ISO 7412

Scope

This International Standard gives specifications for large series hexagon, high -strength structural bolts with metric dimensions in property classess 8.8 and 10.9, and thread sizes from M12 up to and including M36, with short thread lengths.

Dimensions

Shape And Dimensions Of Stud

General Dimensions1)

Dimensions in millimetres

Thread size d M122) M16 M20 (M22)3) M24 (M27)3) M30 M36
   P4) 1.75 2 2.5 2.5 3 3 3,5 4
bref 5) 25 31 36 38 41 44 49 56
6) 32 38 43 45 48 51 56 63
c max. 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8
min. 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4
da max. 14.7 18.7 23.24 25.24 27.64 31.24 34.24 41.00
ds max. 12.70 16.70 20.84 22.84 24.84 27.84 30.84 37.84
min. 11.30 15.30 19.16 21.16 21.16 26.16 29.16 35.00
dw max. 7) 7) 7) 7) 7) 7) 7) 7)
min. 19.2 24.9 31.4 33.3 38.0 42.8 46.5 55.9
e min. 22.78 29.56 37.29 39.55 45.20 50.85 55.37 66.44
k nom. 7.5 10 12.5 14 15 17 18.7 22.5
max. 7.95 10.75 13.40 14.90 15.90 17.90 19.75 23.55
min. 7.05 9.25 11.60 13.10 14.10 16.10 17.65 21.45
k' min. 4.9 6.5 8.1 9.2 9.9 11.3 12.4 15.0
r min. 0.6 0.6 0.8 0.8 1.0 1.2 1.2 1.5
s max. 21 27 34 36 41 46 50 60
min. 20.16 26.16 33 35 40 45 49 58.8
l ls and lg8)
nom. min. max. ls
min.		 lg
max.		 ls
min.		 lg
max.		 ls
min.		 lg
max.		 ls
min.		 lg
max.		 ls
min.		 lg
max.		 ls
min.		 lg
max.		 ls
min.		 lg
max.		 ls
min.		 lg
max.
30 28.95 31.05
35 33.75 36.25
40 38.75 41.25 9.8 15
45 43.75 46.25 14.8 20 8 14
50 48.75 51.25 19.8 25 13 19
55 53.5 56.5 24.8 30 18 24 11.5 19
60 58.5 61.5 29.8 35 23 29 16.5 24 14.5 22
65 63.5 66.5 34.8 40 28 34 21.5 29 19.5 27 15 24
70 68.5 71.5 39.8 45 33 39 26.5 34 24.5 32 20 29 17 26
75 73.5 76.5 44.8 50 38 44 31.5 39 29.5 37 25 34 22 31
80 78.5 81.5 49.8 55 43 49 36.5 44 34.5 42 30 39 27 36 20.5 31
85 83.25 86.75 54.8 60 48 54 41.5 49 39.5 47 35 44 32 41 25.5 36
90 88.25 91.75 59.8 65 53 59 46.5 54 44.5 52 40 49 37 46 30.5 41 22 34
95 93.25 96.75 64.8 70 58 64 51.5 59 49.5 57 45 54 42 51 35.5 46 27 39
100 98.25 101.75 69.8 75 63 69 56.5 64 54.5 62 50 59 47 56 40.5 51 32 44
110 108.25 111.75 66 72 59.5 67 57.5 65 53 62 50 59 43.5 54 35 47
120 118.25 121.75 76 82 69.5 77 67.5 75 63 72 60 69 53.5 64 45 57
130 128 132 86 92 79.5 87 77.5 85 73 82 70 79 63.5 74 55 67
140 138 142 96 102 89.5 97 87.5 95 83 92 80 89 73.5 84 65 77
150 148 152 106 112 99.5 107 97.5 105 93 102 90 99 83.5 94 75 87
160 156 164 103 112 100 109 93.5 104 85 97
170 166 174 113 122 110 119 103.5 114 95 107
180 176 184 123 132 120 129 113.5 124 105 117
190 186 194 133 142 130 139 123.5 134 115 127
200 196 204 143 152 140 149 133.5 144 125 137

1) For hot-dip galvanized bolts, the above dimensions apply before galvanizing.
2) None-preferred for technical reasons.
3) Indicates second choice diameter.
4) P = pitch of thread
5) For lengths lnom < 100 mm.
6) For lengths Inom > 100 mm.
7) dwmax = s actual
8) lg max = lnom - b ref
     ls min = lg max - 3 P
NOte -- The popular lenghts are shown between heavy lines.

Specifications And Reference Standards

Material Steel
  Thread Tolerance 6 g1)
International Standard ISO 261, ISO 965
  Mechanical Properties Class 8.8 10.9
International Standard ISO 989/1
  Surface Finish Normal Black Oxidie 2)
optional3) Zinc electroplated 4) Zinc electroplated 5)
Cadmium electroplated 4) Cadmium electroplated 5)
Hot-dip galvanized to ISO 1461 Hot-dip galvanized to ISO 1461 6)
Product grade C except:
c,dw min (0.95 smin) and r
Tolerance for lenghts over 180 mm: ± 4.0 mm
  Tolerance International Standard ISO 4759/1
  Acceptability For Acceptance procedure, see ISO 3269.
  Assocaited nuts ISO 4775 or ISO 7414
  Assocaited plain hote washers ISO 7415
  Assocaited Chamfered hole washers ISO 7416

1) The tolerance class specified applies before electroplating or hot-dip galvanizing. Hot-dip galvanized bolts may also be supplied by agreement between the user and the manufacturer, having screw threads which after galvanizing shall be accepted by a GO gauge of the basic thread size, ¡.e. the bolt threads are undersized before galvanizing to tolerance class 6az to accommodate the zinc coating. These bolts are designated and marked 8.8s U or 10.9s U (see also clauses 6 and 7). Tolerance class 6az is in the course of preparation, but in the interim the screw thread dimensions are given in annex A.
2) Black oxide means the normal finish resulting from manufacture with a light coating of oil.
3) Other coatings may be negotiated between the purchaser and the manufacturer provided they do not impair the mechanical properties.
4) This will be the subject of a future International Standard.
5) Precautions to avoid hydrogen embrittlement may be necessary. Reference should be made to the future International Standard dealing with electroplating of threaded components.
6) Precautions to avoid hydrogen embrittlement may be necessary.