cold drawn seamless steel tubes:

Round tube → heating → perforation → Heading → annealing → pickling → Oiler (copper) → multi-pass cold drawn (cold) → Preform → heat treatment → straightening → hydrostatic test (testing) → marker → storage. The method of cold drawn (rolled) seamless steel pipe is more complex than hot-rolled (extrusion of seamless steel pipe). The first three steps of their production process is basically the same. The difference from the fourth step, the circular tube was empty to begin annealing. pickling need to use a special acidic liquid after annealing and oiling. Then followed by a blank tube, multi-pass cold drawn (cold) and then specialized heat treatment. it is necessary to straightening. it is sent by conveyor and straightening the metal detection machine (or hydrostatic test) to conduct an internal flaw. In the interior of the steel pipe,there is some issues such as cracks, bubbles will be detected. Steel pipe quality inspection is also through a rigorous manual selection.

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Mechanical and structural tubes;High pressure boiler tubes and other alloy tubes;

Fluid transmission pipe and lower & Middle pressure boiler tubes;Tubes for ship;

 Precision seamless tubes for Automobiles;High Precision pipes for hydraulic cylinder.