How to Identify 304 Stainless Steel Pipe Quality

 How to Identify 304 Stainless Steel Pipes?

1. Use magnets to identify 304 stainless steel pipes

Ordinary stainless steel pipes have strong magnetism, but 304 stainless steel pipes are non-magnetic or weakly magnetic. Take a magnet close to an ordinary stainless steel pipe and a 304 stainless steel pipe, and you can clearly feel the difference in magnetic force between them, and you will know which stainless steel pipe is the real 304 stainless steel pipe.

2. Identification with copper sulfate

Remove the oxide layer on the steel, put a drop of water on it, and rub it with copper sulfate. If it does not change color after rubbing, it is generally stainless steel; if it turns purple-red: it is non-magnetic and high-manganese steel, and magnetic ones are generally ordinary steel or low-alloy steel.

For steel grades with special properties, we also need to adopt the following three methods for identification. Cold worked chromium-nickel stainless steels, if magnetic, can be cooled naturally by burning small pieces in a fire or placing them in water (annealing). Typically, after annealing, the magnetic properties are significantly reduced or completely eliminated. However, some chromium-nickel stainless steels contain more ferrite elements, and a considerable part of their internal development organization is ferrite. Therefore, it is magnetic even in the hot-worked state.

3. Test solution identification

Stainless steel testing liquid: also called stainless steel pipe testing solution. First, make sure there is no stain on the surface of the 304 stainless steel pipe. After grinding off the surface coating, add a drop of testing liquid to remove the coating. Observe the color change of the 304 stainless steel pipe in the test area, and compare the color of the 304 stainless steel pipe or the time it turns red to make a judgment.

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