Industry Information

How to check the screws?

How to inspect screws;
There are two types of surface inspection for screws: one is the inspection before electroplating after the screws are produced, and the other is the inspection after electroplating, which means the inspection after the screws are hardened and the screw surface is treated.
After the screws are produced and before electroplating, we conduct inspections on dimensions, tolerances, and other aspects of the screws. Check if it meets national standards or customer requirements. After the surface treatment of the screws, we inspect the electroplated screws, mainly for the color of the plating and whether there are any damaged screws.
This way, when we send the screws to the customer, they can smoothly pass the customs when they receive the goods. Inspection after screw treatment:
1、 Appearance quality requirements;
The inspection of screw appearance is carried out from various aspects such as appearance, electroplating layer, etc.
2、 Inspection of screw coating thickness;
1. Measuring tool method;
The amount used includes micrometer, Vernier scale, plug gauge, etc.
2. Magnetic method;
The magnetic method for measuring the thickness of a coating layer is a non-destructive measurement of a non magnetic coating layer on a magnetic substrate using a magnetic thickness gauge.
3. Microscopic method;
Microscopic method, also known as metallographic method, involves magnifying corroded fasteners on a metallographic microscope with a micrometer eyepiece to measure the thickness of the coating on the cross-section.
4. Timing liquid flow method;
The timed liquid flow method uses a solution that can dissolve the coating to flow onto a local surface of the coating, and calculates the thickness of the coating based on the time required for the local coating to dissolve. There are also coating droplet method, anodic dissolution Coulomb method, and so on.


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