Hot-rolling Process of Small-diameter Extra-thin-wall Seamless Steel Pipe

Hot-rolled small-diameter ultra-thin-wall seamless steel pipe, the billets are heated in a heating furnace, pierced into a capillary tube by a perforating unit, conveyed by a feeding mechanism into a mandrel bar mechanism, and put the mandrel into the capillary tube into the six racks In the three-roller hot rolling mill, the rolling is performed synchronously with the mandrel, the 1-2 stands are reduced in diameter, the 3-4 stands are wall-reduced, the 5-6 stand is rounded, and the rolling is extended. The milk is transferred to the rotating mill. After loosening the rod in the rod mechanism, the core rod is taken out from the rod removing machine and sent to the secondary heating furnace for heating, and the micro-strain reducing diameter sizing unit is set. The sizing-adjusted seamless steel tube is cooled after being cooled by the step cooling bed. Straightening, cutting and other steps to form a commodity tube.

Small-diameter special thin-walled seamless steel pipe longitudinal rolling process, the specific process flow is as follows:Step 1: Heating, the tube is heated in a heating furnace, the heating temperature is not less than 1200 degrees;Step 2: Perforate, perforate the perforated unit to perforate the heated tube blank to make a capillary tube;Step 3: Rolling, the capillary tube is fed into the mandrel bar mechanism by a feeding mechanism, the mandrel bar is penetrated into the capillary tube, and is sent to a three-roller six-stand vertical rolling mill, six machines in a three-roller six-stand longitudinal rolling mill In the tandem rolling mill, the rolling is performed synchronously with the wick penetrating the mandrel bar. Among them, the 1 stand tandem mill and the 2 stand tandem mill reduce the diameter and wall of the capillary, and the reduction value is 5mm-10mm. The wall-reducing value Omm-0.5mm, 3-stand mill group and 4-stand mill stand reduce the diameter of the capillary and reduce the wall thickness. The reduction value is 2mm-8mm, and the wall-reducing value is 5-stand mill. The 6-stand rolling mill reduces the diameter of the capillary tube, reduces the wall thickness, sets the circle, reduces the wall thickness by reducing the diameter, and extends the rolling to form the waste tube.Step 4: Loose rods, rolling tube with mandrel, rolling rotary inclined roller, rolling roller rolling mechanism rolling mill; the rotating arc inclined roller, roller compaction In the loose stick mechanism, the barren pipe held on the mandrel is rotated and rolled by the upper and lower rollers to reduce the wall diameter, and the diameter of the barren pipe is increased. After the rotary roller compaction, the bar is separated from the mandrel and the wall thickness of the barren pipe is reduced by 0.1 mm to 0.2 mm. Diameter increase 1mm-3mm;Step 5: Detach the stick, put the waste pipe with mandrel after loose rolling, and send it into the de-sticking mechanism. Use two rollers to grind the mandrel longitudinally to remove the mandrel from the desorption pipe; The rotating arc inclined roller was used for roller compaction. After the roller compaction, the waste pipe and the mandrel were separated. The inner diameter of the waste pipe was larger than the outer diameter of the mandrel by 1 mm to 3 mm.Step 6: Secondary heating, secondary heating in the secondary heating furnace, after the removal of the stick, the heating temperature is not less than 950 degrees, and the secondary heating furnace is heated with gas or electricity;Step 7: Sizing and shaping, passing the reheated waste pipe through the micro-strain reducing and sizing unit, reducing, sizing, shaping, and forming a hot finished pipe;Step 8: After cooling, the hot finished tube is cooled through a step cooling bed, and the finished product is collected. The cooled product tube is straightened, cut, tested, packaged, and tagged into a warehouse to form a commodity tube.

Small-diameter ultra-thin-wall seamless steel pipe hot-rolled technology, the use of six-stand mandrel with longitudinal rolling, the use of thick-walled pipe after perforation of high heat, wear thick rolling, to solve the small diameter seamless pipe after perforation The problem of inability to hot-roll at low temperatures is that the hot-rolling process is more efficient and less costly than the cold-drawning(milk) production process.

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