People often think that "stainless steel" is "stainless steel". If it rusts, it must be a fake and shoddy product. This understanding is of course too simple. First of all, stainless steel is not absolutely stainless, but relatively stainless under certain conditions. If users use it improperly and use it in an environment or under conditions beyond their corrosion resistance, it will naturally rust. Second, the stainless steel used in the product is corroded and rusted, or it may be because the manufacturer's material selection is unreasonable, that is, the manufacturer chooses an inappropriate stainless steel brand as the raw material for its products, or the manufacturer's production and processing technology is not up to standard. In addition, the manufacturer did choose fake stainless steel that did not meet the authoritative standards of relevant countries or industries as raw materials. In any case, these are what manufacturers have to face and solve when purchasing and processing. In view of the fact that inferior stainless steel is still produced and sold in the market at present, as well as market cheating behaviors such as shoddy and forged quality certificates, how to take the initiative in the procurement of stainless steel materials, quickly see through these cheating behaviors and avoid the harm of fake and shoddy stainless steel? Even as an expert, it is difficult to distinguish the true and false stainless steels from the appearance. Is there any simple method? Some people say: this is very simple, use a magnet to suck! What can't be absorbed is good, it is "stainless steel", and what can be absorbed is poor, it is "stainless steel"! At present, this statement and practice seems to be very popular, and even scientific and technological publications and TV programs have implemented this law. Experts in the industry deny that this statement and practice is unscientific and extremely wrong. At present, among the five types of stainless steel developed and applied in the world, only austenitic stainless steel (numerous 300 series brands and 200 series brands) often has no magnetism (or its magnetism is weak after processing), while ferritic stainless steel (numerous 400 series brands), duplex stainless steel, martensitic stainless steel and precipitation hardening stainless steel all have magnetism. No matter whether it is magnetic or not, each stainless steel has its own characteristics and scope of application. 300 series austenitic stainless steel is the most widely used, and the proportion of stainless steel with magnetic modern ferrite is increasing, which can partially replace 300 series austenitic stainless steel in kitchen utensils, household appliances, decoration, automobile exhaust system, petrochemical industry and other civil and industrial fields. For 200-series austenitic stainless steel whose magnet can't attract, manganese and nitrogen are used instead of nickel, which reduces the cost and improves the strength compared with the corresponding 300-series steel. However, due to the decline of corrosion resistance, its application fields are narrow, often those fields that require high strength, non-magnetism and low corrosion resistance, such as springs and electronic equipment. As for the so-called "200 series stainless steel" popular in China market, its corrosion resistance and use value are lower. These products are not produced according to the existing national standards, but according to their very loose enterprise standards, reducing the content of nickel and chromium in steel and increasing the content of manganese. Some even reduce nickel to below 1%, chromium to below 10%, and manganese to above 14%, and their pitting equivalent is extremely low, far from reaching the corresponding national standards. In terms of corrosion resistance, these products can't even be called stainless steel, nor can they be called 200 series stainless steel at all. In the current stainless steel market in China, it can be said that there are almost no real 200 series stainless steels. The so-called "200 series stainless steel" on the market is the biggest problem steel and fake steel at present, but it is just like 300 series austenitic stainless steel that is nonmagnetic austenitic steel! It can be said that in the current China market, using magnet attraction to identify the quality of stainless steel often connives at fake and shoddy stainless steel and crowd out high-quality magnetic ferritic steel. At the same time, due to cost factors, it will crowd out nonmagnetic 300-series austenitic stainless steel, and may even make this fake and shoddy steel pass off as nonmagnetic 300-series austenitic stainless steel for industrial use. Obviously, it is impossible to identify the authenticity of stainless steel by magnetic attraction. Is there any other practical and simple method? The answer is yes. This paper introduces a simple method, that is, identification with stainless steel measuring solution, that is, by observing the color change characteristics of the measuring solution in the process of dissolving the measured steel, to determine or distinguish some situations of the measured steel. The "color change" is usually related to the specific elements such as nickel (Ni), molybdenum (Mo) and manganese (Mn) in the tested steel. At present, there are many stainless steel measuring liquid products on the domestic market, some of which are imported from Japan and many of which are made in China. Especially in the developed areas of domestic stainless steel industry and stainless steel waste recycling industry, such as Dai Nan, Wuxi, Foshan, Guangdong, Ningbo and Zhejiang. , there have been some manufacturers specializing in the development of stainless steel measuring fluids, and some enterprises engaged in chemical technology and chemical reagents have also developed stainless steel measuring fluids for the needs of the stainless steel industry. At present, although there are many brands of stainless steel measuring fluids in China, the products seem to be the same, which can be basically divided into two categories: those without batteries and