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Four Kinds of Experimental Methods for Stainless Steel Bar

Shaoxing Huida Metal Factory | Updated: Dec 29, 2016

Four Kinds of Experimental Methods for Stainless Steel Bar

    Stainless steel has been applied to all walks of life, so the choice of material is very important, in order to identify the shoddy stainless steel, you can take certain measures and methods. Four chemical identification methods for stainless steel bars are listed below. 

    1.Magnetic test method - magnetic test method is the most common The most common distinction between austenitic stainless steel and ferritic stainless steel the simplest method, austenitic stainless steel is non-magnetic steel, but the cold press after the cold will have a mild Of the magnetic; and pure chrome steel and low alloy steel are strong magnetic steel.

    2.Nitric acid point test method - a distinctive feature of stainless steel is concentrated nitric acid and dilute nitric acid has inherent corrosion resistance, this performance makes it easily from most other metals or alloys to be distinguished. However, high-carbon 420 and 440 steel in the nitric acid test point is slightly corrosive, non-ferrous metals encountered concentrated nitric acid immediately when corrosion, and dilute nitric acid on carbon steel with a strong corrosive.

    3.Copper sulfate point test method - copper sulfate point test is a quick distinction between ordinary carbon steel and all types of stainless steel the most simple method, the use of copper sulfate solution concentration of 5% -10%, before the point of test, The test area should be completely removed oily or other impurities, and grinding machine or soft cloth grinding a small area, and then test the droplets to the grinding, the ordinary carbon steel or iron in a few seconds will form a layer of surface metal Copper, and point the surface of stainless steel does not produce copper precipitation or show the color of copper.

    4.Sulfuric acid test - sulfuric acid immersion stainless steel can 302 and 304 and 316 and 317 to distinguish. The sample was subjected to fine grinding and was then washed and passivated for half an hour in a sulfuric acid solution having a volume concentration of 20 to 30% and a temperature of 60 to 66C. The volume concentration of the sulfuric acid solution was 10% and heated to 71C , 302 and 304 are immersed in the solution, the steel is rapidly corroded and produces a large number of bubbles, the sample blackens within a few minutes; and 316 and 317 steel samples are not subject to corrosion or corrosion is very slow (no bubbles) Test in 10 to 15 minutes without discoloration. The test can be more accurate if simultaneous comparison of samples with known components is performed at the same time.