“Defense Insulation Cup” hot water into poisonous water, can the magnet inhale the material? not that simple


The weather was getting colder, and the appearance rate of the insulation cup was higher. Whether it is a child in the kindergarten or the middle -aged people in the office, the thermos cup is an indispensable object. It is almost a man, and some cups are still expensive.

There is almost one hand insulation cup


However, the people who use the thermos cup are also a little troublesome. CCTV has repeatedly exposed the chaos in the insulation cup market. The results of the sampling inspection are not optimistic. The stainless steel insulation cups produced by some bad manufacturers are not used in food -grade stainless steel materials. Long -term use will precipitate a large amount of toxic heavy metals. The hot water is poisonous and water, which brings great harm to our health. cup”.


How to judge the materials used in thermal insulation cup, is it safe and reliable food -grade stainless steel? There are many ways to give on the Internet. The simplest of which is to judge through magneticity, that is, inhale with magnets. There is a saying that: with a weak magnetic insulation cup, it must be a toxic material, completely magnetic or strong magnetic. The material is safe and non -toxic.


CCTV has exposed the chaos in the warranty cup market


Can you judge the material of the thermal insulation cup so simple? The fact is far less simple! Let’s take a look at what materials are generally used in the insulation cup. Before this beautiful and easy -to -take, the double -layer insulation cup appeared, people generally use thermos bottle to save boiling water. In fact, their principles are very similar, and they are insulated by the characteristics of poor heat transfer performance of vacuum layer.

There are many controversies who invented the heating water bottle. It is said that there is a patent that the Germans applied for the first application during the Northern Song Dynasty, and some of the Germans were first produced by British scientists to save liquid oxygen. But in any case, the structure of the aquarium bottle is similar: put the two glass bottles together to form the inner bilots, plated the bright silver film on the outer surface and the inner surface of the outside bottle, and then remove the air between the inner and outer bottle. Then put on the shell, a heating water bottle with excellent thermal insulation effect is made.

Why can it keep warm? The reason is to isolate various transmission methods of calories. The heat transfer is nothing more than three ways: heat conduction, thermal radiation, thermal convection. Based on the inner and outer bottles, the heat transmission and thermal convection become extremely weak, while the bright silver -plated layer reduces thermal radiation, which makes the heat water in the inner bottle cannot be passed out, forming a thermal insulation effect. At the same time, the heat outside the bottle cannot be passed on, so it can be kept cold.


Although the warm water bottle is ancient, the insulation effect is good

The thermal bottle made of silver -plated silver, the heat preservation effect is particularly good, but there is a big disadvantage that it is easy to break. I believe that many people have the experience of breaking the warm water bottle. Therefore, some thermal bottle inner biliary uses stainless steel (ordinary carbon steel is easy to rust). It is solid and durable and not easy to damage. However, stainless steel is metal. The heat conduction performance is much stronger than the glass. The insulation effect is not as good as the former.

The principle of the insulation cup is similar to that of the thermal bottle, and it is also used in the middle of the two layers of cups. However, because the small and beautiful thermal insulation cup is not as large as the pot, and it has to be carried everywhere, the advantages of stainless steel that is not easy to break up, and the insulation effect is almost acceptable. Therefore They are all stainless steel, so the possibility of the “killing thermal insulation cup” is generated.

The structure of the insulation cup is similar to the heating water bottle

Many people think that stainless steel will not be rust, and it is always glitter. How can it be toxic when using it as a warming cup? In fact, stainless steel is not completely rusty. It has a large number of cards and can be divided into many types. It mainly includes Austenite stainless steel, martensite stainless steel, ironstone stainless steel, and austenite-ironstone stainless steel. The so -called austenitic and ferrite refers to the micro -tissue structure of the metal.

Stainless steel can resist the corrosion of air, steam and water, and some can also resist acid, alkali and other chemicals. The main reason is that it contains chromium, which changes the potential of the steel and is not prone to electrochemical corrosion. Make many stainless steels from crystal corrosion. (So ​​do not soak your thermos cup with salt water, even 304!)

Do not put salt water in the thermal insulation cup

What we usually call 300 series such as 304 and 316 stainless steel belongs to Austenite stainless steel. It contains a certain percentage of nickel and other elements. Not only is it resistant to corrosion, heavy metals have fewer precipitation, and the processing performance is very good, so it is widely used. Like 304, 316, etc. are all the names of the United States. The domestic brand is named after the proportion of elements. For example, the national bid number of 304 is 06Cr19NI10, but because the US standard number is more memorable and deeply rooted in the hearts of the people, when the material labeling the insulation cup material Usually use beauty standards.


