Stainless Steel Seamless Pipe Manufacturing Process
1. Hot rolling (extruded seamless steel pipe)
Round tube billet → heating → piercing → three-roller oblique rolling, continuous rolling or extrusion → tube removal → sizing (or diameter reduction) → cooling → straightening → hydraulic pressure test (or flaw detection) → marking → storage. The raw material for rolling seamless pipes is round tube billets, which are cut by a cutting machine into billets with a length of about 1 meter and sent to the furnace for heating via a conveyor belt.
The billets are sent into the furnace for heating at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is a key issue. After the round tube billets are taken out of the furnace, they must be pierced by a pressure piercing machine. Generally, the more common piercing machine is a tapered roller piercing machine, which has high production efficiency, good product quality, large piercing and expansion, and can pierce a variety of steel types.
After piercing, the round tube billets are successively subjected to three-roller oblique rolling, continuous rolling or extrusion. After extrusion, they must be removed from the tube and sized. The sizing machine uses a conical drill bit to rotate at high speed into the steel blank to punch holes to form a steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the sizing machine drill bit. Stainless steel pipe, stainless steel seamless pipe, stainless steel mirror pipe, stainless steel welded pipe, welding tee, quick-install plug After the steel pipe is sized, it enters the cooling tower and is cooled by water spray. After cooling, the steel pipe will be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or water pressure test) by the conveyor belt for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, they will be detected.
After the steel pipe quality inspection, it must also pass strict manual selection. After the steel pipe quality inspection, the number, specification, production batch number, etc. are sprayed with paint. And it is hoisted into the warehouse by a crane.
Round tube billet → heating → perforation → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → billet tube → heat treatment → straightening → water pressure test (flaw detection) → marking → storage.
The rolling method of cold drawn (rolled) seamless steel pipe is more complicated than that of hot rolled (extruded seamless steel pipe). The first three steps of their production process are basically the same. The difference starts from the fourth step. After the round tube billet is hollowed out, it needs to be headed and annealed. After annealing, it needs to be pickled with a special acidic liquid. After pickling, oiling. Then it is followed by multi-pass cold drawing (cold rolling) and then billet tube, special heat treatment. After heat treatment, it needs to be straightened.
After straightening, the steel pipe is sent to the metal flaw detector (or water pressure test) by the conveyor belt for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, they will be detected. After the steel pipe quality inspection, it must pass strict manual selection. After the steel pipe quality inspection, the number, specification, production batch number, etc. are sprayed with paint. And it is hoisted into the warehouse by a crane.
