How to testing stainless steel screws

Generally, stainless steel screws are directly produced from the factory, but customers will put forward some surface treatment requirements, which can meet their own engineering requirements, and improve the performance of some aspects of stainless steel screws.But how to test these stainless steel screws after surface treatment?After all, customers need qualified products that meet their own requirements.Below we list some methods that can be tested from four aspects.

First  

we start by examining the simplest aspects of appearance quality.Stainless steel screws after surface treatment, we can first use the naked eye can confirm the appearance, coating and other aspects of inspection;

Second

It can be used to check the thickness of the screw coating.

A. measuring method: use vernier caliper, spiral micrometer, plug gauge and other tools to detect the coating thickness of screws;

B. Magnetic method: the coating thickness is measured by this method. In fact, the non-destructive measurement of the non-magnetic coating layer on the magnetic substrate is made by using a magnetic thickness meter;

C, microscopy: this method of measurement is also known as metallography. A metallographic microscope with a micrometer eyepiece magnifies the corroded stainless steel screws and measures the thickness of the coating on the section.

D. Timing flow method: this method calculates the thickness of the coating based on the dissolution time. The specific operation method is to pour the solution that can dissolve the coating on the local surface of the coating, and write down the time when the local coating is dissolved, so as to calculate the thickness of the coating.

In addition, there are coating hair, anodic dissolution coulomb method.

Third, 

Check the adhesion strength of the screw coating.Of course, there are many ways to test coating adhesion strength, here we list six commonly used methods.

A. file method test;

B) scratch method;

C) bending test;

D) bending test;

E, extrusion method;

F. Friction polishing test.

A. measuring method: use vernier caliper, spiral micrometer, plug gauge and other tools to detect the coating thickness of screws;

B. Magnetic method: the coating thickness is measured by this method. In fact, the non-destructive measurement of the non-magnetic coating layer on the magnetic substrate is made by using a magnetic thickness meter;

C, microscopy: this method of measurement is also known as metallography. A metallographic microscope with a micrometer eyepiece magnifies the corroded stainless steel screws and measures the thickness of the coating on the section.

D. Timing flow method: this method calculates the thickness of the coating based on the dissolution time. The specific operation method is to pour the solution that can dissolve the coating on the local surface of the coating, and write down the time when the local coating is dissolved, so as to calculate the thickness of the coating.

Fourth

 This point is the same as ordinary stainless steel screws, coating corrosion test.

We list some corrosion resistance test methods :a, corrosion paste corrosion test (CORR test);

B) atmospheric exposure test;

C, neutral salt spray test (NSS test);

D) acetate fog test (ASS test);

E, copper accelerated acetate fog test (CASS test);

F. Occasional corrosion test;

G, solution drop corrosion test;

H, dip test.

Through the above four aspects to test the surface treated stainless steel screws, can basically determine whether the surface treated stainless steel screws meet customer demand.