Seamless Steel Pipe

　　Precision pipe is the carbon, alloy or stainless steel pipe with high precision sizes. Usually it has been made through hot rolling or cold drawn (cold rolling) processes. So precision pipe is a kind of seamless pipe. 　　Key processes in manufacturing the precision steel pipe 　　During manufacturing processes, the key point is to do the annealing for raw materials. 　　Precision steel pipe manufacturing flow chart: 　　Raw Material Inspection – Remove Oxide Layer – Visual Inspection – Heating – Hot Rolling – Pickling and Passivation (Phosphating) – Grinding – Lubrication and Drying – Cold Rolling (Internal and external extraction) – Remove Oil – Ends Cutting – Inspection – Marking – Packing and Storage 　　As we know, most of precision steel pipe has cold drawn and hot rolled process. On the contrast, cold rolling will be more complicated. Not only the pipe need to be continuous rolled by three roller, but also the test have to be done after extrusion, so to guarantee the quality ...