Mechanical Properties  - Nuts & Bolts

Sub-Clause
Number
Mechanical & Physical Property 3.6 4.6 4.8 5.6 5.8 6.6 8.6 9.8b 10.9 12.9
d<16c
mm
d>16c
mm
5.1 Nominal tensile strength   N/mm2 300

400

500 600 800 800 900 1000 1200
5.2 Minimum tensile strength  N/mm2 330 400 420 500 520 600 800 830 900 1040 1220
5.3

Vickers Hardness HV
f.96 N

Min 95 120 130 155 160 190 250 255 290 320 385
Max 220f 250 320 335 360 380 435
5.4

Bridenell hardness HB
F = 30D2

Min 90 114 124 147 152 181 238 242 276 304 366
Max 209 238 304 318 342 361 414
5.5 Rockwell Hardness HV 0,3 Min HRB 52 67 71 79 82 89 - - - - -
HRC - - - - - - 22 23 28 32 39
Max HRB 95.0 99.5 - - - - -
HRC

-

  32 34 37 39 44
5.6

Surface Hardness HV 0,3       Max

-

9

5.7

Lower Yield Stress 
Rd 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 Rpo,21 N/mm2

Nom - 640 640 720 900 1080
Min - 640 660 720 940 1100
5.9 stress under proof load sp

N/mm2

0.94 0.94 0.91 0.93 0.90 0.92 0.91 0.91 0.90 0.88 0.88
180 225 310 280 380 440 580 600 650 830 970
5.10 Breaking Torque

N/mm2

- see ISO 896-7
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
5.13 Strength under wedge loading

The values for full size bolts & screws (no studs) shall not be smaller than the minimum values for tensile strength shown in 5.2

5.14 Impact strength        25      30 30  25  20  15 
 5.15 Head Soundness                       
 5.16

 

 Minimum height of non decarburized 
thread zone. E

              H1        H1
         Maximum depth of complete               mm
                  decarburization, G
                 0,015    
 5.17  Hardness after retempering                      
 5.18  Surface Integrity