those with batteries. Those that do not need batteries are often not subdivided, mainly by observing and measuring the color changes of droplets on the surface of stainless steel, and then distinguishing them by chromatography. For example, there is a model 304 on the market marked with four standard colors, which correspond to four stainless steel brands-20 1, 202, 30 1, 304, where 201corresponds to deep red, 202 corresponds to red, and 30 1 corresponds to light red. These colors refer to the colors that appear when the corresponding steel grade is tested with this measuring solution. There are many battery measurement schemes in the market, such as "Mo2, low Ni, Ni2, Ni4, Ni6, Ni8, Ni 14, Ni20, Ni40, Ni60" and so on. Some products use "n" instead of "Ni" on the label. When these products are used alone or in combination, the approximate content (percentage) of corresponding elements such as nickel (Ni), molybdenum (Mo) and manganese (Mn) in steel can be determined, and then the quality of steel can be judged according to relevant authoritative national standards. For example, when using "Ni8" to measure the solution, first drop a proper amount of "Ni8" medicine solution on a clean steel surface, and then connect the anode of a special battery (generally 9V, which can be distributed by the manufacturer) with the steel plate, and the cathode with the "Ni8" medicine bead on the steel surface (be careful not to touch the steel surface). After a few seconds, stop the power supply and observe the color change of the beads on the steel surface. If the color turns red, such as "low nickel" solution, it is a powerful weapon to determine low nickel and high manganese stainless steel. If the beads are purplish red after electrified oxidation, it means that the manganese content in steel is above 6% and the nickel content is generally below 5.5%. If charged oxidation is colorless or light yellow, it is generally made of 30 1, 304, 430 and other materials. Another example is the "Mo2" measuring solution. If the red complex generated by electrified oxidation does not fade, it means that the molybdenum content in steel is about 2% or above ... The usage of each product will be introduced in detail in its instruction manual. Using stainless steel measuring liquid, we can easily see through some cheating behaviors in the market, and we can also see through the true face of fake and shoddy stainless steel to a certain extent. For example, if we want to buy 304 brand stainless steel, we can test the "304" products provided by the manufacturers. If it is true 304, test it with the above-mentioned "Type 304" measuring solution or "Ni8" measuring solution, and corresponding test results should appear; Otherwise, it is not true 304; If the beads are found to be purplish red by further detection with the "low Ni" measuring solution, it means that the product is a steel with high manganese content, and it is probably a fake stainless steel with low corrosion resistance, which is called "200 series stainless steel" popular in the market at present. When using measuring liquid to measure the approximate content of specific elements in stainless steel for related testing and identification, we need to refer to and understand the provisions on chemical composition in relevant national standards for stainless steel. At present, the identification of stainless steel with stainless steel determination solution only answers the question of "what is not" to a certain extent, but can't really answer the question of "what is". For example, if the so-called "304" product is tested with "304" measuring solution or "Ni8" measuring solution, if the test result is the same as the real 304 product, we can never conclude that it is 304, but can only say that it is "possible". The test result is only a necessary but not a sufficient condition for us to judge that the tested steel is a certain steel type (such as 304) because of whether it is electrified or not. If we really want to find out the exact brand of Chu Gang, we must comprehensively determine its chemical composition through professional chemical analysis or spectral analysis, and then identify it against relevant authoritative standards. Of course, these methods are more professional and accurate than using stainless steel to determine solutions, but they are also more difficult or expensive. In addition, the quality of stainless steel is not only determined by its chemical composition, but also related to its structure, performance, purity and other factors. For the determination of these factors, the stainless steel measuring liquid is obviously powerless, and can only rely on relevant professional testing. At present, the products of stainless steel measuring liquid on the market are not scientific enough in identification and other aspects. As mentioned above, when "N" is used instead of "Ni", some 200 series stainless steels are divided into "200,201202" and so on. In the actual use process, it is also found that some detection results are difficult to distinguish with naked eyes, which is easy to lead to errors. For example, there is obvious color difference between 20 1, 202 and 30 1, 304, but the color change between 20 1 and 202 and between 30 1 and 304 is not obvious. These unscientific and inadequate places need further improvement by relevant manufacturers. In any case, when buying stainless steel products, we should not only pay attention to the factory inspection certificate or quality certificate of the products, but also pay attention to the reputation of the merchants, not greedy for petty gain. In addition, we can also take some initiatives to see through the deception of the market and the true face of fake and shoddy stainless steel products. At present, the small bottles of stainless steel measuring liquid on the market are small in size, light in weight, convenient to carry, low in cost (the price of each bottle ranges from ten yuan to twenty or thirty yuan, and the cost of each test is only a few cents), and the test operation is very simple, which can be regarded as a powerful tool and "weapon". We might as well try.