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Selection of Bearing Type

Bearing Material

Rings(cups & cones) & Rolling elements
SFT bearing rings(cups & cones), balls & rollers are made of GCr15 high carbon chromium bearing steel
This steel No. is equal to the AISI 52100(U.S.A.), DIN 100Cr6(Germany), JIS SUJ2(Japan) etc.

Chemical composition of GCr15 steel:

Steel No.

Chemical composition %

GCr 15

C

Si

Mn

P

S

Cr

Mo

Cu

Ni

0.95-1.05

0.15-0.35

0.25-0.45

≤0.027

≤0.02

1.40-1.65

-

≤0.25

≤0.30


Contrast of steel no. in different countries

Country

China

ISO

U.S.A.

Japan

Germany

France

Sweden

Standard

GB

AISI

JIS

DIN

NF

Steel No.

GCr15

683/XVLL1

52100

SUJ2

100Cr6

100C6

SKF3


Hardness
Hardness of bearing rings(cups & cones) & rolling elements is HRC60
HRC65.

Retainers
SFT standard bearing retainers are made from cold rolled carbon steel. However, in cases of heavy duty, corrosive environment,misalignment and high speed operation, brass, stainless steel, nylon or phenolic resins will be used upon request.

Seals & Shields
SFT shields also employ carbon steel as standard.
Buna Nitrile is the standard and mostly common used material for SFT seals. Also, in order to meet the requirements of high temperature operation and compatibility with grease, a variety of other sealing materials are also applied to the seals.

Lubrication
Standard grease and oil are applied to SFT bearing products
SFT can also use special pointed brand grease or oil upon request

Tolerance

SFT bearing tolerance standard accords with Chinese national standard GB/T307(equal to ISO492)
The following are the contrast tables of Chinese national standard with the foreign standards.

Contrast of tolerance class for radial bearings in different countries(except tapered roller bearing)

Country

Standard

Tolerance class

China

GB/T307

0 (G)

6 (E)

5 (D)

4 (C)

2 (B)

ISO

ISO492

0

6

5

4

2

Sweden

SKF

0

P6

P5

P4

P2

Germany

DIN 620/2

P0

P6

P5

P4

P2

U.S.A.

ANSI B3.14

ABEC1

ABEC3

ABEC5

ABEC7

ABEC9

Japan

JIS B1514

0

6

5

4

2


Contrast of tolerance class for tapered roller bearing(metric size) in different countries

Country

Standard

Tolerance class

China

GB/T307

0

P6x

 

P5

P4

 

ISO

ISO492

0

6x

 

5

4

 

Sweden

SKF

0

CLN

 

P5

 

 

U.S.A.

ANSI

K

 

N

C

B

A

Japan

JIS

0

6x

6

5

4

 


Contrast of tolerance class for tapered roller bearing(inch size) in different countries

Country

Standard

Tolerance class

China

SFT

4

 

3

 

 

ISO

ISO492

4

 

3

0

00

Sweden

SKF

0

 

CL3

CL0

 

U.S.A.

ANSI

4

2

3

0

00

The standard manufacturing tolerance of SFT bearing is Class 0. Other tolerance grade can be supplied upon request

Tolerance of Class 0 radial bearing

Inner ring

d

dmp

Vdp

Vdmp

Bs

B1s

VBs

Kia

over

incl.

high

low

Dimension series

max

high

low

high

low

max

max

mm

µm

8, 9

0, 1

2, 3, 4

µm

µm

µm

µm

µm

max (µm)

2.5

10

0

-8

10

8

6

6

0

-120

0

-250

15

10

10

18

0

-8

10

8

6

6

0

-120

0

-250

20

10

18

30

0

-10

13

10

8

8

0

-120

0

-250

20

13

30

50

0

-12

15

12

9

9

0

-120

0

-250

20

15

50

80

0

-15

19

19

11

11

0

-150

0

-380

25

20

80

120

0

-20

25

25

15

15

0

-200

0

-380

25

25

120

180

0

-25

31

31

19

19

0

-250

0

-500

30

30

180

250

0

-30

38

38

23

23

0

-300

0

-500

30

40

250

315

0

-35

44

44

26

26

0

-350

0

-500

35

50

315

400

0

-40

50

50

30

30

0

-400

0

-630

40

60

400

500

0

-45

56

56

34

34

0

-450

0

-630

50

65

500

630

0

-50

63

63

38

38

0

-500

0

-800

60

70

630

800

0

-75

 -

 -

 -

 -

0

-750

 -

 -

70

80

800

1000

0

-100

 -

 -

 -

 -

0

-1000

 -

 -

80

90

1000

1250

0

-125

 -

 -

 -

 -

0

-1250

 -

 -

100

100

1250

1600

0

-160

 -

 -

 -

 -

0

-1600

 -

 -

120

120

1600

2000

0

-200

 -

 -

 -

 -

0

-2000

 -

 -

140

140

Outer ring

D

Dmp

VDp

VDmp

Cs

C1s

VCs

Kea

over

incl.

