304 stainless steel is a food grade stainless steel recognized by the state. It has good corrosion and heat resistance, and is used to manufacture high-grade household products. The alloy content of 304 stainless steel is relatively high, so the price is much higher than that of ordinary stainless steel, which often leads to illegal businesses selling inferior steel as 304 stainless steel products. Non-304 stainless steel products not only have poor antirust performance, but also have adverse effects on health if the products are in direct contact with human body.

Method for distinguishing ordinary steel from 304 stainless steel

1. Use a magnet to identify.

Most common steel has strong magnetism, and 304 stainless steel is non-magnetic or weakly magnetic (the manufacturer does not carry out corresponding heat treatment after cold processing to eliminate magnetism in order to save cost). When the same magnet is close to common steel and 304 stainless steel respectively, it can obviously feel the difference in attraction between them.

2. Identify from color difference.

The surface color of pickled stainless steel is silver white and smooth. But chrome nickel stainless steel is silver white and jade.

Chrome stainless steel is white and slightly gray, with weak luster. But the color of Cr Mn n stainless steel is similar to that of Cr Ni stainless steel and slightly lighter. The surface color of stainless steel without pickling: chrome nickel steel is brownish white; Chrome steel is brownish black; Chromium manganese nitrogen is black (these three colors refer to the color with heavy oxidation).

Cold rolled non annealed chromium nickel stainless steel with silver white and reflective surface. Stainless steel, except yuan steel, is generally white after pickling.

Difference between 201 and 304 stainless steel

1. 201 stainless steel Grade: 1Cr17Mn6Ni5N. 304 stainless steel grade: 06cr19ni10 (or 0Cr18Ni9). Due to the different chromium nickel content and carbon content, 304 stainless steel pipe is a little softer than 201 stainless steel pipe, and 304 stainless steel has better corrosion resistance. 201 stainless steel is mainly used in dry areas and decoration areas with lax quality requirements. 304 stainless steel can be used in bathrooms, kitchens and coastal wet areas.

2. Friction spark identification method: you can ask merchants for their lower corner materials, cut and see sparks. Generally, 202 stainless steel has more manganese, so the spark is very stuffy, with more forks, while 304 stainless steel has brighter sparks and less forks. If possible, it can be sent to a professional quality inspection department for inspection.

3. Special steel inspection liquid medicine, which can be purchased in general hardware stores. 304 stainless steel material, after liquid medicine inspection, does not change color in 3-5 minutes. 201 stainless steel material, liquid medicine will turn dark brown red in an instant. However, such liquid medicine is not effective all the time. If you really doubt the steel grade purchased, it is recommended to go to a formal testing institution.