① hot-rolled seamless steel pipe main production process (△ main inspection process):

Tube blank preparation and inspection △ → tube heating → perforation → rolling → steel pipe reheating → set (minus) diameter → heat treatment △ → finished pipe straightening → finishing → inspection △ (lossless, physical and chemical, Taiwan inspection) → storage

② cold-rolled (pull) seamless steel pipe main production process:

Ingredients → Pickling Lubrication → Cold Rolling → Heat Treatment → Straightening → Finishing → Inspection

General seamless steel pipe production process can be divided into cold drawing and hot rolling two, cold-rolled seamless steel pipe production process is generally more complicated than hot-rolled, tube first to be three-roll rolling, after extrusion to be carried out Sizing test, if the surface is not responding to the crack after the tube to go through the cutting machine for cutting, cutting into a length of about one meter of the blank. And then into the annealing process, the use of acidic acid for acid pickling, pickling should pay attention to whether the surface of a large number of foaming produce, if there is a large number of blistering that the quality of steel pipe can not meet the corresponding standards. The appearance of cold-rolled seamless steel pipe is shorter than hot-rolled seamless steel pipe, cold-rolled seamless steel pipe wall thickness is generally smaller than the hot-rolled seamless steel pipe, but the surface looks thicker than thick-walled seamless steel pipe, the surface is not too More rough, caliber no too much burr.

Hot-rolled seamless steel pipe delivery status is generally hot-rolled state after heat treatment for delivery. Hot-rolled seamless steel pipe after the quality inspection to go through the rigorous manual selection of workers, after the quality inspection to the surface of the oil, and then followed by a number of cold drawing experiments, hot rolling after the perforation of the experiment , If the perforation is too large to be straightening correction. In the straightening and then sent by the transmission device to the flaw detector for testing, and finally labeled, the specifications arranged after the placement into the warehouse.

Round pipe → heating → perforation → three roll skew rolling, continuous rolling or extrusion → off pipe → sizing (or reducing diameter) → cooling → straightening → water pressure test (or flaw detection) → mark → storage seamless steel pipe Is made of steel ingot or solid tube through the perforated tube, and then by hot rolling, cold or cold made. The specifications of the seamless steel pipe are indicated by the outer diameter * wall thickness mm.

Hot-rolled seamless tube diameter is generally greater than 32mm, wall thickness of 2.5-200mm, cold-rolled seamless steel pipe diameter to 6mm, wall thickness to 0.25mm, thin tube diameter to 5mm wall thickness of less than 0.25mm, cold Rolling ratio is higher than that of hot rolling.

General use of seamless steel pipe is 10,20,30,35,45 and other high-quality carbon steel 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other synthetic steel made of hot-rolled or cold-rolled. 10,20 and other low-carbon steel seamless pipe is mainly used for fluid pipeline. 45,40Cr and other carbon steel made of seamless pipe used to manufacture mechanical parts, such as cars, tractors force parts. General use of seamless steel pipe to ensure strength and flattening test. The hot-rolled steel pipe is delivered in a hot-rolled state or a heat-treated state; cold rolling is delivered in a heat-treated state.

Hot rolling, as the name suggests, the rolling of the high temperature, so the deformation resistance is small, you can achieve a large amount of deformation. Rolling steel as an example, the general continuous casting slab thickness of about 230mm, and after rough rolling and finishing, the final thickness of 1 ~ 20mm. At the same time, due to the width of the steel plate is small, the size of the precision requirements are relatively low, not prone to plate-shaped problem to dominate the convex. For the organization requirements, generally through the control of rolling control to achieve, that is, control the rolling of the rolling temperature, finishing temperature. Round tube → heating → perforation → start → annealing → pickling → oil (copper) → Multi-pass cold drawing (cold rolling) → billet → heat treatment → straightening → water pressure test (flaw detection) → mark → storage.