Technical requirements for production of seamless steel tubes

Seamless steel tube ovality: indicates the degree of non-circularity of seamless steel pipe.
Seamless steel pipe length: normal length, fixed (times) length, length tolerance
Seamless steel tube bending degree: indicates the twist of the seamless steel pipe: the bending degree of the length of the seamless steel pipe per meter, the full-length curvature of the seamless steel pipe
End section of seamless steel pipe: indicates the inclination of the end face of seamless steel pipe and the cross section of seamless steel pipe

Seamless steel pipe end face angle and blunt edge
Seamless steel pipe surface quality: surface smoothing requirements
Hazardous defects: cracks, inflection, external folding, rolling, separation, crusting, concave, convex hull, etc.
General defects: pits, blue lines, scratches, bumps, slight internal and external straights, roller prints, etc.
Seamless pipe is Strongest amongst all pipes type as it has a Homogeneous structure throughout pipe length.
Seamless pipes are manufactured in a verity of size and schedule. However, there is a Restriction on the manufacturing of large diameter pipe. Seamless pipes are widely used in the manufacturing of pipe fittings such as bends, elbows, and tees.
Various Manufacturing process are explained in detail;

Mandrel Mill Process
In Mandrel Mill pipe manufacturing process, steel billet is heated to high temperature in the rotary furnace. A cylindrical hollow, which is also known as mother hollow, is produced with the help of a rotary piercer and set of roller arrangement that keeps the piercer at the center of the billet. Outside diameter of piercer is approximately that of the inside diameter of the finished pipe. With the help, secondary roller arrangement outside diameter and thickness are achieved.
Seamless steel Pipe Manufacturing Process
Metleader was German engineer who has invented this pipe manufacturing process. The only difference between Plug mill process and Mandrel mill process is that in mandrel method inside diameter is achieved in single pass whereas in Mannesmann multi-stage reduction is possible.