Material
    The ring and balls of SFB bearings are made of refining bearing steel GCr15(AISI 52100),the retainer are punched from brass strip(H62)or top quality cold-rolled steel strip(SPCC BQB402)and reinforced engineering plastics are available if necessary.The shield is made of imported special material or (SPCC JISG3141)stainless steel (ICr18Ni9)strip and the bune-N rubber seal with phosphatizing steel skeleton are hot pressed
    The stainless steel bearing"s ring and balls refining stainless 9Crl8(AISI 440C).
    The chemical composition of bearing steel and stainless steel are listed as follows:

Steel No	C%	Si%	Mn%	S%	P%	Cr%
GCr15	0.95-1.05	0.15-0.3	0.25-0.45	＜0.025	＜0.025	1.3-1.6
9Cr18	0.90-1.05	＜0.8	＜0.8	＜0.04	＜0.03	16-19

Packing
    Generally SFB Bearing is to be packed in the plastic pipes or the thin membrane bags(10 sets).then to be packed into the medium size Paper Box(50 sets or 100 sets).Then all to be packed in to the carton as the external packing Small. The users who have any requirements in packing may write them down in the contract.     Tolerance
    SFB bearings are of motor class bearings and the common tolerance is shown on the attached data sheet.For any special tolerance indicated on the purchase order,custom-built service is available.
Comparisiion Table Of Tolerance Grade:

Country	Standard	Tolerance Grade
China	GB	0	6	5	4
American	ANSI	ABEC-1	ABEC-3	ABEC-5	ABEC-7
	ISO	0	6	5	4
Germany	DIN	P0	P6	P5	P4
Japan	JIS	P0	P6	P5	P4

Radial Play
    The radial play of bearings is specified as five groups as follows in accordance with Chinese national standard GB4604:

bearing bore(mm)		group 2-C2		C0basic group C0		group 3-C3		group 4-C4		group 5-C5
bearing bore(mm)		group 2-C2		C0basic group C0		group 3-C3		group 4-C4		group 5-C5
over	inct.	min	max	min	max	min	max	min	max	min	max
over	inct.	min	max	min	max	min	max	min	max	min	max
2.5	6	0	7	2	13	8	23	14	29	20	37
6	10	0	7	2	13	8	23	18	33	25	45
10	18	0	8	3	18	11	25	20	36	28	48
18	24	0	10	5	20	13	28	23	41	30	53
24	30	1	11	5	20	13	28	28	43	40	64
30	40	1	11	6	20	15	33

    Special radial play or shaft face clerance requirement could be made as specified in orders.
Vibratro and Noise
    Deep Groove Ball Bearing Accelerating Vibration Value(dB).See Table 1
    Deep Groove Ball Bearing Accelerating Vibration Value( μm/s).See Table 2
    Table 1 Single Bearing Vibration speed Grade can not be over the following Values

bearing bore mm	（0）				（2）					（3）
bearing bore mm	Z	Z1	Z2	Z3	Z	Z1	Z2	Z3	Z4	Z	Z1	Z2	Z3	Z4
3	35													-
4	35	34	32	28	36	35	32	30	-	37	36	33	31	-
5	37	34	32	28	36	35	32	30	-	37	36	33	31	-
6	37	36	34	30	38	37	34	32	-	39	37	35	33	-
7	39	36	34	30	38	37	34	32	-	39	37	35	33	-
8	39	38	35	31	40	38	36	34	-	-	-	-	-	-
9	41	38	35	31	40	38	36	34	-	-	-	-	-	-
10	43	40	36	32	42	40	37	35	-	-	-	-	-	32
12	44	42	38	33	44	42	39	35	30	46	44	40	37	32
15	45	43	39	34	45	43	39	35	30	47	45	40	37	33
17	46	44	40	35	46	44	41	36	31	48	46	42	38	33
20	47	44	40	35	47	45	41	36	31	49	47	42	38	34
25	48	45	41	36	48	46	42	38	33	50	48	43	39	37
30	49	46	42	38	49	47	43	40	36	51	49	44	41	38
35	51	47	43	39	50	48	44	41	37	52	50	45	42	40
40	53	49	45	41	52	50	46	43	39	54	52	47	44	41
45	55	51	46	42	54	52	47	44	40	56	54	49	45	44
50	57	53	48	45	56	54	49	46	43	58	56	51	47	46
55	59	54	50	47	58	55	51	48	45	60	57	53	49	48
60	61	56	52	49	60	57	53	50	47	62	59	54	51	50
		58	54	51	62	59	54	51	48	64	61	56	53

Table 2 Single Bearing Vibration Speed Grade Allowed The Limit Value μm/s

Bore Diameter	V			V1			V2			V3
Bore Diameter
d mm
	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand
	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand	Low Brand	Medium Brand	High Brand
5	110	72	60	90	60	50	58	36	30	35	21	18
6	110	72	60	90	60	50	58	36	30	35	21	18
7	130	96	80	110	80	65	72	48	40	44	28	24
8	130	96	80	110	80	65	72	48	40	44	28	24
9	130	96	80	110	80	65	72	48	40	44	28	24
10	160	120	100	140	100	85	90	60	50	55	35	30
12	160	120	100	140	100	85	90	60	50	55	35	30
15	210	150	120	180	130	100	110	78	60	65	46	35
17	210	150	120	180	130	100	110	78	60	65	46	35
20	260	190	150	220	160	125	130	100	75	80	60	45
22	260	190	150	220	160	125	130	100	75	80	60	45
25	260	190	150	220	160	125	130	100	75	80	60	45
28	260	190	150	220	160	125	130	100	75	80	60	45
30	300	240	190	250	200	160	150	120	100	90	75	60
32	300	240	190	250	200	160	150	120	100	90	75	60
35	300	240	190	250	200	160	150	120	100	90	75	60
40	360	300	260	300	250	220	180	150	130	110	90	80