What points should be paid attention to when maintaining the cylindrical head welding nails of fasteners?

Cylinder head welding nail is a kind of fastener with high strength and rigidity connection, and it is also an important part of machinery, so it needs regular maintenance. Only when the maintenance is done, can we ensure the best performance and the best mechanical performance of the fastener cylinder head welding nail. However, some matters need to be paid attention to in the maintenance of the conical head welding nails of fasteners, which mainly include the following six points.

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: Four major inspections of stainless steel screws after treatment)

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 after quenching with a uniform and flat oil-black appearance. It is caused by alkali burn through detection. Therefore, the surface alkalis 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 rust

High-strength fasteners often see some black streaks. This black streak is the contaminant of the external residues. It is the quenching oil that has been dried. It is the evolution of the gas phase during the quenching process. Because the quenching oil is excessively aged, it is recommended to participate in the new oil.

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