Seamless carbon steel pipe is a rough tube made by perforating a steel ingot or solid tube billet. It is a seamless steel pipe, and then a steel pipe made by hot rolling, cold rolling or cold drawing. This kind of steel pipe is widely used in construction, petroleum, chemical industry, machinery and other fields due to its seamless characteristics, high strength, good corrosion resistance and good weldability. This kind of steel pipe is not only used for pipeline transportation, but also widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile drive shafts, bicycle frames, and steel scaffolding in construction. Although there are many types of seamless carbon steel pipes, they all have some common key characteristics, such as strength, hardness and durability. This article will introduce the manufacturing process, classification, application fields and characteristics of seamless carbon steel pipes in detail.
Manufacturing process of seamless carbon steel pipe
Raw material preparation
The raw material of seamless carbon steel pipe is round tube billet. The round tube billet is first cut by a cutting machine into a billet with a length of about 1 meter. The billet is then sent to the furnace by a conveyor belt for heating. The heating temperature is usually around 1200 degrees Celsius. The fuel can be hydrogen or acetylene. Accurate control of the temperature in the furnace is a crucial part of the production process.
Piercing and rolling
The heated round tube billet is perforated by a pressure perforator. The most common perforating equipment is the tapered roller perforator, which has high production efficiency and good product quality and is suitable for perforating a variety of steel grades. After the perforation is completed, the round tube billet is successively subjected to three-roller oblique rolling, continuous rolling or extrusion processes. After extrusion, the tube billet enters the sizing machine for sizing. The sizing machine uses a tapered drill to rotate at high speed into the steel billet to punch holes to form the final steel pipe shape. The inner diameter of the steel pipe is determined by the outer diameter length of the drill bit of the sizing machine.
Cooling and straightening
The sizing steel pipe enters the cooling tower and is cooled by water spraying. After cooling, the steel pipe needs to go through a straightening process to ensure that its straightness meets the standard. The straightened steel pipe is sent to the metal flaw detector or water pressure test equipment by a conveyor belt for internal flaw detection to detect whether there are cracks, bubbles and other problems inside. The steel pipes that have passed strict quality inspection are then manually selected and finally hoisted into the warehouse by a crane.
Classification of seamless carbon steel pipes
Seamless carbon steel pipes can be divided into hot-rolled and cold-rolled (drawn) according to different manufacturing processes and uses.
Hot-rolled seamless steel pipes
Hot-rolled seamless steel pipes usually have an outer diameter greater than 32 mm and a wall thickness between 2.5 and 75 mm. This type of steel pipe is delivered in a hot-rolled state or after heat treatment. It is mainly used to manufacture mechanical parts, fluid delivery pipelines, etc. The materials used are mostly high-quality carbon steels such as 10, 20, 30, 35, 45, etc., and there are also low-alloy structural steels such as 16Mn, 5MnV, etc., and alloy steels such as 40Cr, 30CrMnSi, 45Mn2, 40MnB, etc.
Cold-rolled (drawn) seamless steel pipes
The outer diameter of cold-rolled seamless steel pipes can be as small as 6 mm, and the wall thickness can be as thin as 0.25 mm. The outer diameter of thin-walled pipes can reach 5 mm, and the wall thickness is less than 0.25 mm. The dimensional accuracy of this type of steel pipe is higher than that of hot-rolled steel pipes, and it is delivered in a heat-treated state. Cold-rolled seamless steel pipes include general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, etc., as well as carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless thin-walled steel pipes and special-shaped steel pipes.
Application fields of seamless carbon steel pipes
Fluid transport pipelines
Seamless carbon steel pipes made of low carbon steels such as 10 and 20 are mainly used for fluid transport pipelines. Such pipes need to have good corrosion resistance and sufficient strength to ensure that they will not leak or break during long-term use.
Manufacturing of mechanical parts
Seamless pipes made of medium carbon steels such as 45 and 40Cr are mainly used to manufacture mechanical parts, such as stress-bearing parts of automobiles and tractors. These parts are subjected to complex stresses during operation, so the materials are required to have high strength and good mechanical properties.
Boiler pipes
Seamless steel pipes for low and medium pressure boilers are used to manufacture various low and medium pressure boilers, superheated steam pipes, boiling water pipes, water-cooled wall pipes, and superheated steam pipes for locomotive boilers, large smoke pipes, small smoke pipes, and arched brick pipes. These pipes are subjected to high temperature and high pressure during operation, requiring the steel pipes to have high lasting strength, high oxidation resistance, and good organizational stability.
Geological Drilling and Oil Drilling Control
Seamless steel pipes for geological drilling and oil drilling control are the main equipment for drilling, mainly including core outer pipes, core inner pipes, casing, drill pipes, etc. These pipes need to work under extremely complex geological conditions, requiring the material to have sufficient strength, hardness, wear resistance and impact toughness.
Petroleum Cracking Pipes
Petroleum cracking pipes are used for furnace pipes, heat exchanger pipes and seamless pipes in oil refineries, and are usually made of high-quality carbon steel, alloy steel and stainless steel. This type of pipe works under high temperature and high pressure and needs to have high heat resistance and corrosion resistance.
Stainless steel pipes
Stainless steel pipes are made of hot-rolled or cold-rolled stainless steels and are widely used in pipelines of petroleum and chemical equipment and stainless steel structural parts for various purposes. This type of pipe needs to have excellent corrosion resistance and mechanical properties. All steel pipes used to withstand fluid pressure must also pass water pressure tests.
Characteristics of seamless carbon steel pipes
Seamless carbon steel pipes have many excellent characteristics, which make them widely used in various industries. These characteristics include:
High strength
Seamless carbon steel pipes have high strength through strict manufacturing processes and material selection. This enables them to withstand complex stresses and remain stable under harsh conditions such as high pressure and high temperature.
Good corrosion resistance
Carbon steel materials themselves have good corrosion resistance. After proper anti-corrosion treatment, seamless carbon steel pipes can be used for a long time in harsh environments without corrosion and damage.
Excellent weldability
Seamless carbon steel pipes have good weldability, which makes it easy to perform welding operations during installation, ensuring the integrity and reliability of the pipeline system.
Precise dimensional control
Cold-rolled (pulled) seamless carbon steel pipes have high-precision dimensional control, which makes them perform well in application scenarios that require high precision. For example, when manufacturing precision mechanical parts, high-precision seamless carbon steel pipes can ensure that the size of the parts meets the design requirements.
Wide range of applications
Seamless carbon steel pipes are widely used in various fields such as construction, petroleum, chemical industry, and machinery due to their excellent characteristics. From fluid delivery pipelines to mechanical parts, from boiler pipes to geological drilling, seamless carbon steel pipes can meet almost all application requirements that require high strength and high durability.
Conclusion
As an important industrial material, seamless carbon steel pipes are widely used in various fields due to their high strength, good corrosion resistance and excellent weldability. Whether in the fields of construction, petroleum, chemical industry or machinery manufacturing, seamless carbon steel pipes play an irreplaceable role. Its fine manufacturing process and strict quality control ensure its excellent performance under various complex conditions. With the continuous advancement of technology, the application scope and performance of seamless carbon steel pipes will continue to expand and improve, providing more reliable material support for the development of various industries.
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