304 stainless steel pipe is everywhere in our lives, but the stainless steel pipe industry is a mixed bag. Some inferior 304 stainless steel pipe manufacturers are purchasing 304 stainless steel pipes. The real 304 stainless steel tube cannot be recognized by the naked eye, so many friends who want to buy 304 stainless steel tube are asking for help. Step by step, today as a small-scale manufacturer of 304 stainless steel pipe, I will share with you a few 304 stainless steel pipe authenticity judgment methods.
First, 304 stainless steel tube magnetic test
The magnetic test of 304 stainless steel pipe is the easiest method to identify annealed austenitic stainless steel and ferritic stainless steel. Austenitic stainless steel is a non-magnetic steel, but it will be slightly magnetic after cold working under high pressure, while pure chromium steel and low alloy steel are both strong magnetic steels. Of course, different materials have different effects. For example, the magnetic properties of 304 stainless steel pipes and 316 stainless steel pipes are smaller, and the magnetic properties of 201 stainless steel pipes are larger.
Second, 304 stainless steel pipe nitric acid point test
A significant feature of 304 stainless steel pipe is its inherent resistance to concentrated nitric acid and dilute nitric acid. This property makes it easy to distinguish it from most other metals or alloys. However, high-carbon 420 and 440 steels have slight corrosion in the nitric acid point test, and non-ferrous metals will corrode immediately when they encounter concentrated nitric acid. Dilute nitric acid is very corrosive to carbon steel.
Third, copper sulfate point test of 304 stainless steel pipe
The copper sulfate point test is the easiest way to quickly distinguish between ordinary carbon steel and various stainless steel pipes. The concentration of copper sulfate solution used is 5-10%. Before the spot test, the test area should completely remove the grease or impurities on the surface of the 304 stainless steel pipe, sand a small piece with a soft abrasive cloth, and then drop the copper sulfate solution into the removal area with a drop bottle. Ordinary carbon steel or iron will form a layer of copper in a few seconds, while the surface of 304 stainless steel pipe will not produce copper precipitation or show the color of copper.
Fourth, 304 stainless steel tube sulfuric acid test
The above are the four determination methods of 304 stainless steel pipe. I hope they can help you! At the same time, I suggest that when you choose 304 stainless steel pipe, you should choose a reliable and reliable pipe from a large manufacturer, which is safer and more reliable to use.