Household stainless steel cutlery can be divided into three levels: 430, 18-8, and 18-10. 430 stainless steel, the composition of iron +12% or more of chromium, can prevent the oxidation caused by natural factors, called stainless steel, but will still rust after long-term use. 18-8, its composition is iron + 18% chromium + 8% nickel, 18-10 its composition is iron +18% chromium + 10% nickel. Chromium is a material that does not rust the product, while nickel is a corrosion-resistant material. The higher the nickel content, the better the quality of the product and the more expensive it is. Strictly speaking, products containing only chromium but not nickel are stainless iron. Products containing both iron and nickel are stainless steel. It is important to choose a stainless steel product to see the code number. If there is no printed code on the product, it is generally a nickel-free product. Since nickel is a diamagnetic material, it is usually possible to use a magnet to try it out when it is purchased. It is a stainless iron product that can be attracted by a magnet, and stainless steel products are not attracted by a magnet. There have been two stainless steel products on the market with the label “201”. The composition of the stainless steel product is totally inconsistent with the relevant standards of stainless steel. However, it appears on the market in the name of stainless steel. On the surface, this product is difficult to distinguish from ordinary stainless steel, and it is non-magnetic and easily confused by consumers. The simplest way to judge it is to make it cheaper. The real high-quality stainless steel must be a one-price, one-off, expensive and expensive reason. Using chemical methods to identify the authenticity of stainless steel, in 100mL of distilled water, add 8g of anhydrous copper sulfate, then add 3 drops of concentrated sulfuric acid, the solution drip on the surface of stainless steel products for 6 minutes, the actual surface of stainless steel products will not change, A layer of red material will be produced on the surface of the unqualified product.
In addition to buying stainless steel products should also pay attention to the following two aspects: a look at the color, black hair color, it is likely to stainless iron; dark red color, it is likely to use manganese instead of nickel. The second hand touch, the edge can not have a burr, the surface is smooth, no scratches, no trachoma.