What details should be paid attention to when maintaining special screws that have problems

In order to ensure the normal operation of the equipment, regular maintenance of special screws, which are insignificant small components of the equipment, is very necessary. Given the importance of special screws, it is important to pay attention to that aspect during maintenance in order to prevent problems with special screws.

Special screws

1、 Remove debris

Special screws need to be cleaned with silicate after quenching, and after cleaning, they also need to be washed with water. So to prevent residues and debris from appearing, it is important to be very careful when washing.

2. Special screws stacked and damaged

We sometimes encounter situations where special screws change color after being heated, and after soaking in ether, oily residue is found, indicating that the surface of the special screw is not clean. After analysis, it was found that this was due to improper stacking of special screws during heating, resulting in slight oxidation in the quenching oil.

3. Surface residues

Failure to clean high-strength screws with an acid cleaning machine and insufficient inspection of the rinsing tank can result in white residue on the screws, which was found to be phosphide after the first phase inspection.

4. Alkali burn

If a special steel screw enters the quenching oil without removing the surface alkaline substances, it will be found that the screw will turn black due to quenching waste heat and have a uniform and flat oil black outer surface. Because the screws that were not cleaned were burned on the surface at high temperatures, and the damage worsened during tempering. So before heat treatment, it is necessary to thoroughly clean the alkaline residue that may cause burns on special screws.

5. Improper rinsing

Sometimes it is found that when using polymer aqueous solution for quenching large-sized special screws, while using an alkaline cleaning machine for rinsing, the special screws have already rusted during internal testing. So to ensure that special screws do not rust during rinsing, it is necessary to frequently change the rinsing water.

6. Excessive corrosion

The excessive aging of quenching oil will leave some black stripes when high-strength special screws are dried, which is the residue of surface residue, which is the evolution of the gas phase during the quenching process. So it is recommended to add new oil.