Metric Bolt Specifications
Bolt Marking
Bolt Type
Tensile Strength
n/sq mm
n/sq mm
Shear Strength
n/sq mm
n/sq mm
4.6
Low or Medium Carbon Steel
400
4.8
Low or Medium Carbon Steel
Fully or Partially Annealed
Fully or Partially Annealed
420
5.8
Low or Medium Carbon Steel
Cold Worked
Cold Worked
520
8.8
Medium Carbon Steel
Quenched & Tempered
Quenched & Tempered
800
10.9
Alloy Steel
Quenched & Tempered
Quenched & Tempered
1040
12.9
Alloy Steel
Quenched & Tempered
Quenched & Tempered
1220
None
Stainless Steel Class 50
500
A2-70
Stainless Steel 302
700
311 n/sq mm
A4-80
Stainless Steel 316
800
384 n/sq mm
A4-80
Stainless Steel Bumax88
800
384 n/sq mm
?
Stainless Steel Class 100
1000
Notes
Stainless bolt markings
Ax = grade, A2 normally 304, A4 normally 316
-xx = temper, 70 = cold worked, 80 = machined from strain hardened stock
-xx = temper, 70 = cold worked, 80 = machined from strain hardened stock
Shear Strength
Shear strength of fasteners is in part dependant on the thread pitch
In general terms it can be calculated, shear strength = 0.6* UTS
where UTS = Ultimate Tensile Strength
In general terms it can be calculated, shear strength = 0.6* UTS
where UTS = Ultimate Tensile Strength
Generic Bolt Torque Values to pin on the workshop wall
A simple torque unit converter to pin on the workshop wall