high

low

Dimension series

With oil seals

max

high

low

high

low

max

max

mm

µm

8, 9

0, 1

2, 3, 4

or shields

µm

µm

µm

µm

µm

max (µm)

6

18

0

-8

10

8

6

10

6

same as inner ring Bs, B1s, VBs

15

18

30

0

-9

12

9

7

12

7

15

30

50

0

-11

14

11

8

16

8

20

50

80

0

-13

16

13

10

20

10

25

80

120

0

-15

19

19

11

26

11

35

120

150

0

-18

23

23

14

30

14

40

150

180

0

-25

31

31

19

38

19

45

180

250

0

-30

38

38

23

 -

23

50

250

315

0

-35

44

44

26

 -

26

60

315

400

0

-40

50

50

30

 -

30

70

400

500

0

-45

56

56

34

 -

34

80

500

630

0

-50

63

63

38

 -

38

100

630

800

0

-75

94

94

55

 -

55

120

800

1000

0

-100

125

125

75

 -

75

140

1000

1250

0

-125

 -

 -

 -

 -

 -

160

1250

1600

0

-160

 -

 -

 -

 -

 -

190

1600

2000

0

-200

 -

 -

 -

 -

 -

220

2000

2500

0

-250

 -

 -

 -

 -

 -

250


Tolerance of Class 0 tapered roller bearing (metric size)

Cone and width

d

dmp

Vdp

Vdmp

Bs

Kia

Ts

T1s

T2s

over

incl.

high

low

max

max

high

low

max

high

low

high

low

high

low

mm

µm

µm

µm

µm

µm

µm

µm

µm

10

18

0

-12

12

9

0

-120

15

+200

0

+100

0

+100

0

18

30

0

-12

12

9

0

-120

18

+200

0

+100

0

+100

0

30

50

0

-12

12

9

0

-120

20

+200

0

+100

0

+100

0

50

80

0

-15

15

11

0

-150

25

+200

0

+100

0

+100

0

80

120

0

-20

20

15

0

-200

30

+200

-200

+100

-100

+100

-100

120

180

0

-25

25

19

0

-250

35

+350

-250

+150

-150

+150

-150

180

250

0

-30

30

23

0

-300

50

+350

-250

+150

-150

+150

-150

250

315

0

-35

35

26

0

-350

60

+350

-250

+150

-150

+150

-150

315

400

0

-40

40

30

0

-400

70

+400

-400

+200

-200

+200

-200

400

500

0

-45

45

34

0

-450

70

+400

-400

 

 

 

 

500

630

0

-50

50

38

0

-500

85

+500

-500

 

 

 

 

630

800

0

-75

75

56

0

-750

100

+600

-600

 

 

 

 

800

1000

0

-100

100

75

0

-1000

120

+750

-750

 

 

 

 

1000

1250

0

-125

 

 

0

-1250

120

+1000

-1000

 

 

 

 

1250

1600

0

-160

 

 

0

-1600

120

+1500

-1500

 

 

 

 

1600

2000

0

-200

 

 

0

-2000

120

+1500

-1500

 

 

 

 

Cup

D

Dmp

VDp

VDmp

Cs

Kea

over

incl.

high

low

max

max

high

low

max

mm

µm

µm

µm

µm

µm

18

30

0

-12

12

9

same as Bs

18

30

50

0

-14

14

11

20

50

80

0

-16

16

12

25

80

120

0

-18

18

14

35

120

150

0

-20

20

15

40

150

180

0

-25

25

19

45

180

250

0

-30

30

23

50

250

315

0

-35

35

26

60

315

400

0

-40

40

30

70

400

500

0

-45

45

34

80

500

630

0

-50

50

38

100

630

800

0

-75

75

55

120

800

1000

0

-100

100

75

120

1000

1250

0

-125

125

94

120

1250

1600

0

-160

160

120

120

1600

2000

0

-200

 

 

120

2000

2500

0

-250

 

 

120


Tolerance of Class 4 tapered roller bearing (inch size)

Cone

d

ds

over

incl.

