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This standard replaces JB/T 6040-1992 Construction machinery - Test methods of tightening torque for bolts.
The following main changes have been made with respect to JB/T 6040-1992:
——The English name of the standard has been added on the front cover;
——Some editorial adjustments have been made to the whole standard.
——Annex A "Tightening torque values for bolts” has been added.
Annex A to this standard is informative.
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of SAC/TC 334 National Technical Committee on Earth-moving Machine of Standardization Administration of China.
The previous edition of this standard is as follows:
——JB/T 6040-1992.
Construction machinery - Test methods of tightening torque for bolts
1 Scope
This standard specifies test tools and methods of tightening torque for construction machinery bolts. The tightening torque values for bolts are shown in Annex A.
This standard is applicable to testing the tightening torque for construction machinery bolts.
2 Test tools
Torque wrench, adjustable wrench, needle or pen.
3 Test methods
3.1.1 General requirements
This standard specifies two test methods: direct test and accurate test. Direct test is recommended.
3.1.2 Direct test
For a tightened bolt, apply force slowly and evenly to the bolt head (or nut) along the tightening direction with a torque wrench; if necessary, clamp the nut (or bolt head) connected with the bolt with an adjustable wrench to prevent it from rotating. When the torque wrench makes a sound, record its value, which is the tightening torque of the bolt (in N·m).
3.1.3 Accurate test
For a tightened bolt, make a mark on the contact surface between the bolt head (or nut) and the bolt with a needle or pen, and then loosen the bolt head (or nut); if necessary, clamp the nut (or bolt head) connected with the bolt with an adjustable wrench to prevent it from rotating. Then apply force slowly and evenly along the tightening direction with a torque wrench until the nut (or bolt head) coincides with the mark, and record the value indicated on the torque wrench, which is the tightening torque of the bolt (in N·m).
Foreword I
1 Scope
2 Test tools
3 Test methods
Annex A (Informative) Tightening torque values for bolts
Table A.1 Tightening torque values for bolts
