How to identify 304 stainless steel?

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1. In experimental research: Generally, the components can be analyzed through spectroscopy.

 2. In industry: It can be distinguished by soaking in chemical preparations. There are many kinds of solutions. Here we take the stainless steel pickling passivation solution as an example. (Using The limitation of pickling and passivation screening is that it can only distinguish product series, but cannot refine it to a certain branch) 1). SUS300 series (301/302/303/304...321, etc.) will It gradually turns from the original natural color or mirror color to a matte color, and will not continue to change color after that. 2). SUS200 series (201/202/203/204...) products will instantly turn black after soaking. Blackened products After rinsing, the black film can be touched by hand. If you rub the product with your face, it will appear matte. If you continue to soak it, it will corrode and the product will start to smoke visible to the naked eye. 3). Bubble martensitic stainless steel SUS400 series (410/420/430/440...) After soaking, the effect of the product is similar to that of the SUS200 series. The only difference is that the black film cannot be touched off at all. It needs to be soaked with special liquid to remove the black film. 3. Home screening method: Magnet, just suck it and you will know. This is the simplest and most effective method. SUS304 is a non-magnetic product and cannot be sucked up. SUS200 series will have a slight suction force that can be felt by the magnet. Small products will be sucked up. SUS400 series and iron There is no difference, the suction is very tight (most commonly seen by people who use this method: scrap collectors, who always have a magnet with them), specific to the product, such as a stainless steel thermos cup, the stamp inside is marked SUS304, if you use a magnet to suck it, you will not feel anything. , don’t think about it, it must be 304. Don’t expect it to be 316, titanium or aluminum alloy. The manufacturer is not that stupid. The cost is too high. If the magnet can attract it slightly, be careful. It is most likely 201. Don’t use this kind of cup. If used for a long time, under certain conditions, heavy metals such as manganese, lead, and chromium will precipitate. It is truly a poisonous cup. If the magnet is particularly strong, don’t think about it. It is stainless iron. It is probably a shoddy cup. This kind of cup It is particularly easy to rust. Stainless iron is not suitable for use in products such as pots, pans and cups. It is generally used to make knives. Digression: In order to save material costs, many manufacturers use pots, pans, cups and other products. 201 or stainless steel will also be used. In order to achieve the same stainless and non-corrosive effect as 304, the method of stainless steel electrolytic polishing + stainless steel natural color passivation will be used to increase its anti-corrosion and anti-rust performance by 8-20 times, thereby acting as Of course, for high-end goods, it is not excluded that the purchaser requires this material. If you are interested in improving anti-corrosion and anti-rust, please contact me and I will provide you with a solution for free.