What are the quality requirements for seamless steel pipe production

Generally, manufacturers have the following requirements for their quality when producing seamless pipes.

1. Ingredients.
It clearly stipulates the components of hazardous chemical molecules As, Sn, Sb, Bi, Pb and vapor N, H, O, etc., in order to improve the uniformity of the components in the steel and the purity of the steel, and reduce the non-metallic material parameters of the finishing tube. To remove debris and to improve its distribution, out-of-furnace refining equipment is generally used to refine the molten steel, and even electroslag furnaces are used to remelt and refine the finish-rolled tubes.

2. Specification precision and appearance design.
The geometrical specifications of the seamless steel pipe mainly include the diameter, wall thickness, ellipseness, length, bending degree, the inclination of the inner hole of the pipe, the angle of view of the welding seam and the blunt edge, and the cross-sectional specification of the seamless steel pipe of the opposite sex. 

3. Process performance.
The specification requires that the surface of the seamless steel pipe is smooth and clean. The common defects are cracks, hair lines, inward folds, outward folds, rolling, inner straights, outer straights, delamination, scabs, dents, convex hulls, floating. Rust (surface), scratches, inner spiral, outer spiral, blue line, concave correction, roll printing, etc. Among them, cracks, inward folds, outward folds, rolling, delamination, scabs, dents, convex hulls, etc. are risk defects; the surface, blue lines, abrasions, mild internal and external straights, mild Internal and external spiral, concave correction, and roll printing are general shortcomings.

4. Physical properties.
It includes the physical properties at room temperature and the physical properties and corrosion resistance properties at a certain temperature, generally speaking, it depends on the composition of the steel, the mechanical properties and the purity of the steel, and the heat treatment process of the steel. In some cases, the cold rolling temperature and deformation level of the seamless steel pipe will also cause harm to the characteristics of the seamless steel pipe.

5. Use performance.
Includes flaring, flattening, coiling, bending, ring-pulling and electric welding properties of seamless steel tubes.

6. Alloy composition.
High and low-rise structures including seamless steel pipes.

7. Special request.
Provisions beyond those expressly stated in the specification when applying seamless steel pipes.