Quality Requirements for Seamless Steel Pipe

Quality requirements for seamless carbon steel pipe
1, Chemical composition
In order to improve the uniformity of chemical composition in steel and the purity of steel, to reduce the non-metallic inclusions in the tube and to improve the distribution state, it is often used to improve the chemical composition of the steel, such as As Sn Sb Bi Pb and gas NHO. External refining equipment for refining of molten steel, and even the use of electroslag furnace on the tube re-melting refining.
 
2, Dimensional accuracy and shape
The geometry of the seamless steel pipe mainly includes the outer diameter, wall thickness, ellipticity, length, curvature, pipe end face inclination, groove angle and the blunt edge, cross-sectional size of the steel pipe.
 
3, Surface quality
The standard specifies the requirements for the "smooth surface" of seamless steel tubes. Common defects include: cracks, hair lines, inside the fold, outside the fold, rolling broken, the straight, outside the straight, separated layer, scar, pits, convex package, Ma Hang (Ma) , The spiral Road, outside the spiral Road, Green Line, correction concave, such as roller. Crack, slight internal and external straight, minor internal and external spiral, straightening, and so on. In addition to the internal and external cracks, cracks, broken, rolling, Concave, roll as a general defect of structural steel pipe.
 
4, Physical and chemical properties
Including mechanical properties at room temperature and mechanical properties at certain temperatures (heat and low temperature properties) and corrosion resistance (such as anti-oxidation, water erosion, acid and alkali resistance and other properties) under normal circumstances depends on the chemical composition of steel, Performance and steel purity and steel heat treatment methods. In some cases, the rolling temperature and the degree of deformation of the steel pipe will also affect the performance of the steel pipe.
 
5, Process performance
Including flaring, flattening, crimping, bending, pulling and welding performance.
 
6, Microstructure
Including the low-power mild steel pipe and high-power organization.

7, Special requirements
In the user's use of steel pipe other than the standard requirements.