Standard parts use basic knowledge

Product Usage Note: Stainless steel and carbon steel have essential differences. Stainless steel has good ductility. Improper use can cause screws and nuts to fit together and cannot be unscrewed. This is commonly known as "locking" or "killing." To improve the locking can be mainly considered from the following aspects:

1. Correct choice of product:
(1) Before use, confirm whether the mechanical properties of the product can meet the requirements for use (such as the tensile strength of the bolt and the safety load of the nut);
(2) The length of the bolt should be properly selected to tighten the screw and reveal the 1-2 pitch of the nut.

2. Reduce friction coefficient:
(1) Threads must be kept clean;
(2) Add lubricant (such as: 40# oil, butter) properly before use.

3. The correct method of operation:
(1) The nut must be screwed perpendicular to the axis of the screw and must not be tilted;
(2) During the tightening process, the force must be uniform, and the force cannot exceed the value of the safe torsion (with a safe torsional moment table);
(3) Use torque wrenches or socket wrenches as much as possible to avoid the use of adjustable wrenches or electric wrenches;
(4) When used in high temperature conditions, it must be cooled, and do not rotate quickly during use, so as to avoid sudden temperature rises (such as electric wrenches, etc.).

4. Safe torque torque reference table:
(1) Use equipment: torque wrench, bench vise, matching sleeve:
(2) Screw and nut performance grade; A2-70, 304 material, tensile strength: 700N/mm2, dropout strength: 450 N/mm2;
(3) Working mode: Vertically clamp the screw head on the bench vise, sandwich a workpiece, a flat pad and a spring washer, and then apply the nut to evenly apply force as the following force on the nut reaches below: At the value, the nut can no longer be screwed out smoothly.
(4) Safe torque torque meter: Unit: Nm Specifications M20-2.5 M18-2.5 M16-2.0 M14-2.0 M12-1.75 Safe torque 220 180 150 100 55 Specifications M10-1.5 M8-1.25 M6-1.0 Safe torque 40 40 9 Note : The above data was obtained for the above experimental conditions and is for reference only. The actual data is affected by the construction conditions, but the maximum should not exceed this moment.