High-strength Bolt Process Standard

1 Materials and main equipment:

1.1 The bolts, nuts and washers shall be attached with quality certificates and shall comply with the design requirements and national standards.

1.2 The storage of high-strength bolts should be classified and stored according to specifications, and protected from rain and moisture. If the bolt and nut are not matched, and the thread is damaged, it shall not be used. The bolts, nuts and washers are corroded, and the tightening axial force should be inspected by sampling to meet the requirements before use.

The bolts, etc. shall not be contaminated by dirt or oil, and shall be kept clean and dry. Must be used according to the batch number and matched in the same batch, and cannot be mixed and mixed.

1.3 Main tools: electric torque wrench and controller, manual torque wrench, manual wrench, wire brush, tool bag, etc.

2 Operating conditions:

2.1 Friction surface treatment: The friction surface is treated by sandblasting, grinding wheel and other methods, and the friction coefficient should meet the design requirements (one requirement is Q235 steel above 0.45, 16 manganese steel above 0.55) The friction surface wood is allowed to have residual iron scale. The treated friction surface can generate a red rust surface and then install the bolt (generally stored in the open air for about 10d). The friction surface treated by sandblasting can be installed without rust. When grinding with a grinding wheel, the grinding range is not less than 4 times the diameter of the bolt. The grinding direction is perpendicular to the direction of the force. The friction surface after grinding should have no obvious unevenness. The friction surface should be prevented from being contaminated by oil or paint.

2.2 Check the size of the hole diameter of the bolt hole. Any burrs on the edge of the hole must be removed.

2.3 Bolts, nuts and washers of the same batch number and specification shall be matched and packed in boxes for use.

2.4 Electric wrenches and manual wrenches should be calibrated.