMo17 (440C)	DIN 1.4125 JIS SUS 440C AISI 440C	0.95 -1.20	< 1.00	< 1.00	< 0.040	< 0.030	16.00 -18.00	0.40 -0.80
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