There are mainly the following four inspection methods for stainless steel screw fasteners. China Stud Supplier will give you a detailed introduction:
First, the appearance quality requirements
The appearance inspection of stainless steel screws is carried out from the aspects of appearance, electroplated layer, etc.
Second, the screw coating thickness inspection
1. Measuring method: The amount used includes micrometer, vernier caliper, plug gauge, etc.
2. Magnetic method: The magnetic method is used to measure the thickness of the coated layer. It is a non-destructive measurement of the non-magnetic coated layer on the magnetic substrate with a magnetic thickness gauge.
3. Microscopic method: Microscopic method is called metallographic method. It magnifies the etched fastener on a metallographic microscope with micrometer eyepiece to measure the thickness of the coating on the section.
4. Chronological Flow Method
Chronological flow method uses the solution that can dissolve the plating layer to flow on the local surface of the plating layer, and calculates the thickness of the plating layer according to the time required for the local plating layer to dissolve. There are coating drop method, anodic dissolution coulometry, etc.
Three, screw coating adhesion strength inspection
There are many methods to evaluate the adhesion between coating and base metal, usually the following.
1. Friction polishing test;
2. File test;
3. Scratch method;
4. Bending test;
5. Thermal shock test;
6. Extrusion method.
Four, stainless steel screw coating corrosion resistance inspection
Testing methods for corrosion resistance of coating include: atmospheric explosion test; Neutral salt spray test (NSS test); Acetic acid salt spray test (ASS test) and copper accelerated acetic acid salt spray test (CASS test); And corrosion paste corrosion test (CORR test) and solution drop corrosion test; Immersion test, immersion corrosion test, etc.
For more relevant information, please pay close attention to our fastener manufacturer's website for a long time.