What is the difference between stainless steel wire materials?

Stainless steel wires are all over our lives, such as ballpoint pen springs, cart baskets, chains on popular ladies' bags, protective covers for electric fans, pullback wires for umbrellas, hangers, barbecue grills, barbecue forks, etc. It is made of stainless steel wire of different specifications, so here we will explain to you the methods of distinguishing stainless steel wire material, so that you can better choose the stainless steel wire that suits you.

    1. Magnetic test method

    The magnetic test method is a relatively common and simple method to distinguish austenitic stainless steel from ferritic stainless steel. Austenitic stainless steel is non-magnetic steel, but it will have mild magnetic properties after cold working under large pressure; while pure chromium steel and Low alloy steels are strong magnetic steels.

    2. Nitric acid point test method

    A distinguishing feature of stainless steel wire is its inherent corrosion resistance to concentrated and dilute nitric acid, a property that makes it easily distinguishable from most other metals or alloys. However, the high carbon 420 and 440 steels are slightly corroded during the nitric acid spot test, and the non-ferrous metals are corroded immediately when they encounter concentrated nitric acid, while the dilute nitric acid is strongly corrosive to carbon steel.

    3. Copper sulfate spot test method

    Copper sulfate spot test is an easy method to quickly distinguish ordinary carbon steel from all types of stainless steel wires. The concentration of copper sulfate solution used is 5%-10%. Other impurities, and use a sander or a soft abrasive cloth to polish a small area, and then drop the test drop to the grinding place. Ordinary carbon steel or iron will form a layer of surface metal copper in a few seconds, while the surface of stainless steel is tested. Then there is no copper precipitation or copper color display.

    4. Sulfuric acid test method

    Sulfuric acid immersion stainless steel distinguishes 302 and 304 from 316 and 317. The cut edge of the sample should be finely ground, then cleaned and passivated in sulfuric acid with a volume concentration of 20%~30% and a temperature of 60~66℃ for half an hour. The volume concentration of the sulfuric acid solution is 10%, heated to 71℃ When 302 and 304 are immersed in the solution, the steel is rapidly corroded and a large number of bubbles are generated, and the sample turns black within a few minutes; while the samples of 316 and 317 steel are not corroded or corroded very slowly (no bubbles are generated), The test does not change color within 10 to 15 minutes. The test can be more accurate if samples of known composition are tested simultaneously for approximate comparison.