Do I need lubricant between flange and bolt?

You need to apply lubricant between the flange and the bolt. The following is a detailed explanation of this practice:

First, the role of applying lubricant

Reduce friction: Bolt lubrication can effectively reduce the loss of friction to the preload force, so that the bolt can more easily reach the predetermined tightening force during the tightening process.

Prevent direct metal contact: After applying lubricant, a lubricating film can be formed between the flange and the bolt to prevent direct contact between the metal and the metal, thereby avoiding wear, cold welding, sticking or sintering problems.

Improve sealing: The lubricant can also play a good sealing role to prevent the corrosion of moisture, dust and other media, which is conducive to the maintenance of system pressure.

Second, the specific steps of applying lubricant

Cleaning and rust removal: Before applying lubricant, it is necessary to clean the threaded part of the flange and bolt to remove burrs, rust, dust and dirt, etc., to ensure that the lubricant can be evenly applied on the surface of the thread.

Select the right lubricant: Select the right lubricant according to the material, working environment and torque requirements of the bolt. There are many kinds of lubricants, such as oil, butter, silicone oil, synthetic lubricants, etc., which should be selected according to the specific application.

Apply lubricant: Apply appropriate amount of lubricant to the contact surface of the bolt and flange, as well as the threaded part of the bolt and nut. When applying, ensure that the lubricant is evenly distributed, not too much or too little. Too much lubricant may lead to lubricant loss or contamination of surrounding parts, while too little lubricant will not achieve the effect of reducing friction.

Assembly and inspection: After applying lubricant, the bolts and flanges should be temporarily assembled so that the lubricant is fully distributed between the threads. After the assembly is completed, check whether the distribution of the lubricant and the fastening force meet the requirements.

Third, precautions

Avoid the use of inappropriate lubricants: When selecting lubricants, ensure that they are compatible with the material of the flange and bolt and meet the requirements of the working environment. Avoid lubricants that may cause chemical reactions or corrosion.

Regular inspection and replacement of lubricants: During use, the lubrication of bolts and flanges should be checked regularly. If the lubricant is found to be lost, deteriorated or contaminated, the lubricant should be replenished or replaced in time.

Follow the safe operating procedures: When applying lubricants, you should follow the relevant safe operating procedures to avoid accidents. If you need to use equipment such as power tools or high-pressure water guns, ensure the safety and stability of the equipment.

To sum up, it is very necessary to apply lubricant between the flange and the bolt. The correct application method and suitable lubricant selection can significantly improve the tightness and reliability of flange connections and extend the service life of piping systems.