1. Out-of-tolerance: If the tolerance exceeds a certain range, the size and accuracy will not reach the standard in the future deep processing or application field. It cannot be used normally
2, cracking: steel pipe cracking will directly cause the most serious quality problems of steel pipe, cracking will be caused by many kinds of, round steel material selection is not standard, not high quality, processing technology is not up to standard in the final straightening process will cause cracking
3. Pits: The production of pits will cause the phenomenon of convex and concave uneven surface. For seamless steel pipe, pits on the inside and outside surface will have a serious impact on the late deep processing.
4, warping: warping problems generally appear in the process of processing, annealing and pickling state is a great influence factor.
5, too much eccentricity: the cause of eccentricity, the biggest impact is in the preliminary processing process, the production of too much eccentricity will directly uneven wall thickness, affect the later processing quality and level.
6, straightness guarantee is not good: special-shaped steel pipe has higher requirements for precision, especially the requirements of straightness, but the straightness requirement is also an indirect reflection of the strength of a manufacturer. Many small factories cannot guarantee other factors such as tolerance requirements in straightness.
