Six points to pay attention to when maintaining rivets

1. Pollution caused by rinsing

Rivets need to be cleaned after quenching with a silicate cleaner and then rinsed, so be very careful when rinsing to prevent residue.

2. Unreasonable stacking of rivets

The rivet may show signs of discoloration after tempering, and there may be an oily residue after immersion in ether, indicating that the rivet surface is not clean. Analysis showed that the stacking of the rivets was unreasonable when heated, causing the rivets to slightly oxidize in the quenching oil.

3. Surface residues

The white residue on the high-strength screw was analyzed with the instrument and confirmed to be phosphide. This reaction occurs because the pickling machine was not cleaned and the rinse tank was not thoroughly inspected.

Fourth, alkali burns

High-strength screws are quenched with residual heat and have a relatively uniform and flat oil-black outer surface. After analysis, it was determined to be caused by alkali burns. Therefore, in China, steel rivets cannot form alkaline substances by removing some surfaces in quenching oil, so that the surface is burned at high temperatures in our country, and the injury of students is aggravated during different tempering. Thorough cleaning and rinsing of rivets is recommended prior to heat treatment to completely remove alkaline residues that directly cause rivet burns.

5. Improper rinsing

For large size rivets, it is usually quenched with a polymer solution, washed and rinsed with alkaline washers before quenching. After quenching, the inside of the rivet is rusted. So change the rinse water frequently to make sure the rivets don't rust while rinsing.

6. Excessive rust

Some black streaks are often seen on high-strength rivets, which are surface residues, baking and quenching oil, and contamination from gas phase precipitation during quenching. The quenching oil of the rivet manufacturer is over-aged, and it is recommended to add new oil.