If the material is not good stainless steel, the surface might not be smooth and shiny. But sometimes, the surface looks dark even it’s standard stainless steel.
Why? there are several different reasons.
Firstly, it might be caused by the elements in the stainless steel.
Iron, nickel, and chromium are the mainly elements in stainless steel, and there is a standard range for them.
In same iron content, if the chromium content is higher, the surface will be shinier; if the nickel content is higher, the surface will be darker. In same chromium and nickel content, if the iron content is higher, the surface will be darker.
So it's not a right way to tell if it is standard stainless steel only by checking the surface brightness.
Besides the elements, the surface will be darker if the stainless steel was oxidated during the drawing process.
In the wire drawing process, if the manufacturer didn't use the good lubricant, the stainless steel wire temperture will increase because of the friction. Then the surface will be oxidated by the higher temperture.
That's why we'll check their drawing process and checking the brightness after buying the stainless steel wire, it will affect the final surface looking.
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