Requirements for the processing and application of 304 stainless steel pipes

304 stainless steel pipe from the specifications and appearance properties are very characteristic, the first such wall stainless steel pipe is thicker, the cost and practicality is also higher, but the wall is thin, the processing costs will be substantially increased, in addition to the performance limitation of stainless steel pipe depends on the process, usually seamless steel precision is low, and the pipe wall thickness is not uniform, inside and outside the pipe surface brightness is low and the cost of fixed length is more expensive, pipe inside and outside surface is prone to pitting, black spots and not easily removed, the other 304 detection stainless steel thick wall pipe and the whole type must be carried out off-line processing. Therefore, the stainless steel pipe has shown enough superiority in the field of high pressure and high strength mechanical structure.

The stainless steel pipe is divided into hot rolling, hot extrusion and cold drawing (rolling) stainless steel pipe according to the rolling process. According to the difference of metallographic structure of stainless steel, it mainly includes semi ferrite, half martensitic stainless steel pipe, martensitic stainless steel pipe, austenitic stainless steel pipe, austenitic ferrite system stainless steel pipe and so on.

According to the specifications, the specifications of stainless steel pipes are mainly based on the GB14975-94 stainless steel seamless steel pipe regulations, of which 304 stainless steel thick wall pipes are usually 1.5-10m in length, and the hot extruded steel pipe is larger than or equal to 1m. The wall thickness of the cold drawn (rolled) stainless steel pipe is 0.5-1.0mm, the length is 1.0-7m, the wall thickness is more than 1.0mm, and the length is 1.5-8m.

The diameter of the hot – rolled (hot – Extruded) stainless steel pipe is about 45 types with a diameter of 54-480mm, and a total of about 36 kinds of wall thickness of 4.5-45mm. The diameter of the cold drawn (rolled) stainless steel pipe is 65 of the total of 6-200mm, with a total of 39 kinds of wall thickness of 0.5-21mm.

The inside and outside surface of 304 stainless steel thick wall pipe can not appear cracks, folding, cracking, crack, rolling reduction, separation and surface defects, these defects need to completely remove (unless it is specifically used for mechanical processing, and in use) after the removal of the stainless steel pipe wall thickness and diameter of not more than a negative deviation. Some minor surface defects that do not exceed the allowable negative deviations can not be removed.

The allowable depth of the stainless steel straight path is also required. Hot rolled and hot extruded steel pipes and stainless steel pipes whose diameter is less than or equal to 140mm is 5% larger than the nominal wall thickness. The maximum depth is less than or equal to 0.5mm, and the cold drawn (rolled) stainless steel pipes are not more than 4% of the nominal wall thickness, and the maximum depth is less than or equal to 0.3mm.

The last thing to note is that 304 stainless steel thick wall pipes need to be cut into right angles at both ends before application, and the burrs in the pipe wall are removed.

Source: China Stainless Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)

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