high

low

mm

µm

 -

76.2

+13

0

76.2

101.6

+25

0

101.6

266.7

+25

0

266.7

304.8

+25

0

304.8

609.6

+51

0

609.6

914.4

+76

0

914.4

1219.2

+102

0

1219.2

 -

+127

0


Cup

D

Ds

Kia,Kea,Sia,Sea

over

incl

high

low

max

mm

µm

µm

 -

266.7

+25

0

51

266.7

304.8

+25

0

51

304.8

609.6

+51

0

51

609.6

914.4

+76

0

76

914.4

1219.2

+102

0

76

1219.2

 -

+127

0

76


Width

d

D

Ts

over

incl

over

incl

high

low

mm

µm

µm

 -

101.6

 -

 -

+203

0

101.6

266.7

 -

 -

+356

-254

266.7

304.8

 -

 -

+356

-254

304.8

609.6

 -

508

+381

-381

304.8

609.6

508

 -

+381

-381

609.6

 -

 -

 -

+381

-381

Tolerance of Class 0 tapered bore of radial bearing (tapered bore = 1:12)

d

dmp

Vdp

d1mp-dmp

over

incl

high

low

max

high

low

mm

µm

µm

µm

18

30

+21

0

13

+21

0

30

50

+25

0

15

+25

0

50

80

+30

0

19

+30

0

80

120

+35

0

25

+35

0

120

180

+40

0

31

+40

0

180

250

+46

0

38

+46

0

250

315

+52

0

44

+52

0

315

400

+57

0

50

+57

0

400

500

+63

0

56

+63

0

500

630

+70

0

 -

+70

0

630

800

+80

0

 -

+80

0

800

1000

+90

0

 -

+90

0

1000

1250

+105

0

 -

+105

0

1250

1600

+125

0

 -

+125

0

1600

2000

+150

0

 -

+150

0


Tolerance of Class 0 tapered bore of radial bearing (tapered bore = 1:30)

d

dmp

Vdp

d1mp-dmp

over

incl

high

low

max

high

low

mm

μm

μm

μm

80

120

+20

0

25

+40

0

120

180

+25

0

31

+50

0

180

250

+30

0

38

+55

0

250

315

+35

0

44

+60

0

315

400

+40

0

50

+65

0

400

500

+45

0

56

+75

0

500

630

+50

0

63

+85

0

630

800

+75

0

+100

0

800

1000

+100

0

+100

0

1000

1250

+125

0

+115

0

1250

1600

+160

0

+125

0

1600

2000

+200

0

+150

0

Clearance

SFT bearing radial clearance accords with the Chinese national standard GB/T 4604,
which is equal to ISO 5753

The clearances is classified into 5 groups, C2, C0, C3, C4, C5 with different applications
depending on customer's request

Radial clearance of deep groove ball bearing

d

C2

C0

C3

C4

C5

over

incl.

min.

max

min.

max

min.

max

min.

max

min.

