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June 11, 2019

What Is The Difference Between Food Grade 304 Stainless Steel And Ordinary Stainless Steel

Food grade stainless steel refers to the stainless steel material that meets the requirements of the National Standard of the People's Republic of China / Sanitary Standard for Stainless Steel Food Containers, GB 9684-88, and its lead chromium content is much lower than that of ordinary stainless steel.

Indicator regulations

Food grade stainless steel refers to the part of food machinery that comes into contact with food and must meet certain food safety requirements. Because the food production process uses a lot of acid and alkali, and stainless steel contains chromium, unqualified stainless steel, will dissolve all kinds of chromium, toxic; and it is required to limit the content of various alloy impurity elements such as lead and cadmium.

The difference between food grade stainless steel and 304 stainless steel

When stainless steel products migrate in excess of heavy metals during use, they may endanger human health.

Therefore, the production of stainless steel cookware requires a balance between corrosion protection and safety. If the content of nickel and chromium is high, the anti-corrosion function is enhanced, but the amount of nickel and chromium precipitated will also increase, which means the safety risk is increased.

Because of this, "Stainless Steel Products" (GB9684-2011) national food safety standards, strict regulations on the precipitation of chromium, cadmium, nickel, lead and other heavy metals in the cookware.

Why does the national standard not stipulate the migration limit of manganese?

One reason is that with the increase of manganese content in stainless steel, it is accompanied by the loss of functions such as corrosion resistance and rust resistance of the cookware. Once the manganese content is high to a certain value, the product cannot be used as a cookware or stainless steel cookware. It is. But even such a high manganese content generally does not affect health.

Therefore, although the national food safety standard does not regulate the manganese content, it is clearly stated that the main part of the food container must be made of stainless steel material in accordance with national standards.

Food grade stainless steel is stainless steel according to GB9684 standard

Food grade stainless steel, also known as "GB9864 stainless steel", is the stainless steel material specified in GB 9684-2011 under the National Standard of the People's Republic of China / Sanitary Standard for Stainless Steel Food Containers. The lead content of this stainless steel is lower than that of ordinary stainless steel. Much more, the product's anti-corrosion performance has also increased, the requirements are: lead (in Pb), mg / L 4% acetic acid soaking solution ≤ 1.0 1.0. Chromium (in terms of Cr), mg / L 4% acetic acid soaking solution Medium ≤ 0.5. Nickel (in terms of Ni), mg/L 4% acetic acid soaking solution ≤ 3.01.0. Tin (in terms of Sn), mg/L 4% acetic acid solution ≤ 0.02 0.02. Arsenic (as As), mg/L 4% acetic acid solution ≤ 0.04 0.04. Note: The soaking conditions are all boiled for 30 min, then room temperature for 24 h.

304 stainless steel is a very common stainless steel, also known as 18-8 stainless steel. Its corrosion resistance is better than 430 stainless steel, corrosion resistance, high temperature resistance, good processing performance, so it is widely used in industrial and furniture decoration industry and food medical industry, such as: some high-grade stainless steel tableware, bathroom kitchen utensils.

304 is a versatile stainless steel that is widely used to make equipment and parts that require good overall performance (corrosion resistance and formability).

In order to maintain the corrosion resistance inherent in stainless steel, the steel must contain more than 17% chromium and more than 8% nickel.

Generally 304 stainless steel is not food grade, and the special processed food grade.

It is well known that stainless steel products related to “edible” must use 304, 316 stainless steel. 316 stainless steel is expensive and is used in high-end equipment such as aerospace and food machinery. The food grade stainless steel used in daily necessities is mostly 304 stainless steel, which has good acid and alkali resistance and strong corrosion resistance.

In comparison, 201, 202 stainless steel (commonly known as high manganese steel) is generally used in industrial products, not for tableware, because it:

● The nickel content is not up to standard, the acid and alkali resistance is poor, and it is easy to rust;

● Excessive manganese content, excessive intake of manganese in the human body can cause damage to the nervous system.

201 stainless steel contains less nickel, less chromium, weaker anti-corrosion performance, more manganese, better acid and alkali resistance, and cheaper price! In order to maintain the inherent corrosion resistance of stainless steel, 201 stainless steel must contain more than 16% chromium, more than 8% Nickel content. The surface is very bright with dark light, and the manganese is high and it is easy to rust. 304 contains more chromium, the surface is matte and does not rust. The two are put together and there is comparison. The most important thing is the different corrosion resistance. The corrosion resistance of 201 is very poor, so the price is much cheaper. And because 201 contains low nickel, the price is lower than 304, so the corrosion resistance is not as good as 304.

In daily life, our chances of getting in contact with stainless steel products are extremely high, and stainless steel electric kettles are one of them. Which are "201" and which are "304"? It is difficult to distinguish ~

Differentiating these different stainless steel materials, the laboratory method is mainly to detect the composition of the substance. For example, the hand-held fluorescence spectrometer, which is more commonly used by us, can quickly analyze stainless steel of different materials and quickly obtain the content of all elements in the metal composition. There will be obvious differences.

In general: food grade stainless steel refers to the stainless steel material that meets the national GB9684 standard and can be in contact with food without causing physical harm. GB9864 stainless steel is in accordance with the national GB9684 standard certified stainless steel material, so GB9864 stainless steel is food grade stainless steel. . At the same time, the so-called 304 stainless steel is not required to pass the national GB9684 standard certification, 304 stainless steel is not equal to food grade stainless steel, 304 stainless steel is not only used in kitchen utensils, but also widely used in industry, the hazard to the human body is unknown. At the time of purchase, regular products will be marked with “food grade 304 stainless steel” on the surface and inner wall of the product, and the product labeled “food grade – GB9684” will be safer.

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