What is the method to identify the authenticity of stainless steel

People tend to think that "stainless steel" is "not rusty steel", if rusty, it must be counterfeit products. This understanding is of course too simple. First of all, stainless steel "stainless", not absolutely rust, but relatively in certain conditions of rust. If the user is not used properly, it will be used in the environment or conditions beyond its corrosion resistance, the natural will rust. Secondly, the stainless steel material used in the product corrosion and rust, may also be due to the manufacturer's selection of unreasonable, that is, the manufacturer for the use of its products and the selection of unsuitable stainless steel grades to do the raw material, may also be the manufacturer's production and processing technology is not pass. In addition, that is, manufacturers do choose the market does not meet the relevant national or industry authority standards of shoddy stainless steel as raw materials. In any case, these are manufacturers in the procurement and processing should be faced and resolved. For the current market does still exist in the production and sale of poor quality stainless steel, as well as the second best, forged quality certificates and other market deception, we are in the procurement of stainless steel materials, how can we take the initiative, and quickly break through these deceptive behaviors, to avoid the harm of shoddy stainless steel? For these may be the same bright stainless steel, to distinguish from the appearance of its true and false advantages and disadvantages, even as an expert is also difficult to do, then there is no easy way to do it? Some people say: this is very simple, use a magnet to suck! Can not be sucked is good, is "stainless steel", sucked is poor, is "stainless steel"! At present, this argument, the practice seems to be very popular, and even scientific and technical publications, television programs have implemented this method. For this statement, practice, industry experts have given the negative, is not scientific and extremely wrong. At present the world has developed five categories of stainless steel applications, only austenitic stainless steel (many 300 series grades, 200 series grades) tend to be non-magnetic (processed or weakly magnetic), while ferritic stainless steel (many 400 series grades), duplex stainless steel, martensitic stainless steel, precipitation hardening stainless steel are magnetic. Whether magnetic or not, each type of stainless steel has its own characteristics and scope of application. 300 series austenitic stainless steel is the most widely used, and the magnetic modern ferritic stainless steel type of use is also increasing the proportion, in the kitchenware products, household appliances, decorative, automotive exhaust systems, petrochemicals and other civil and industrial fields can be partially replaced by the 300 series austenitic stainless steel. For the 200 series of this magnet "can not absorb" austenitic stainless steel, manganese, nitrogen instead of nickel, than the corresponding 300 series of steel to reduce the cost and improve the strength, but because of the decline in corrosion resistance, making its application areas are narrower, often those who require high strength, non-magnetic and corrosion resistance requirements are not high in areas such as springs, electronic equipment, etc.. etc. For the so-called "200 series stainless steel" currently prevalent in the Chinese market, its corrosion resistance and use value is even lower. These products are not produced in accordance with existing national standards, but in accordance with its very strict corporate standards to reduce the steel content of nickel and chromium, increased manganese content, some of which even nickel down to less than 1%, chromium down to less than 10%, manganese increased to more than 14%, its pitting equivalent is extremely low, far from the corresponding national standards. From the corrosion resistance, these products can not even be called stainless steel, can not be called 200 series stainless steel. In the current Chinese stainless steel market, it can be said that there is almost no real 200 series stainless steel, the so-called "200 series stainless steel" on the market is currently the biggest problem steel, shoddy steel, but it is the same with the 300 series of austenitic stainless steel, precisely non-magnetic austenitic steel! It can be said that in the current Chinese market using a magnet to identify the merits of stainless steel, often conniving at shoddy stainless steel, and crowded out the high quality of magnetic ferritic steel, but also due to cost factors crowded out non-magnetic 300 series austenitic stainless steel, and may even make this shoddy steel is counterfeited as non-magnetic 300 series austenitic stainless steel and used in the industry. By using a magnet to identify the authenticity of stainless steel is obviously not good, that there is no other practical and easy way? The answer is yes. Here we introduce a simple method, that is, the use of stainless steel determination of liquid identification, is through the observation of the determination of liquid in the process of dissolving the measured steel color change characteristics to determine or distinguish between some of the measured steel. The "color change" is often related to the measured steel nickel (Ni), molybdenum (Mo), manganese (Mn) and other specific elements. At present, there are many stainless steel measuring solution products on the market in China, some are imported from Japan and other countries, and many are domestically produced. Especially in China's stainless steel industry and stainless steel scrap recycling industry is more developed areas, such as Jiangsu Dinan, Wuxi, Guangdong Foshan, Ningbo, Zhejiang, etc., appeared a number of manufacturers specializing in the development of stainless steel determination of the liquid, and previously engaged in a number of chemical technology, chemical reagent enterprises, but also for the stainless steel industry's need to successively develop a stainless steel determination of the liquid. At present, China's stainless steel determination of liquid although many brands, but the products seem to be the same, basically can be divided into two categories without battery and need to be equipped with a battery. Do not need to use the battery is often not subdivided, mainly by watching the determination of the liquid droplets on the surface of stainless steel color changes, and then compared to the chromatogram