Fastener knowledge: six points should be paid attention to when maintaining cylindrical head welding nails

The so-called cylindrical head welding nail refers to a high-strength steel connection fastener, and it is also one of the important parts in the machine. Therefore, it must be regularly maintained during use, so as to better protect the cylindrical head The performance of welding nail fasteners allows the machine to operate normally. What do you need to pay attention to when maintaining cylindrical head welding nail fasteners? China Standard Parts Network made the following introduction.

1. Pollution during rinsing

Fasteners need to be cleaned with silicate cleaner after quenching, and then rinsed, so be very careful when rinsing to avoid showing residue.

2. Unreasonable accumulation of fasteners

After tempering, the fasteners will show signs of discoloration. After soaking in ether, there will be oily residues, indicating that the appearance of the fasteners is not clean. The analysis shows that the fasteners accumulate unreasonably when heated, which causes the fasteners to show subtle oxidation in the quenching oil. (Guide: Why are the connecting rod bolts of diesel engines easy to break?)

3. Exterior residues

There is a white residue on the high-strength screw, which was analyzed with an instrument and confirmed to be phosphide. This reaction occurred because the acid cleaner was not cleaned, and the rinse tank was not thoroughly inspected.

Fourth, alkali burns

High-strength screws are blackened by quenching heat and have a uniform and flat oil-black appearance. It is caused by alkali burn through detection. Therefore, the surface alkaline substance cannot be removed in the quenching oil of steel fasteners, which will cause the appearance of burns at high temperatures and aggravate the damage during tempering. It is recommended to thoroughly clean and rinse fasteners before heat treatment to thoroughly remove the alkaline residues that cause fasteners to burn.

Five, improper rinsing

Regarding large standard fasteners, they are often quenched with polymer aqueous solution. Before quenching, they are cleaned and rinsed with an alkaline cleaner. After quenching, the fasteners have rusted on the inside. Therefore, the rinsing water should be exchanged frequently to ensure that the fasteners will not rust during rinsing.

Six, excessive corrosion

High-strength fasteners often see some black streaks. The black streaks are the contaminants of the external residues. The quenching oil is the evolution of the gas phase during the quenching process. Because the quenching oil is over-aging, it is recommended to join the new oil.

More related stamping hardware machinery industry news: