First, the magnetic test

The magnetic test is the simplest way to distinguish between annealed austenitic stainless steels and ferritic stainless steels. Austenitic stainless steel is non-magnetic steel, but after the cold under pressure will have a mild magnetic; and pure chrome steel and low alloy steel are strong magnetic steel. By testing the magnetic properties of steel pipe can be identified austenitic stainless steel pipe and ferritic stainless steel pipe.

Second, nitric acid point test

One of the salient features of stainless steel pipes is inherent corrosion resistance to concentrated nitric acid and dilute nitric acid. This performance makes it easy to distinguish from most other metals or alloys. But the high carbon type 420 and 440 steel in the nitric acid point test is slightly corroded, non-ferrous metals encountered concentrated nitric acid will be corroded immediately. And dilute nitric acid on the carbon steel has a strong corrosive.

Third, the copper sulfate point test

The copper sulfate point test is the easiest way to quickly distinguish between ordinary carbon steel pipes and all types of stainless steel pipes. The concentration of the copper sulfate solution used is 5 to 10%.