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Brief Introduction of Hot Rolled Seamless Pipes
Oct 28, 2021
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As the name suggests, the hot rolled seamless pipe refers to the seamless pipe made of high-quality carbon structural steel or solid tube blank such as No. 10, No. 20, No. 30 and No. 35 through hot rolling process and perforation. Due to the good sealing, high strength and strong pressure resistance, it is generally used for fluid transportation. Due to the high temperature during processing, the hot-rolled seamless pipe has large deformation, which can bear large deformation pressure. It has relatively low requirements for dimensional accuracy, which can effectively avoid the flatness problem.
The hot rolled seamless pipe is relative to the cold rolling one. The cold rolling is rolled below the recrystallization temperature. It is rolled above the recrystallization temperature. According to different usage and materials, the hot-rolled seamless pipe can be divided into many kinds of pipes, such as alloy pipes, which is mainly used in petroleum, smelting, chemical industry and other fields. The high-pressure boiler tube, which is mainly used for heating pipes, steam pipes and other high-pressure boilers. The high-pressure fertilizer pipe, which is used in ultra-low temperature (- 40°C) or ultra-high temperature (400 °C) working environment and high-pressure environment.
Preparation of hot rolled seamless pipes
General seamless steel pipes: it is made of 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 alloy steel by hot rolling or cold rolling. The seamless pipe made of 10, 20 and other low carbon steel is mainly used for fluid transmission pipeline. Seamless pipes made of medium carbon steel such as 45 and 40Cr are used to manufacture mechanical parts, such as stressed parts of automobiles and tractors. Generally, the strength and flattening test of seamless steel pipes should be ensured. Hot rolled steel pipes should be delivered in hot rolling or heat treatment state. The cold rolled steel pipe should be delivered in heat treatment state.
1. Hot rolling (extrusion of seamless steel pipes): round billet → heating → piercing → three roll cross rolling, continuous rolling or extrusion → pipe stripping → sizing (or reducing) → cooling → straightening → hydrostatic test (or flaw detection) → marking → warehousing
2. Cold drawn (rolling) seamless steel pipes: round billet → heating → piercing → heading → annealing → pickling → oiling (copper plating) → billet → heat treatment → straightening → hydrostatic test (flaw detection) → marking → warehousing
Calculation formula
(Outer diameter wall thickness) * Wall thickness * 0.02466 = kg / M (weight per M)
Summary: the hot rolled seamless pipe is mostly used for fluid transportation in large-scale construction process, which is conducive to the transportation of oil smelters, geological exploration, gas hydraulics, corrosive materials, etc. Therefore, the quality requirements for the pipe are very high. The material is required to have high corrosion resistance and compression resistance, and the production process needs to be accurate, strictly seamless, to prevent the transportation flow and the quality of the leak. Because there are many categories of hot rolled seamless pipes, users need to choose the most suitable pipe according to their actual construction needs.
The hot rolled seamless pipe is relative to the cold rolling one. The cold rolling is rolled below the recrystallization temperature. It is rolled above the recrystallization temperature. According to different usage and materials, the hot-rolled seamless pipe can be divided into many kinds of pipes, such as alloy pipes, which is mainly used in petroleum, smelting, chemical industry and other fields. The high-pressure boiler tube, which is mainly used for heating pipes, steam pipes and other high-pressure boilers. The high-pressure fertilizer pipe, which is used in ultra-low temperature (- 40°C) or ultra-high temperature (400 °C) working environment and high-pressure environment.
Preparation of hot rolled seamless pipes
General seamless steel pipes: it is made of 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 alloy steel by hot rolling or cold rolling. The seamless pipe made of 10, 20 and other low carbon steel is mainly used for fluid transmission pipeline. Seamless pipes made of medium carbon steel such as 45 and 40Cr are used to manufacture mechanical parts, such as stressed parts of automobiles and tractors. Generally, the strength and flattening test of seamless steel pipes should be ensured. Hot rolled steel pipes should be delivered in hot rolling or heat treatment state. The cold rolled steel pipe should be delivered in heat treatment state.
1. Hot rolling (extrusion of seamless steel pipes): round billet → heating → piercing → three roll cross rolling, continuous rolling or extrusion → pipe stripping → sizing (or reducing) → cooling → straightening → hydrostatic test (or flaw detection) → marking → warehousing
2. Cold drawn (rolling) seamless steel pipes: round billet → heating → piercing → heading → annealing → pickling → oiling (copper plating) → billet → heat treatment → straightening → hydrostatic test (flaw detection) → marking → warehousing
Calculation formula
(Outer diameter wall thickness) * Wall thickness * 0.02466 = kg / M (weight per M)
Summary: the hot rolled seamless pipe is mostly used for fluid transportation in large-scale construction process, which is conducive to the transportation of oil smelters, geological exploration, gas hydraulics, corrosive materials, etc. Therefore, the quality requirements for the pipe are very high. The material is required to have high corrosion resistance and compression resistance, and the production process needs to be accurate, strictly seamless, to prevent the transportation flow and the quality of the leak. Because there are many categories of hot rolled seamless pipes, users need to choose the most suitable pipe according to their actual construction needs.
