Now many industrial products are made of stainless steel wir
Date of issue:2020-01-15 Browse times：994
1. Magnetic test method
Magnetic test is the most original and common method to distinguish austenitic stainless steel from ferritic stainless steel. Austenitic stainless steel is a non-magnetic steel, but it will have slight magnetism after cold working under high pressure. Pure chromium steel and low alloy steel are all strong magnetic steel.
2. Nitric acid point test
A remarkable feature of stainless steel wire rope is its inherent corrosion resistance to concentrated nitric acid and dilute nitric acid, which makes it easy to distinguish it from most other metals or alloys.
However, the high carbon type 420 and 440 steel are slightly corroded in the nitric acid point test, and the non-ferrous metals are immediately corroded in the presence of concentrated nitric acid, while the dilute nitric acid has strong corrosiveness to carbon steel.
3. Copper sulfate spot test
Cupric sulfate spot test is the easiest way to quickly distinguish ordinary carbon steel and all types of stainless steel wire rope. The concentration of cupric sulfate solution used is 5% - 10%. Before spot test, oil or other impurities shall be completely removed from the test area, and a small area shall be polished with a grinder or soft abrasive cloth, and then the test solution shall be dropped to the grinding place. Ordinary carbon steel or iron will form a layer of table within a few seconds The surface of stainless steel does not produce copper precipitation or show the color of copper.
4. Sulfuric acid test method
Sulfuric acid immersion stainless steel can distinguish 302 and 304 from 316 and 317. The cut edge of the sample shall be finely ground, and 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 sulfuric acid solution is 10%. When heated to 71 ℃, 302 and 304 are immersed in the solution, the steel is rapidly corroded and generates a large number of bubbles, and the sample turns black in several fractions; while 316 and 317 steel samples are not corroded or corroded very slowly (no bubbles), and the test is 10 ~ 15 There is no discoloration within the species. If the samples with known components are tested at the same time for approximate comparison, the test will be more accurate.
