Steel pipe No. 45 for the production of pipes

No. 45 steel pipe is made of steel ingot or solid tube billet perforated into capillary tube, and then made of hot rolled, cold rolled or cold drawn.

The raw material of rolling seamless tube is round tube blank, and the round tube embryo is cut by the cutting machine and the billet with the growth degree of about 1 meter, and is sent to the furnace by conveyor belt for heating. The billets are heated in a furnace at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is the key problem. After the round tube billet is released, it must be perforated by the pressure piercing machine. Generally, the most common piercing machine is the conical roll piercing machine, which has high production efficiency, good product quality, large perforating and expanding diameter, and can wear a variety of steel. After the perforation, the round tube blank is successively rolled by three roller skew, continuous rolling or extrusion. After extrusion, the tube should be removed for sizing. The sizing machine rotates into the steel embryo at high speed through the conical drill to punch holes and form the steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the caliper drill bit. After the steel pipe is calibrated, it enters the cooling tower and is cooled by water spray. After the steel pipe is cooled, it will be straightened. After the steel pipe is straightened, it is sent to the metal inspection machine (or hydraulic test) for internal inspection. If there are cracks, bubbles and other problems inside the steel pipe, it will be detected. After the steel pipe inspection, it is also strictly selected by hand. After the steel pipe quality inspection, paint the number, specification, production batch number, etc. And hoisted by crane into the warehouse.

Seamless steel pipes are divided into two categories: hot rolled and cold rolled (dial) seamless steel pipes.

Hot-rolled seamless steel pipe is divided into general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe, geological steel pipe and other steel pipes.

In addition to the general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe, other steel pipes, also includes carbon thin-wall steel pipe, alloy thin-wall steel pipe, stainless thin-wall steel pipe, special-shaped steel pipe. The outer diameter of the hot-rolled seamless pipe is generally greater than 32mm, the wall thickness is 2.5-75mm, the diameter of the cold-rolled seamless steel pipe can be up to 6mm, the wall thickness can be up to 0.25mm, the outer diameter of the thin-walled pipe can be up to 5mm, the wall thickness is less than 0.25mm, and the size accuracy is higher than that of the hot-rolled seamless pipe.

Generally used seamless steel pipe: is made of 10, 20, 30, 35, 45 and other high-quality carbon junction steel 16Mn, 5MnV and other low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloy steel hot rolled or cold rolled. Seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid transport pipelines. 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. Hot-rolled steel pipes are delivered in hot-rolled or heat-treated condition; Delivered cold rolled in heat-treated condition.

Seamless steel pipe for low and medium pressure boilers: used to manufacture all kinds of low and medium pressure boilers, superheated steam pipes, boiling water pipes, water wall pipes and superheated steam pipes for locomotive boilers, large smoke pipes, small smoke pipes and arch brick pipes. With high-quality carbon structural steel hot rolled or cold rolled (dial) seamless steel pipe. Mainly made of 10, 20 steel, in addition to ensuring chemical composition and mechanical properties to do hydraulic test, flange, flaring, flattening and other tests. Hot rolling in hot rolling condition, cold rolling (dial) in heat treatment condition delivery.

High pressure boiler steel pipe: It is mainly used to manufacture high-quality carbon structural steel, alloy structural steel and stainless heat-resistant steel seamless steel pipes for steam boiler pipes with high pressure and above pressure. These boiler tubes often work at high temperature and high pressure, and oxidation and corrosion occur under the action of high temperature flue gas and water steam, so the steel tubes are required to have high durable strength and high oxidation resistance. And has good organizational stability, the use of steel numbers are: high-quality carbon structural steel numbers 20G, 20MnG, 25MnG; Alloy structural steel No. 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, 12Cr3MoVSiTiB, etc. Rust heat-resistant steel commonly used 1Cr18Ni9, 1Cr18Ni11Nb high-pressure boiler tubes in addition to ensuring chemical composition and mechanical properties, to do hydraulic test one by one, to do flaring, flattening test. Steel pipes are delivered in heat-treated condition. In addition, there are also certain requirements for the microstructure, grain size and decarburization layer of the finished steel pipe.

Seamless steel pipe for geological drilling and oil drilling: To explore the structure of underground rock formations, groundwater, oil, natural gas and mineral resources, the use of drilling RIGS. Oil and natural gas mining is inseparable from drilling, seamless steel pipe for oil drilling is the main equipment for drilling, mainly including core outer pipe, core inner pipe, casing, drill pipe and so on. Because the drilling pipe has to go deep into the depth of several thousand meters, the working conditions are extremely complex, the drill pipe is subjected to stress such as tension, pressure, bending, torsion and unbalanced impact load, but also by mud, rock wear, therefore, the pipe must have sufficient strength, hardness, wear resistance and impact toughness. Steel pipe with "DZ" (geological Chinese pinyin prefix) plus a number to represent the steel yield point, the commonly used steel number DZ45 45MnB, 50Mn; 40Mn2, 40Mn2Si of DZ50; DZ55 40Mn2Mo, 40MnVB; 40MnMoB of DZ60, 27MnMoVB of DZ65. Steel pipes are delivered in heat-treated condition.

Petroleum cracking pipe: Seamless pipe for furnace tubes, heat exchanger tubes and pipelines used in petroleum refineries. Commonly used high-quality carbon steel (10, 20), alloy steel (12CrMo, 15CrMo), heat-resistant steel (12Cr2Mo, 15Cr5Mo), stainless steel (1Cr18Ni9, 1Cr18Ni9Ti) manufacturing. In addition to the chemical composition and various mechanical properties of the steel pipe, it is necessary to ensure water pressure, flattening, flaring and other tests, as well as surface quality and non-destructive inspection. Steel pipes are delivered under heat treatment. Stainless steel pipe: with a variety of stainless steel hot rolled, cold rolled stainless steel pipe, widely used in petroleum, chemical equipment pipelines and various uses of stainless steel structural parts, in addition to ensure chemical composition and mechanical properties, where used to withstand fluid pressure to ensure that the hydraulic test qualified. All kinds of special steel pipes should be guaranteed according to the specified conditions.