Pressure piping surgery

In China 's steel manufacturing standards , there are structural steel tubing and fluid transport points . Structural steel is mainly used for general metal structures such as bridges, steel frame , etc., it is only required to ensure the strength and stiffness , while the rigor of steel is not required. Steel is mainly used for the transport of fluids with pressure fluid delivery . Pressure pipeline , the media it is often conveyed flammable, explosive , toxic, temperature , pressure medium , it should be used for fluid transport pipe. In practical engineering, procurement and construction, often found instead of using structural steel pipe for fluid transport phenomenon , which is not allowed. GB/T3091 " low pressure fluid galvanized welded steel ", GB/T3092 " welded steel low pressure liquid delivery " standards generally furnace steel welded pipe ( ERW manufacturing also sometimes used ) , in addition to their fluid transport pipe shall outside the seized items , just attach the bend test requirements , the manufacture, inspection requirements of such tubes is relatively low . Their size ranges from 1 / 8 " to 6 " , wall thickness , there are two general level and thicker grade material grades are Q195A, Q215, Q235A, three kinds , suitable for a temperature of 0 ℃ ~ 100 ℃, the design pressure is not超过0.6 MPa water and compressed air systems