max

mm

μm

2.5

6

1

8

5

15

10

20

15

25

21

33

6

10

2

9

6

17

12

25

19

33

27

42

10

14

2

10

6

19

13

26

21

35

30

48

14

18

3

12

8

21

15

28

23

37

32

50

18

24

4

14

10

23

17

30

25

39

34

52

24

30

5

16

11

24

19

35

29

46

40

58

30

40

6

18

13

29

23

40

34

53

46

66

40

50

6

19

14

31

25

44

37

57

50

71

50

65

7

21

16

36

30

50

45

69

62

88

65

80

8

24

18

40

35

60

54

83

76

108

80

100

9

27

22

48

42

70

64

96

89

124

100

120

10

31

25

56

50

83

75

114

105

145

120

140

10

38

30

68

60

100

90

135

125

175

140

160

15

44

35

80

70

120

110

161

150

210


Radial clearance of cylindrical bore self-aligning ball bearing

d

C2

C0

C3

C4

C5

over

incl

min

max

min

max

min

max

min

max

min

max

mm

μm

18

24

7

17

13

26

20

33

28

42

37

55

24

30

9

20

15

28

23

39

33

50

44

62

30

40

12

24

19

35

29

46

40

59

52

72

40

50

14

27

22

39

33

52

45

65

58

79

50

65

18

32

27

47

41

61

56

80

73

99

65

80

23

39

35

57

50

75

69

98

91

123

80

100

29

47

42

68

62

90

84

116

109

144

100

120

35

56

50

81

75

108

100

139

130

170

120

140

40

68

60

98

90

130

120

165

155

205

140

160

45

74

65

110

100

150

140

191

180

240


Radial clearance of tapered bore self-aligning ball bearing

d

C2

C0

C3

C4

C5

over

incl

min

max

min

max

min

max

min

max

min

max

mm

μm

 -

10

0

25

20

45

35

60

50

75

 -

 -

10

24

0

25

20

45

35

60

50

75

65

90

24

30

0

25

20

45

35

60

50

75

70

95

30

40

5

30

25

50

45

70

60

85

80

105

40

50

5

35

30

60

50

80

70

100

95

125

50

65

10

40

40

70

60

90

80

110

110

140

65

80

10

45

40

75

65

100

90

125

130

165

80

100

15

50

50

85

75

110

105

140

155

190

100

120

15

55

50

90

85

125

125

165

180

220

120

140

15

60

60

105

100

145

145

190

200

245

140

160

20

70

70

120

115

165

165

215

225

275

160

180

25

75

75

125

120

170

170

220

250

300

180

200

35

90

90

145

140

195

195

250

275

330

200

225

45

105

105

165

160

220

220

280

305

365

225

250

45

110

110

175

170

235

235

300

330

395

250

280

55

125

125

195

190

260

260

330

370

440

280

315

55

130

130

205

200

275

275

350

410

485

315

355

65

145

145

225

225

305

305

385

455

535

355

400

100

190

190

280

280

370

370

460

510

600

400

450

110

210

210

310

310

410

410

510

565

665

450

500

110

220

220

330

330

440

440

550

625

735


Radial clearance of tapered bore spherical roller bearing

d

C2

C0

C3

C4

C5

over

incl

min

max

min

max

min

max

min

max

min

max

mm

μm

14

18

10

20

20

35

35

45

45

60

60

75

18

24

10

20

20

35

35

45

45

60

60

75

24

30

15

25

25

40

40

55

55

75

75

95

30

40

15

30

30

45

45

60

60

80

80

100

40

50

20

35

35

55

55

75

75

100

100

125

50

65

20

40

40

65

65

90

90

120

120

150

65

80

30

50

50

80

80

110

110

145

145

180

80

100

35

60

60

100

100

135

135

180

180

225

100

120

40

75

75

120

120

160

160

210

210

260

120

140

50

95

95

145

145

190

190

240

240

300

140

160

60

110

110

170

170

220

220

280

280

350

160

180

65

120

120

180

180

240

240

310

310

390

180

200

70

130

130

200

200

260

260

340

340

430

200

225

80

140

140

220

220

290

290

380

380

470

225

250

90

150

150

240

240

320

320

420

420

520

250

280

100

170

170

260

260

350

350

460

460

570

280

315

110

190

190

280

280

370

370

500

500

630

315

355

120

200

200

310

310

410

410

550

550

690

355

400

130

220

220

340

340

450

450

600

600

750

400

450

140

240

240

370

370

500

500

660

660

820

450

500

140

260

260

410

410

550

550

720

720

900

500

560

150

280

280

440

440

600

600

780

780

1000

560

630

170

310

310

480

480

650

650

850

850

1100

630

710

190

350

350

530

530

700

700

920

920

1190

710

800

210

390

390

580

580

770

770

1010

1010

1300

800

900

230

430

430

650

650

860

860

1120

1120

1440

900

1000

260

480

480

710

710

930

930

1220

1220

1570

Vibration & Noise

Bearing vibration means bearing components' elastic deformation that varies with time and all other
movement that deviates from a theoretic position except that necessary to bearing functions.
It has two modes-acceleration (dB) and velocity (um/s).
Vibration acceleration is examined according to Z, Z1, Z2, Z3 values. Grade Z is fundamental.
Z1, Z2, Z3 successively indicate the vibration level ranging from low to high.  
Vibration velocity is examined as per V, V1, V2 and V3. Grade V is fundamental,
V1, V2, V3 successively indicate the vibration level ranging from low to high.

Vibration acceleration limits for single deep groove ball bearing

d

Diameter series (0)

Diameter series (2)

