A, magnetic test

Magnetic test is the difference between annealing austenitic stainless steel and ferritic stainless steel of the most simple way. Austenitic stainless steel is a magnetic steel, but after cold work under big pressure to have mild magnetic; And pure chromium steel and low alloy steel are strong magnetic steel.

Second, the nitric acid test

Stainless steel pipe is a striking feature of nitric acid and dilute nitric acid to the inherent corrosion resistance. This performance make it can easily distinguish from most other metals or alloys. But high carbon steel 420 and 440 in the nitric acid point test is a little corrosion, non-ferrous metal meet with nitric acid corrosion will be immediately. Dilute nitric acid on carbon steel has strong corrosive.

Third, copper sulfate point test

Copper sulfate point test is quick to distinguish between ordinary carbon steel and the most simple way to all types of stainless steel. The concentrations of the copper sulfate solution used for 5 ~ 10%.

In front of the points test, test area should be thoroughly remove grease or various impurities, with soft grinding polishing cloth in a small area, then use to clean up after dropping bottle regional drip copper sulfate solution. Ordinary carbon steel or iron in seconds can form a layer of metal copper surface, while the surface of the stainless steel does not produce copper precipitation or display the color of copper.