What is food grade stainless steel?
Food grade stainless steel is in line with the "People's Republic of China National Standard GB9684" stainless steel material. The content of lead chromium is much lower than that of ordinary stainless steel.
Indicators stipulate: Food grade stainless steel refers to the part that is in contact with food food machinery, and the food must meet certain safety requirements. Because to use many food acid production process, chromium stainless steel, unqualified stainless steel, will dissolve various prices of chromium, toxic;And requirements to limit the content of lead, cadmium and other alloy impurity elements.
The difference between food grade stainless steel and 304 stainless steel: the use of stainless steel products heavy metal migration amount exceeds the standard, may harm human health. Therefore, stainless steel cookware production needs to strike a balance between corrosion and safety. When the nickel and chromium content is high, the corrosion resistance is enhanced, but the amount of nickel and chromium precipitates produced will also increase, which increases the safety risk.Because of this, "Stainless Steel products" (GB9684-2011) national food safety standard, cookers chromium, cadmium, nickel, lead and heavy metal precipitation index has made strict provisions.
Why does the national standard not specify the migration limit of manganese?
One reason is that with the increase of manganese content in stainless steel, its corrosion resistance and rust resistance also increase. Once the manganese content reaches a certain level, the product cannot be used as cookware or stainless steel cookware. But even at such high levels of manganese, there are usually no health effects. So while national food safety standards do not regulate manganese levels, they do specify that the main portion of food ware containers must be made of stainless steel in accordance with national standards.
Specific standard
All kinds of food storage containers and food processing machinery should choose austenitic or ferritic stainless steel (1Cr18Ni9Ti,0Cr19Ni9, 1Cr18Ni9, 1Cr17Ni2). For the processing part of the grinding tool drilling tool can also choose Martensianite stainless steel (0Cr13, 1Cr13, 2Cr13, 3Cr13).
Specific physical and chemical indicators are as follows:
Item Austenitic stainless steel ferritic martensitic stainless steel
Lead (in Pb), mg/L 4% acetic acid immersion solution ≤ 1.0 1.0.
Chromium (in Cr), mg/L 4% acetic acid immersion solution ≤ 0.5
Nickel (in Ni), mg/L 4% acetic acid soaking solution ≤ 3.0 1.0.
Cadmium (in Cd), mg/L 4% acetic acid solution ≤ 0.02 0.02.
Arsenic (As), mg/L 4% acetic acid solution ≤ 0.04 0.04.
Note: All soaking conditions are boiled for 30min and then room temperature for 24h.
Food grade stainless steel welded pipe has a wide range of applications, both inside and outside the demand. Stainless steel welded pipe welding treatment is very key, 0.5mm can also achieve the effect of internal casting.
If it is a food grade stainless steel welded pipe under normal circumstances need to be thrown inside and outside, at the same time need to weld grinding and bright annealing. The need for internal and external polishing has nothing to do with wall thickness, only with the application situation. The wall thickness is too thin for internal casting is not too big of a problem, for external casting may be a low pass rate.
If it is welded pipe, it doesn't matter inside and outside. Also look at the diameter of your tube. Seamless tube can't be thrown inside. You can't say that the wall thickness of 0.5 is too thin. Because if you have a 0.5 wall thickness of one meter in diameter, it will not be determined, not pressed flat. So it depends on the diameter of your tube.
Maybe your pipe is too long, the wall thickness is too thin, for internal and external polishing is to see the use of the set, you do not have so high requirements, there is no need to increase unnecessary costs.
