Basic use of standard parts common sense

Release time:

2023-02-06

Stainless steel and carbon steel have essential differences, stainless steel has good ductility, improper use of screws and nuts can not be unscrewed. This is commonly known as "lock" or "bite". The improvement of locking can be mainly considered from the following aspects

Precautions for product use: stainless steel and carbon steel have essential differences, stainless steel has good ductility, improper use will lead to screw and nut can not be unscrewed. This is commonly known as "lock" or "bite". The improvement of locking can be mainly considered from the following aspects:
1. Choose the right product:
(1) Before use, confirm whether the mechanical properties of the product can meet the requirements of use (such as the tensile strength of the bolt and the safety load of the nut);
(2) The length of the bolt should be selected appropriately, with 1-2 pitch of the exposed nut after tightening.
2. Reduce the coefficient of friction:
(1) The threads must be kept clean;
(2) Add lubricant (such as 40# oil, butter) before use.
3. The correct method of operation:
(1) The nut must be perpendicular to the axis of the screw for screwing, do not tilt;
(2) In the process of tightening, the force must be uniform, and the force must not exceed the safety torque value (with safety torque table);
(3) Use torque wrench or socket wrench as much as possible, and avoid using adjustable wrench or electric wrench;
(4) It must be cooled when used at high temperature, and do not rotate quickly during use, so as to avoid the rapid rise in temperature and cause locking (such as electric wrenches, etc.).

4. Safety torque reference table:
(1) Use equipment: torque wrench, bench vise, matching sleeve:
(2) Performance grade of screws and nuts; A2-70 and 304 materials, tensile strength: 700N/mm², reducing strength: 450 N/mm²;
(3) Operation mode: clamp the screw head vertically on the bench vise, clamp a workpiece, a flat pad and a spring pad in the middle, and then apply the nut evenly. When the force applied to the nut reaches the following value, the nut cannot be unscrewed smoothly.
(4) Safety Torque Table: Unit: N.m Specification M20-2.5 M18-2.5 M16-2.0 M14-2.0 M12-1.75 Safety Torque 220 180 150 100 55 Specification M10-1.5 M8-1.25 M6-1.0 Safety Torque 40 409 Note: The above data are obtained for the above experimental conditions and are for reference only. The actual data is affected by the construction conditions, but the maximum should not exceed this moment.