The water in the thermal insulation cup is used to drink. After the stainless steel is corroded, harmful substances may be precipitated, so you must use a qualified food -grade stainless steel. So what is food -grade stainless steel?

The glittering 304 stainless steel pipe

In the impression of many people, 304 and 316 and more corrosive 316L are recognized food -grade stainless steel. The bottom of the cups of various insulation cups often marked 304 or 316, while 201 stainless steel is not. This understanding is not. This understanding is not. Right? Let’s think that it is right, then the question of returning to the beginning: Can you judge whether the thermal insulation cup is 304 or 300 such as 300 series such as 304 or 316?


Theoretically, due to the structure of micro -tissue structure, the 300 series of chromium nickel -type Austeen stainless steel is no magnetic. Domestic low -end 201 stainless steel is used instead of 304 and 316. This stainless steel replaces nickel with a certain percentage of manganese, but it also belongs to the Austenite, which is theoretically no magnetic. Magnetic stainless steel also exists, such as the 400 series mart -generated stainless steel.

Austenitic, martensite, etc. are all micro -gold phase tissue structures

In fact, the Austeen stainless steel will only be unknown after the tissue is completely transformed into the austenite after being solid -soluble. Athhetic, which produces magneticity. The greater the processing amount, the greater the magnetism. In this way, even 304 stainless steel may be magnetic after making a cup. If you want to completely eliminate magneticity, you need to perform heat treatment.

Therefore, if the magnet is used to suck, it cannot be distinguished whether it is 201 or 304 or 316. It is unreliable to determine the material of the thermal insulation cup through the magnet. Magnetism may also be 201, and magnetic ones may be 304. So if the cup material really uses 304 or 316 stainless steel, can it be said to be food -grade stainless steel? This is not necessarily. Let’s take a look at how the “food -grade stainless steel” is defined. The national standard GB9684 says:

The main part of the equipment and food production and operation tools, the main part of the equipment should be made of Austrian stainless steel, Austenite-ferrite stainless steel, iron stainless steel and other stainless steel materials that meet relevant standards; tableware and food production machinery equipment The main part of the drilling tool can also be manufactured by Maz’s stainless steel.

The stainless steel varieties cover this paragraph are quite extensive, and there is no regulation that the austenitic stainless steel such as 304 and 316 must be used, indicating that the type of stainless steel is not the main consideration. This has made a detailed regulation that the material is boiled for 30 minutes under the 4%perception solution, and it is placed at room temperature for 24 hours. value.

The physical and chemical index limit stipulated in the national standard

Therefore, people’s general understanding of food -grade stainless steel is usually wrong. The national standard is not too limited to the material of food -grade stainless steel, but limited the quantity of harmful substances. The corrosion resistance of stainless steel such as 304 and 316 is better, and the amount of heavy metals is less. It is easier to meet the requirements of the national standard. Therefore, it becomes the first choice for food -grade stainless steel. Of course, the prerequisite is also tested. The corrosion resistance of 201 stainless steel is not as good as 304, so it is often used for decoration, and the food industry is less useful.

Some people say that the stainless steel has poor corrosion resistance and high manganese content, which will produce a large amount of heavy metals, which is also uncertain. The high -manganese content of 201 stainless steel does not mean that the precipitated manganese must be high, and the national standard does not specify the quantity of manganese. Of course, 201 is really not suitable for corrosive substances such as carbonated beverages. It is not as good as 304 and 316. The latter two are more insurance. In addition, the cost of stainless steel in 201 is relatively low, and some illegal manufacturers with broken consciences have used 201 to impersonate 304 to obtain higher profits.

Material logo at the bottom of the insulation cup


In short, judging whether the thermal insulation cup is a food -grade stainless steel, the magnet is not reliable, and the card is not accurate. As long as it meets national standards, the stainless steel materials that are qualified for harmful substances such as lead, cadmium, arsenic, etc. Stainless steel”. Conversely, even 304 and 316 stainless steel, if the content of harmful substances is high, it cannot be counted as food -grade stainless steel. In fact, it is difficult for consumers to judge the material of the thermal insulation cup by themselves. In order to avoid being fooled, choosing a big brand is more insurance.