Seamless steel pipe quality requirements in production

1, Chemical composition
In order to improve the uniformity of chemical composition and the purity of steel, reduce the non-metallic inclusions of the tube and improve its distribution, often use the furnace refining equipment for the molten steel Refining, and even the use of electroslag furnace on the tube for remelting refining.

2, Dimensional accuracy and shape
The geometrical dimensions of the seamless steel pipe mainly include the outer diameter of the steel pipe, the wall thickness, the ellipticity, the length, the curvature, the cutting angle of the pipe end, the angle of the groove and the cross section of the blunt edge and the opposite.

3, The surface quality
The standard specifies the "smooth surface" requirements of seamless steel tubes. Common defects are: cracks, hairlines, inside the fold, outside the fold, rolling, within the straight, outside the straight, from the layer, scarring, pits, convex package, Ma Hang (Ma face), scratches (scratches) , Internal spiral, outer spiral, green line, concave, roll and so on. Which is broken, broken, broken, rolling, from the layer, scarring, pits, convex hull and other dangerous defects; steel plum, green line, abrasions, slightly inside and outside the straight, slightly inside and outside the spiral, Concave, roll for the general defects.

4, Physical and chemical properties
Including the mechanical properties at room temperature and mechanical properties at a certain temperature (thermal and low temperature performance) and corrosion resistance (such as oxidation, anti-acid, anti-acid and other properties) under normal circumstances depends on the chemical composition of steel, The organizational properties and the purity of the steel and the heat treatment of steel. In some cases, the rolling temperature and deformation of the steel pipe will also have an impact on the performance of the pipe.