The following is a recommended maximum torque table for bolt tensioners to help the operator determine the torque of hydraulic bolt tensioners to select the right bolt tensioners.

The datas are mainly suitable for bolt tensioner and hydraulic nut.

Strength grade4.86.88.810.912.9
Min breaking strength400MPa600MPa800MPa1000MPa1200MPa
MaterialGeneral structural
steel		Mechanical
construction steel		Chrome
molybdenum
alloy steel		Ni-Cr-Mo alloy steelNi-Cr-Mo alloy steel
BoltA/FTightening Force
MS(KN)
162430456085102
1827375574104125
2030477194132159
22345887117164197
243668102135190228
274188132176248298
3046108161215303363
3350133200266375449
3655157235314441529
3960187281375527632
4265215323430605726
4570251376502705846
4875283424566796955
52803385066759491139
568539058578010961315
609045468090712751531
6495514771102814451734
68100587880117316501980
72105664996132918682242
761107471120149421002520
801158341251166823462815
851209501425190026723206
9013010731610214730193623
10014513432014268637774533
11015516432464328546205544
12017519732959394555486657
12518021493223429860437252

Attention:
The data in the chart is measured under 60% yield limit of the bolt, the recommended tightening torque is
70-80% of above data.
For example, for M42 grade 10.8 bolt, the tightening torque is 605*(70-80)% = 423.5-484KN.