Recommended Assembly Torques Stainless Steel and Class 4.6

Recommended Assembly Torques
Class 4.6 ISO Metric Coarse Pitch Bolts and Screws
 
Diameter Pitch (mm) Bolt Tension Corresponding to 65% of Proof Load kN Recommended Assembly Torque
Nm
M1.6 0.35 0.19 0.06
M2 0.40 0.31 0.12
M2.5 0.45 0.50 0.25
M3 0.50 0.73 0.44
M4 0.70 1.29 1.0
M5 0.80 2.08 2.1
M6 1.00 2.94 3.5
M8 1.25 5.34 8.5
M10 1.50 8.45 17
M12 1.75 12.4 30
M14 2.00 16.8 47
M16 2.00 22.9 73
M18 2.50 28.1 101
M20 2.50 35.8 143
M22 2.50 44.3 195
M24 3.00 51.6 248
M27 3.00 67 362
M30 3.50 81.9 491
M33 3.50 101 669
M36 4.00 120 864
M39 4.00 143 1115
M42 4.50 164 1378
M48 5.00 215 2064
M56 5.50 298 3338
M64 6.00 393 5030
 
To convert kN to Ibft - Multiply kN by 224.809
To convert Nm to Ibft - Multiply Nm by 0.737562

 Table 2
Surface Condition Torque Adjustment Factors
Plain steel, as supplied x 1.0
Plain steel, degreased x 2.0
Zinc Plated, as supplied x 1.0
Zinc Plated, lightly oiled x 0.9
Galvanized, degreased x 2.1
Galvanized, lightly oiled x 1.1
Heavily greased x 0.7


In the absence of site specific torque values or engineering calculations, the charts above can be used as a guide to the maximum safe torque for a particular size/grade fastener. There is no torque difference for fine or coarse threads.
NB: Refer Table 2  for finish and lubricant coatings when calculating values.
 
 
Recommended Assembly Torques
Stainless Steel Class 70                                                                            
ISO Metric Coarse Pitch Bolts and Screws

 
Diameter Pitch (mm) Recommended Assembly Torque
Nm
M3 0.50 0.90
M4 0.70 2
M5 0.80 4.10
M6 1.00 7
M8 1.25 17
M10 1.50 33
M12 1.75 57
M14 2.00 91
M16 2.00 140
M20 2.50 273
M24 3.00 472
M27 3.00 682
M30 3.50 930
M36 4.00 1620
 
To convert kN to Ibft - Multiply kN by 224.809
To convert Nm to Ibft - Multiply Nm by 0.737562
 
 
In the absence of site specific torque values or engineering calculations, the chart above can be used as a guide to the maximum safe torque for a particular size/grade fastener.
 
 
  • Information refers to flat burr-free surfaces lubricated with good quality lubricant such as MOLYBOND®
  • The nominal induced load in joints tightened to these torque values is calculated as 65% of the load at the permanent set limit but in practice, the value can be expected to vary between 50% and 80% of the load at the permanent set limit.
  • Calculations assume a coefficient friction of 0.16, which requires good quality lubricant such as MOLYBOND®
  • Even slight variations from normal test conditions can produce wide variations in friction. Accordingly when friction coefficients are used in design calculations due allowance or factors of safety should be considered and in critical cases, specific tests conducted to provide actual coefficients for material, geometry, site conditions and/or lubricant combinations.
PDF file for print Stainless Steel

PDF file for print Class 4.6