Hot Rolled 6-12m Stainless Steel Round Tube SS304 316 321 Seamless Steel Pipe For Construction Industry

1. Heavy metal content

The difference between food grade 304 stainless steel pipe and industrial pipe mainly lies in the heavy metal content of food grade 304 stainless steel pipe is far lower than the heavy metal content of industrial pipe. According to GB 31604.34-2016 national Standard for Food Safety, Determination of Lead in Food Contact Materials and Products and Determination of Lead migration, it is required that the dissolved lead content of food-grade 304 stainless steel tubes is less than or equal to 0.05 under acetic acid immersion; Industrial pipes, such as martensite stainless steel, do not specify lead content.

2, the surface

The most obvious difference lies in the surface, food grade 304 stainless steel tube surface should reach at least BA level, that is, bright surface; And the industrial pipe has no requirements for the surface, the surface is often rough, the key is high corrosion resistance.

3. Process requirements

For food grade 304 stainless steel pipe in direct contact with food, tube finish is very important. However, the inner wall of the tube needs to be polished and annealed to make the inner wall of the tube smoother and to prevent clogging if there is a liquid medium inside.

Industrial pipes are often used in polluted environments, so they require high oxidation resistance, so they are generally treated with pickling passivation. Pickling passivation can form a dense oxide film on the surface of the tube, which greatly improves the corrosion resistance of the tube.

4. Implementation standards

Food grade 304 stainless steel tube reference standard see QBT 2467-2017 "Stainless steel tube standard for Food Industry"; And the standard of industrial pipe, because of its use is divided into a number of varieties, For example, GB/T 31929-2015 "Stainless Steel Welded Tubes for Ships", GB/T 32569-2016 "Stainless Steel Welded Tubes for Seawater desalination Devices", GB/T 24593-2018 "Austenitic stainless Steel Welded Tubes for Boilers and heat exchangers", GB 30813-2014 Austenitic stainless Steel Welded Steel Tubes for Nuclear Power Plants, etc.

In the above standards, the main provisions of food 304 stainless steel pipe surface roughness and health requirements, and the main provisions of the industrial pipe chemical element content, mechanical properties, size, shape, etc..

5. Scope of application

Food grade stainless steel tube is mainly used in food, beverage, wine, medicine and other production equipment and assembly line; And industrial pipes are often used in boilers, heat exchangers, mechanical parts, sewage pipes, chemical pressure pipes and so on.