What are the methods to determine the material of stainless steel wire
- 2020-04-21-

Stainless steel wires are all over our lives, such as the springs of ballpoint pens, carts, chains on popular ladies' bags, protective covers for electric fans, pull-back wires for umbrellas, hangers, barbecue racks, barbecue forks, etc. It is made of stainless steel wire with different standards, so here we will explain to you what are the ways to distinguish the raw material of stainless steel wire, so that you can better choose the stainless steel wire that suits you.

1. Magnetic experiment method

The magnetic experiment method is a more common simple way to distinguish austenitic stainless steel from ferritic stainless steel. Austenitic stainless steel is a non-magnetic steel, but it will have mild magnetic properties after cold working under high pressure; while pure chrome steel Low alloy steels are all strong magnetic steels.

2. Nitric acid spot test method

A distinctive feature of stainless steel wire is that it has inherent corrosion resistance to concentrated nitric acid and dilute nitric acid. This function allows it to be easily distinguished from most other metals or alloys. However, high-carbon 420 and 440 steels are slightly corroded during the nitric acid spot test. Non-ferrous metals are corroded immediately when they encounter concentrated nitric acid, while dilute nitric acid is strongly corrosive to carbon steel.

3. Copper sulfate spot test method

The copper sulfate spot test of stainless steel wire is a convenient way to quickly distinguish between ordinary carbon steel and all types of stainless steel wires. The concentration of copper sulfate solution used is 5%-10%. Before the spot test, the experimental area should be thoroughly cleaned of oil. Use a grinder or soft abrasive cloth to polish a small area, and then drop the test liquid to the polished place. Ordinary carbon steel or iron will form a layer of copper on the surface in a few seconds, and try stainless steel. The appearance does not produce copper precipitation or show the color of copper.

4. Sulfuric acid experiment method

Sulfuric acid immersion stainless steel can distinguish 302 and 304 from 316 and 317. The cut edge of the sample must be finely ground, and then cleaned and passivated in sulfuric acid with a volume concentration of 20%-30% and a temperature of 60-66°C for half an hour. The volume concentration of the sulfuric acid solution is 10% and heated to 71°C. Time.