The pipeline classification and grading, Thick wall seamless steel tube, Steel pipe
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The pipeline classification and grading

The pipe is coupled into the device for conveying gas, liquid or solid particles in the fluid pipe, pipe couplings and valves.

Tubing and Casing, Line Pipes

The pipeline project is a very widely used construction technology, occupies an important position in the construction project, the type of pipeline, mainly in the transport fluid medium for the primary purpose. For example, our daily lives can not be separated from the water supply and drainage, heating with hot water or steam, gas, etc..

Piping ships classified in several different ways, commonly Sorted by press working pressure, operating temperature, the transmission medium of the classification commonly used classification method is as follows:

Pipeline classfication

Class Name  Design Pressure P (mpa)
 vacuum piping  P<0
 low pressure piping  0<P≤1.6
 medium pressure piping  1.6<P≤10.0
 high pressure piping 10.0<P≤42.0

Under pressure in the medium, the pipeline must meet has sufficient mechanical strength and sealing performance. Pipes and piping accessories used in the pipe network as well as the connection way have to be safe and reliable under the action of pressure medium and does not leak tight.

 Class Name  Medium temperature T (℃)
 Low temperature pipes  T<-40 ℃
 Atmospheric pressure pipeline  -40 ℃<T<120 ℃
 Temperature pipeline  121 ℃<T<450 ℃
 High temperature piping  450 ℃<T

Pipe under the effect of temperature in the medium should have a stable and reliable heat resistance to withstand the medium temperature and pressure pipes must be in terms of both heat and pressure to meet the requirements of the pipe network. The interaction of medium temperature and ambient temperature, the pipeline will have a thermal deformation of the pipe to withstand thermal stress.

Pipeline grading
The pipeline classification is based on two parameters of the maximum operating pressure and maximum operating temperature of the pipe network transmission medium to determine the level of the pipeline.
 Grade  operating pressure (Mpa)  operating Temperature (Mpa)
 Ⅰ  P>6.4  T>450        T>-140~-45
 Ⅱ  P>4~6.4  T>350~450   T>-45~-30
 Ⅲ  P>1.6~4  T>200~350   T>-30~-20
 Ⅳ  P≤1.6  T>-20~200



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