to distinguish. Such as the market is known as "304 type", it is marked with four standard colors corresponding to four stainless steel grades --- 201, 202, 301, 304, of which 201 corresponds to dark red, 202 corresponds to red, 301 corresponds to light red, 301 corresponds to light red. 201 corresponds to dark red, 202 corresponds to red, 301 corresponds to light red, and 304 corresponds to colorless or light yellow. These colors are the colors that appear when the corresponding steel grades are tested with the test solution. There are many kinds of measuring liquids for batteries on the market, such as "Mo2, low Ni, Ni2, Ni4, Ni6, Ni8, Ni14, Ni20, Ni40, Ni60", etc., and some products use "N" instead of "Ni" on the logo. N" instead of "Ni". These products can be used alone or with the use of steel determination of nickel (Ni), molybdenum (Mo), manganese (Mn) and other corresponding elements of the approximate content (percentage), and then can be compared to the relevant national authoritative standards to distinguish between true and false steel content. For example, "Ni8" determination of liquid, the use of the first appropriate amount of "Ni8" potion drops on the surface of a clean steel, and then there will be sufficient power of the special batteries (generally 9V, manufacturers can be sold), the positive pole connected to the steel plate, the negative pole is connected to the steel surface on the "Ni8" potion. "Ni8" beads (note that do not touch the steel surface), a few seconds after the power to stop to observe the steel surface of the beads of the color changes, if the color becomes red, it is shown that the steel containing nickel in 8% or so and above, otherwise the color of the beads will become yellowish or unchanged. Again, such as "low Ni" liquid fixed liquid, is a kind of determination of low nickel (Ni) high manganese (Mn) stainless steel powerful weapon, such as energized oxidation of the drug bead was purple-red, indicating that the steel content of manganese in more than 6%, nickel content is generally in the 5.5% or less, such as the energized oxidation of the colorless or light yellow, generally 301, 304, 430 and other materials. Material. Again, such as "Mo2" determination of liquid, such as power oxidation to generate a red complex does not fade, it indicates that the molybdenum content of steel in about 2% or more ...... The use of each product in its instruction manual will have a detailed introduction. The use of stainless steel determination of liquid, we can easily recognize the market to a certain extent, some deceptive behavior and shoddy stainless steel true colors. For example, to buy 304 grade stainless steel, we can provide manufacturers of "304" product testing. If it is really 304, we use the above "304-type" determination of liquid or "Ni8" type determination of liquid testing, there should be corresponding test results, otherwise, it is not really 304; if then "low Ni If further testing with "low Ni" measuring solution found that the beads are purple-red, it shows that the product is a kind of high manganese-containing steel, but also is likely to be the current market prevalence of low corrosion resistance of shoddy stainless steel, the so-called "200 series stainless steel". In the use of stainless steel in the measurement of the approximate content of specific elements in the determination of the liquid for the test identification, we are required to refer to and understand the relevant stainless steel national standards on the chemical composition of the provisions. The current use of stainless steel determination of liquid to identify stainless steel, in fact, only to a certain extent to answer the question of "what is not", and can not really answer the question of "what exactly". For example: with the "304-type" determination of liquid or "Ni8" type determination of liquid test business so-called "304" products, if the test results are the same as the real 304 products, we If the test result is the same as the real 304 product, we can not conclude that it is 304, but can only say "may" be 304, because no matter whether it is energized or not energized, the test result is only a necessary but not sufficient condition for us to judge that the measured steel is a certain kind of steel (such as 304). If we want to really figure out the exact grade of steel, then it is necessary to fully determine its chemical composition through professional chemical analysis or spectral analysis and other methods, and then identify it against the relevant authoritative standards. Of course, these methods are more professional and accurate compared with the use of stainless steel determination solution, but the difficulty or cost is also much higher. In addition, the quality of stainless steel material is not only determined by its chemical composition, but also its organization, performance, purity and other factors. For the determination of these factors, stainless steel determination of liquid is obviously unable to help, only with the help of relevant professional testing and inspection. Stainless steel determination of liquid products on the market at present, in terms of labeling and other aspects of the existence of insufficient scientific places. Such as the above mentioned with "N" instead of "Ni", there will be 200 series stainless steel is divided into "200, 201, 202" and so on. In the actual use of the process also found that some test results with the naked eye is difficult to distinguish, easily lead to errors. Such as testing, in addition to 201, 202 and 301, 304, there is a relatively obvious color difference between 201 and 202, 301 and 304 between the color change is not very obvious. These unscientific and insufficient places need to be further improved by the manufacturers concerned. In any case, we in the procurement of stainless steel products, in addition to pay attention to the product factory inspection certificate or quality certificate, to focus on the credibility of the merchant, and do not want to be cheap, we are in the identification of market deception and shoddy stainless steel products in the true colors, or can take the initiative to take some action. Currently on the market in small bottles of stainless steel determination of the liquid, the volume are smaller, lighter weight, easy to carry, the cost of low-cost (the price of each bottle of varieties ranging from ten to twenty or thirty dollars, the cost of each test is only a few pennies), the test operation is also very simple, is not a powerful tool and a "weapon", we may wish to try.