How to make seamless steel pipe?

1. Main production process of hot-rolled seamless steel pipe (△ Main inspection process) :

Preparation and inspection of tube blank △ heating of tube blank → perforation → Rolling pipe → reheating of steel pipe → fixing (reducing) diameter → heat treatment △ straightening of finished pipe → finishing → inspection △ (non-destructive, physical and chemical, table inspection) → storage

2, cold rolled (drawing) seamless steel pipe main production process:

Blank preparation → pickling lubrication → cold rolling (drawing) → heat treatment → straightening → finishing → inspection

The general production process of seamless steel pipe can be divided into cold drawing and hot rolling. The production process of cold rolled seamless steel pipe is generally more complex than that of hot rolling. The tube billet should first be rolled by three rolls, and the sizing test should be carried out after extrusion. Then enter the annealing process, annealing to acid liquid pickling, pickling should pay attention to whether there is a large number of bubbles on the surface, if there is a large number of bubbles that indicate the quality of the steel pipe can not reach the corresponding standard. The appearance of cold-rolled seamless steel pipe is shorter than that of hot-rolled seamless steel pipe. The wall thickness of cold-rolled seamless steel pipe is generally smaller than that of hot-rolled seamless steel pipe, but the surface looks brighter than that of thick-walled seamless steel pipe. The surface is not too rough and the diameter is not too much burr.

The delivery state of hot rolled seamless steel pipe is generally hot rolled state after heat treatment for delivery. Hot rolled seamless steel pipe after the quality inspection to the staff's strict manual selection, after the quality inspection to the surface of the oil, and then followed by many cold drawing experiment, hot rolling treatment to perforation experiment, if the perforation enlargement is too large to be straightening. After straightening, it is sent to the flaw detection machine by the transmission device for detection experiment. Finally, it is labeled, formatted and placed in the warehouse.

Round tube blank → heating → perforation → three-high diagonal rolling, continuous rolling or extrusion → stripping → sizing (or reducing) → cooling → straightening → hydrostatic test (or inspection) → marking → Seamless steel pipe into storage is made of steel ingot or solid tube blank perforated into wool tube, and then made by hot rolling, cold rolling or cold drawing. The specification of seamless steel pipe is expressed by the outer diameter * the thickness of the wall in millimeters.

The outer diameter of the hot-rolled seamless pipe is generally greater than 32mm, and the wall thickness is 2.5-200mm. The outer diameter of the cold-rolled seamless steel pipe can be up to 6mm, the wall thickness can be up to 0.25mm, and the outer diameter of the thin-walled pipe can be up to 5mm, and the wall thickness is less than 0.25mm.

Generally used seamless steel pipe is made of 10, 20, 30, 35, 45 and other high-quality carbon bonded steel 16Mn, 5MnV and other low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other combined steel hot rolled or cold rolled. 10, 20 low carbon steel manufacturing seamless pipe is mainly used for fluid conveying pipe. 45, 40Cr and other medium carbon steel seamless pipe to manufacture mechanical parts, such as cars, tractor parts. Generally use seamless steel pipe to ensure the strength and flattening test. Delivery of hot-rolled steel pipes in hot-rolled or heat-treated condition; Cold rolled and delivered in heat-treated condition.

Hot rolling, as the name implies, the temperature of the rolling parts is high, so the deformation resistance is small, can achieve a large amount of deformation. Taking the rolling of steel plate as an example, the general thickness of continuous casting billet is about 230mm, and after rough rolling and finishing rolling, the final thickness is 1~20mm. At the same time, due to the small thickness ratio of steel plate, dimensional accuracy requirements are relatively low, it is not easy to appear plate shape problems, to control the convexity. For the organization of the requirements, generally through the control of rolling control cold to achieve, that is, to control the finishing rolling temperature of the opening and final rolling temperature. Round tube blank → heating → perforating → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → Blank tube → Heat treatment → straightening → hydrostatic test (inspection) → marking → storage.