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Big Round Head Screw small class explanation: knowledge of screw quality control!

(Summary description)The surface of the product is not allowed to have partial non-plating, scorching, roughness, dullness, peeling, skinning, and obvious streaks, and no pinhole pitting, black plating slag, loose passivation film, cracking, shedding and serious Passivation marks.

Big Round Head Screw small class explanation: knowledge of screw quality control!

(Summary description)The surface of the product is not allowed to have partial non-plating, scorching, roughness, dullness, peeling, skinning, and obvious streaks, and no pinhole pitting, black plating slag, loose passivation film, cracking, shedding and serious Passivation marks.

A screw is a tool that uses the physics and mathematics principles of the oblique circular rotation of the object and the friction force to gradually tighten the objects and parts. So do you know all about its quality control knowledge? Let’s follow the editor of Big Round Head Screw to get a brief look!
1. Appearance:
The surface of the product is not allowed to have partial non-plating, scorching, roughness, dullness, peeling, skinning, and obvious streaks, and no pinhole pitting, black plating slag, loose passivation film, cracking, shedding and serious Passivation marks.


2. Coating distribution:
With different deposition methods, the way the plating layer gathers on the surface of the fastener is also different. During electroplating, the coating metal is not uniformly deposited on the outer peripheral edge, and a thicker coating is obtained at the corners. In the threaded part of the fastener, the thickest coating is located on the top of the thread, and gradually becomes thinner along the side of the thread, and the thinnest deposit is deposited at the bottom of the tooth. Hot-dip galvanizing is just the opposite. The thicker coating is deposited on the inner corners and At the bottom of the thread, the metal deposition tendency of the mechanical plating is the same as that of the hot dip plating, but it is smoother and the thickness is much more uniform on the entire surface.
3. Adhesion:
Cut or pry off with a solid tip and considerable pressure. If the coating is peeled off in a flake or skin shape before the tip of the knife, so that the base metal is exposed, it should be considered that the adhesion is not enough.
In summary, the editor of Big Round Head Screw tells: Introduction to the quality control knowledge of screws.

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