1. Manufacturing method: According to different production methods, it can be divided into hot rolled tube, cold rolled tube, cold drawn tube, extruded tube, etc.
a. Hot rolled seamless tubes are generally produced on automatic tube rolling units. After inspection and removal of surface defects, the solid tube billet is cut to the required length, centered on the perforated end face of the tube billet, and then sent to the heating furnace for heating and pierced on the piercer. While the piercing is continuously rotating and advancing, under the action of the roller and the plug, a cavity is gradually formed inside the tube blank, called a capillary tube. And then sent to the automatic tube rolling machine to continue rolling. Finally, the whole wall thickness is adjusted by the whole machine, and the diameter is determined by the sizing machine to meet the specifications. It is a more advanced method to produce hot-rolled seamless steel tubes using continuous tube rolling units.
b. If you want to obtain a seamless tube with smaller size and better quality, you must use cold rolling, cold drawing or a combination of the two. Cold rolling is usually carried out on a two-roll mill. The steel pipe is rolled in a circular pass composed of a variable-section round hole groove and a fixed conical head. Cold drawing is usually carried out on a single-chain or double-chain cold drawing machine of 0.5-100T.
c. The extrusion method is to put the heated tube blank in a closed extrusion cylinder. The perforated rod and the extrusion rod move together so that the extrusion is extruded from the smaller die hole. This method can produce steel pipes with smaller diameters. 2. Uses 2.1. Seamless pipes are widely used. The general-purpose seamless pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, with the largest output, and are mainly used as pipes or structural parts for conveying fluids.
2. Seamless steel pipe uses
a. Seamless pipes are widely used. The general-purpose seamless pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, with the largest output, and are mainly used as pipes or structural parts for conveying fluids.
b. According to different uses, there are three types of supply: a, supply according to chemical composition and mechanical properties; b, supply according to mechanical properties; c, supply according to hydraulic test. Steel pipes supplied in categories a and b, if used to withstand liquid pressure, are also subject to hydrostatic tests.
c. Widely used in the manufacture of structural parts and mechanical parts, such as petroleum drill pipes, automobile drive shafts, bicycle racks and steel scaffolds used in construction and construction of circular parts with steel pipes, which can improve material utilization, simplify manufacturing processes, save materials and processing Working hours have been widely manufactured with steel pipes. Special-purpose seamless pipes include boiler seamless pipes, geological seamless pipes and petroleum seamless pipes.