Diameter series (3)

mm

Z

Z1

Z2

Z3

Z

Z1

Z2

Z3

Z

Z1

Z2

Z3

3

35

34

32

28

36

35

32

30

37

36

33

31

4

35

34

32

28

36

35

32

30

37

36

33

31

5

37

36

34

30

38

37

34

32

39

37

35

33

6

37

36

34

30

38

37

34

32

39

37

35

33

7

39

38

35

31

40

38

36

34

 -

 -

 -

 -

8

39

38

35

31

40

38

36

34

 -

 -

 -

 -

9

41

40

36

32

42

40

37

35

 -

 -

 -

 -

10

43

42

38

33

44

42

39

35

46

44

40

37

12

44

43

39

34

45

43

39

35

47

45

40

37

15

45

44

40

35

46

44

41

36

48

46

42

38

17

46

44

40

35

47

45

41

36

49

47

42

38

20

47

45

41

36

48

46

42

38

50

48

43

39

22

47

45

41

36

48

46

42

38

50

48

43

39

25

48

46

42

38

49

47

43

40

51

49

44

41

28

49

47

43

39

50

48

44

41

52

50

45

42

30

49

47

43

39

50

48

44

41

52

50

45

42

32

50

48

44

40

51

49

45

42

53

51

46

43

35

51

49

45

41

52

50

46

43

54

52

47

44

40

53

51

46

42

54

52

47

44

56

54

49

45

45

55

53

48

45

56

54

49

46

58

56

51

47

50

57

54

50

47

58

55

51

48

60

57

53

49

55

59

56

52

49

60

57

53

50

62

59

54

51

60

61

58

54

51

62

59

54

51

64

61

56

53

65

49

48

46

 -

50

49

47

42

51

50

48

43

70

50

49

47

 -

51

50

48

43

52

51

49

44

75

51

50

48

 -

52

51

49

44

53

52

50

45

80

52

51

49

 -

53

52

50

45

54

53

51

46

85

53

52

50

 -

54

53

51

46

56

55

52

47

90

54

53

52

 -

56

55

53

48

58

57

54

49

95

56

55

54

 -

58

57

55

50

60

59

56

51

100

58

57

56

 -

60

59

57

52

62

61

58

53

105

60

59

58

 -

62

61

59

54

64

63

60

55

110

62

61

60

 -

64

63

61

56

66

65

62

57

120

64

63

62

 -

66

65

63

58

68

67

64

59


Vibration velocity limits for single deep groove ball bearing

d

V

V1

V2

V3

mm

low

medium

high

low

medium

high

low

medium

high

low

medium

high

band

band

band

band

band

band

band

band

band

band

band

band

3

80

44

44

60

35

32

48

26

22

31

16

15

4

80

44

44

60

35

32

48

26

22

31

16

15

5

110

72

60

74

48

40

58

36

30

35

21

18

6

110

72

60

74

48

40

58

36

30

35

21

18

7

130

96

80

92

66

54

72

48

40

44

28

24

8

130

96

80

92

66

54

72

48

40

44

28

24

9

130

96

80

92

66

54

72

48

40

44

28

24

10

160

120

100

120

80

70

90

60

50

55

35

30

12

160

120

100

120

80

70

90

60

50

55

35

30

15

210

150

120

150

100

85

110

78

60

65

46

35

17

210

150

120

150

100

85

110

78

60

65

46

35

20

260

190

150

180

125

100

130

100

75

80

60

45

22

260

190

150

180

125

100

130

100

75

80

60

45

25

260

190

150

180

125

100

130

100

75

80

60

45

28

260

190

150

180

125

100

130

100

75

80

60

45

30

300

240

190

200

150

130

150

120

100

90

75

60

32

300

240

190

200

150

130

150

120

100

90

75

60

35

300

240

190

200

150

130

150

120

100

90

75

60

40

360

300

260

240

180

160

180

150

130

110

90

80

45

360

300

260

240

180

160

180

150

130

110

90

80

50

420

320

320

280

200

200

210

160

160

125

100

100

55

420

360

360

280

220

200

210

180

180

125

110

110

60

480

360

440

320

220

240

240

180

200

145

110

130

65

300

260

420

180

160

240

130

100

150

105

80

105

70

360

310

460

200

180

280

150

120

200

110

90

135

75

360

310

460

200

180

280

150

120

200

110

90

135

80

420

360

540

240

210

320

180

120

240

130

110

160

85

420

360

540

240

210

320

180

150

240

130

110

160

90

480

420

600

290

250

370

210

180

270

145

125

180

95

480

420

600

290

250

370

210

180

270

145

125

180

100

560

490

670

340

300

420

250

215

310

170

145

200

105

560

490

670

340

300

420

250

215

310

170

145

200

110

640

570

750

400

350

480

290

260

350

190

175

225

120

640

570

750

400

350

480

290

260

350

190

175

225

COPYRIGHT 2012 SHAANXI FORTUNE TRADE CO.,LTD. ALL RIGHT RESERVED.Shaan ICP Preparation NO.12001542
Address: A-1007 10 FENG CHENG III ROAD XI'AN CHINA Tel:86-29-86528771