What is the difference between food-grade 304 stainless steel and ordinary stainless steel ?

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

1、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 to use a lot of acid and alkali, and stainless steel contains chromium, unqualified stainless steel, will dissolve a variety of valence of chromium, toxic; and the requirement to limit the content of lead, cadmium and many other alloy impurity elements.

2、the difference between food-grade stainless steel and 304 stainless steel
When stainless steel products in use migration of heavy metals exceed the limit, may endanger human health.
Therefore, stainless steel cookware production, the need to find a balance between corrosion prevention and safety. If the nickel and chromium content is high, the corrosion protection is enhanced, but the ensuing nickel and chromium precipitation is also increased, meaning an increased safety risk.
It is for this reason that the national food safety standard "Stainless Steel Products" (GB9684-2011), makes strict provisions for the precipitation of a variety of heavy metals such as chromium, cadmium, nickel and lead in cookware.

3、why does the national standard not specify the migration limit of manganese?
One reason is that, as the manganese content of stainless steel increases, it is accompanied by a loss of functionality such as corrosion resistance and rust resistance, and once the manganese content reaches a certain value, the product cannot be used as a cookware or cannot be called stainless steel cookware. However, even at such high levels, there are generally no health effects.
Therefore, although the national food safety standards do not specify the manganese content, they do specify that the main part of the utensil container must be made of stainless steel that meets the national standards.

4、Food-grade stainless steel is the stainless steel that meets the GB9684 standard
Food-grade stainless steel, also known as "GB9864 stainless steel", is the stainless steel material that has passed the National Standard of the People's Republic of China/Stainless Steel Sanitary Standards for Food Containers GB 9684-2011, which has a much lower "lead" content than ordinary stainless steel. The content of lead is much lower than that of general stainless steel, and the anticorrosive properties of the product have increased, requiring: lead (as Pb), mg/L in 4% acetic acid immersion solution ≤ 1.0 1.0 . Chromium (as Cr), mg/L 4% acetic acid soaking solution ≤ 0.5. Nickel (as Ni), mg/L 4% acetic acid soaking solution ≤ 3.01.0. Tin (as Sn), mg/L 4% acetic acid in solution ≤ 0.02 0.02 . Arsenic (as As), mg/L in 4% acetic acid solution ≤ 0.04 0.04 . Note: The soaking conditions are all boiling for 30min, then room temperature for 24h.
304 stainless steel is a very common stainless steel, also called 18-8 stainless steel in the industry. It has better corrosion resistance than 430 stainless steel, is resistant to corrosion and high temperatures and has good processing properties, so it is used in industrial and furniture decoration industries and in the food and medical industry, for example: some stainless steel tableware, bathroom kitchen utensils.
304 is a general purpose stainless steel which is used to make equipment and machine parts that require good all round performance (corrosion resistance and formability).
In order to maintain the inherent corrosion resistance of stainless steel, the steel must contain more than 17% chromium and 8% nickel.
General 304 stainless steel is not food grade, special processed food grade.

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