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Sub-clause number
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Mechanical and physical property
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Property Class
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3.6
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4.6
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4.8
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5.6
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5.8
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6.8
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8.8a
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9.8b
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10.9
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12.9
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||||
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d ≤ 16c mm
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d ＞ 16c mm
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5.1
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Nominal tensile strength, Rm.nom N/mm2
|
300
|
400
|
500
|
600
|
800
|
800
|
900
|
1000
|
1200
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|||
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5.2
|
Minimum tensile strength. Rm,min de N/mm2
|
330
|
400
|
420
|
500
|
520
|
600
|
800
|
830
|
900
|
1040
|
1220
|
|
|
5.3
|
Vickers hardness, HV
F ≥ 98 N |
min.
|
95
|
120
|
130
|
155
|
160
|
190
|
250
|
255
|
290
|
320
|
385
|
|
max.
|
220f
|
250
|
320
|
335
|
360
|
380
|
435
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5.4
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Brinell hardness,
HB F = 30 D2 |
min.
|
90
|
114
|
124
|
147
|
152
|
181
|
238
|
242
|
276
|
304
|
366
|
|
max.
|
209f
|
238
|
304
|
318
|
342
|
361
|
414
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5.5
|
Rockwell hardness. HR
|
min. HRB
|
52
|
67
|
71
|
79
|
82
|
89
|
/
|
/
|
/
|
/
|
/
|
|
min. HRC
|
/
|
/
|
/
|
/
|
/
|
/
|
22
|
23
|
28
|
32
|
39
|
||
|
max.HHB
|
95.0f
|
99.5
|
/
|
/
|
/
|
/
|
/
|
||||||
|
max.HRC
|
/
|
32
|
34
|
37
|
39
|
44
|
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5.6
|
Surface hardness, HV 0.3
|
max.
|
/
|
9
|
|||||||||
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5.7
|
Lower yield stress R eL h. N/mm2
|
nom.
|
180
|
240
|
320
|
300
|
400
|
480
|
/
|
/
|
/
|
/
|
/
|
|
min.
|
190
|
240
|
340
|
300
|
420
|
480
|
/
|
/
|
/
|
/
|
/
|
||
|
5.8
|
Stress at 0.2 % non-proportional elongation Rp0.2i . N/mm2
|
nom.
|
/
|
/
|
640
|
640
|
720
|
900
|
1080
|
||||
|
min.
|
/
|
/
|
640
|
660
|
720
|
940
|
1100
|
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5.9
|
Stress under proof load. Sp
|
Sp/ReL or Sp/Rp 0.2
|
0.94
|
0.94
|
0.91
|
0.93
|
0.90
|
0.92
|
0.91
|
0.91
|
0.90
|
0.88
|
0.88
|
|
N/mm2
|
180
|
225
|
310
|
280
|
380
|
440
|
580
|
600
|
650
|
830
|
970
|
||
|
5.10
|
Breaking torque. MB Nm min
|
/
|
See iSO 898-7
|
||||||||||
|
5.11
|
Percent elongation after fracture. A min.
|
25
|
22
|
/
|
20
|
/
|
/
|
12
|
12
|
10
|
9
|
8
|
|
|
5.12
|
Reduction area after fracture. Z % min.
|
/
|
52
|
48
|
48
|
44
|
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5.13
|
Strength under wedge loading a
|
The values for full size bolts and screws (no studs) shall not be smaller than the minimum values for tensile strength shown in 5.2
|
|||||||||||
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5.14
|
Impact strength.KU J min.
|
/
|
25
|
/
|
30
|
30
|
25
|
20
|
15
|
||||
|
5.15
|
Head soundness
|
No fracture
|
|||||||||||
|
5.16
|
Minimum height of non-decarburized
thread zone, £ |
/
|
1/2 H1
|
2/3 H1
|
3/4 H1
|
||||||||
|
Maximum depth of complete mm
decarburization, G |
/
|
0.015
|
|||||||||||
|
5.17
|
Hardness after retempering
|
/
|
Reduction of hardness 20 HV maximum
|
||||||||||
|
5.18
|
Surface integrity
|
In accordance with ISO 6157-1 or ISO 6157-3 as appropriate
|
|||||||||||
a.For bolts of property class 8.8 in diameters ≤ 16 mm, there is an increased risk of nut stripping in the case of inadvertent over-tightening inducing a load in excess of proof load. Reference to ISO 898-2 is recommended.
b.Applies only to nominal thread diameters d ≤ 16 mm.
c.For structural bolting the limit is 12 mm.
d.Minimum tensile properties apply to products of nominal length l< 2,5 d.Minimum hardness applies to products of length l < 2,5 d and other products which cannot be tensile-tested (e.g. due to head configuration).
e.When testing full-size bolts, screws and studs, the tensile loads, which are to be applied for the calculation of Rm, shall meet the values given in tables 6 and 8.
f. A hardness reading taken at the end of bolts, screws and studs shall be 250 HV, 238 HB or 99,5 HRB maximum.
g.Surface hardness shall not be more than 30 Vickers points above the measured core hardness on the product when readings of both surface and core are carried out at HV 0,3. For property class 10.9, any increase in hardness at the surface which indicates that the surface hardness exceeds 390 HV is not acceptable.
h.In cases where the lower yield stress ReL cannot be determined, it is permissible to measure the stress at 0.2% non-proportional elongation For the properly classes 4.8, 5.8 and 6.8 the values for ReL are given for calculation purposes only, they are not test values.
i. The yield stress ratio according to the designation of the property class and me minimum stress at 0.2 % non-proportional elongation Rp0.2 apply to machined test specimens.
These values if received from tests of full size bolts and screws will vary because of processing method and size effects