What Are The Requirements For Quality Of Seamless Steel Pipe Production?
What are the requirements for quality of seamless steel pipe production?
Usually manufacturers in the production of seamless steel pipe, its quality has the following requirements.
1. chemical composition In order to improve the uniformity of chemical composition in steel and the purity of steel, the non-metallic inclusions of the tube are reduced and the contents of As, Sn, Sb, Bi, Pb and gas N, H, O and so on are put forward. Improve the distribution of the state, usually the use of furnace refining equipment for refining the molten steel, 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. Surface quality. The standard stipulates the requirements of the surface smoothness of the seamless steel pipe. Common defects are cracks, hairline, inner fold, outer fold, rolling, inner straight, outer straight, separation, seamless steel pipe scarring, pits, convex hull Pit (hemp), scratches (scratches), inner spiral, outer spiral, green, concave, roll and so on. Among them, cracks, inner fold, outer fold, rolling, separation, scarring, pits, convex hulls and other dangerous defects; steel plum, green line, abrasions, slight 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 and corrosion resistance at a certain temperature, generally depends on the chemical composition of steel, seamless steel pipe organizational properties and the purity of steel, as well as the heat treatment of steel and so on. In some cases, the rolling temperature and deformation of the steel pipe will also have an impact on the performance of the pipe.
5. Process performance. Including the flaring, flattening, curling, bending, ring pulling and welding performance of steel pipes.
6. Metallographic organization. Including the low magnification of steel tubes and high power organization.
7. Special requirements. seamless steel pipe In the use of steel pipe made when the requirements of the standard.