There are many kinds of faucets made of materials, from the earliest iron and plastic, to brass, zinc alloy, stainless steel, and now you can see jade faucets and ceramic faucets on the market. Iron is easy to corrode, rust harms health, iron faucets have slowly withdrawn from the market, but in remote villages and towns, iron faucets are still very common in hardware stores. Plastic is not a metal material, the faucet made is not durable, and its application scope is very small. Plastic faucets can be bought in shops selling plastic pipes. Jade faucet is not really used to make water faucet. Jade is only used to decorate the surface, and the base material is mainly brass. Ceramics are not really suitable for faucets. Ceramic products are so brittle. If they are used to make faucets, they will bear a lot of water pressure every day. They are worried that they will burst one day. The main faucets on the market are brass, zinc alloy and stainless steel.
Three main materials
Zinc alloys are generally based on zinc, adding low-temperature zinc alloys such as aluminum, copper, magnesium, cadmium, lead, titanium, etc. The plasticity of zinc alloys is very good, which can produce different styles and shapes, and the corrosion resistance of zinc alloys in the atmosphere can also be, so zinc alloys are generally used to manufacture tap handles. At present, both domestic and European and American markets, taps.
The handles are mainly made of zinc alloy.The corrosion resistance of zinc alloys in the atmosphere is good, but the corrosion resistance of zinc alloys in water is not good. The corrosion resistance of zinc alloys in water also depends on the purity of zinc. If the super-high purity zinc is used as the basis, and the super-high purity aluminum, magnesium and copper alloys are prepared, they also have certain corrosion resistance in water. The problem lies in the influence of price and the temptation of profit. Many manufacturers use zinc alloys containing elements such as lead, cadmium and tin that exceed the standard. The solubility of lead, tin and cadmium in zinc alloys is very small, and it is easy to promote the electricity between zinc alloy crystals in water. Chemical corrosion, and this corrosiveness is very fast, casting is easy to rot.2
The brass used for faucets is about 59% copper, 0.8% to 2% lead, 2% other elements and impurities, and the rest is zinc. It is generally considered that this kind of brass is more suitable for faucets. The brass content of Hpb59-1 is similar to that of the national standard. It is necessary to add lead to brass. The brass with lead increases the machinability and is very needed in processing. But the problem is that lead can not be incorporated into brass crystals, that is to say, lead dissociates between brass crystals. When brass is put into water, it will lead to lead precipitation, which pollutes the water source.
At present, there is no good solution to the problem of lead precipitation from brass faucets, but qualified brass faucets lead precipitation is very few, which is less than the lead content of automobile exhaust that we cross the road every day. Since 2013, the market has exaggerated the negative propaganda of brass faucets containing lead. I think the main reason is that just that year, stainless steel faucets began to enter the market, and the technology is just mature, exaggerating the bad side of brass faucets, which is just in favor of stainless steel faucets. There are more or less brands of stainless steel faucets or manufacturers behind this event, leading to most of them. Consumers magnify the negative.
3,304 Stainless Steel
304 stainless steel is widely used. It is an austenitic stainless steel containing chromium and nickel. The standard 304 stainless steel contains about 18% chromium and 8% nickel. It also contains a small amount of other elements. The remaining amount is iron. 304 stainless steel itself does not contain lead, may carry a little bit in the process of processing, so 304 stainless steel tap lead precipitation is very little, can be neglected. 304 stainless steel has a strong corrosion resistance, no matter in the atmosphere or in water, 304 stainless steel hardly rusts. This is due to its high content of chromium, which passivates the surface of stainless steel and forms a protective film to protect the matrix from oxidation corrosion. Experiments show that only when the chromium content of stainless steel is 12% or more and a certain amount of nickel is added, can the passive film on the surface of stainless steel remain stable, otherwise stainless steel will be oxidized and rusted.
In addition to the advantages mentioned above, the faucet made of 304 stainless steel has another advantage: no electroplating, directly polishing the surface of the faucet, so that stainless steel can show its own characteristics. This advantage alone greatly reduces the production cost of stainless steel faucets. If the brass faucets are polished, electroplating is needed. If the electroplating parts are in trouble, a good faucet will become an unqualified product. There will be no problem with 304 stainless steel faucets. In this way, faucets made of 304 stainless steel seem perfect, but this is not the case.
We all know that chromium is also a heavy metal, but ordinary chromium metal is harmless, there is a substance called hexavalent chromium, contact with the skin may lead to skin allergies, and hexavalent chromium is easily absorbed into the body, may cause genetic defects, long-term inhalation of large amounts of hexavalent chromium, will lead to renal failure, damage liver function and even cause cancer. In this way, the harm of hexavalent chromium is not less than that of lead. 304 stainless steel material contains high chromium content. In CCTV’s clarification program, only two stainless steel faucets were sampled, one of which is chromium hexavalent precipitation exceeding the standard. Therefore, 304 stainless steel faucets are not perfect either. In terms of corrosion, 304 stainless steel does perform well in most environments, but it also has something to fear, that is, chloride ion, chloride ion on stainless steel will produce stress corrosion, is a very strong corrosion. That’s the problem. Most water plants in China use chlorine gas to disinfect. That is to say, chloride ion exists in tap water for a long time. So whether 304 stainless steel tap can stand the test, there are no relevant tests and reports, and we can’t judge.
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