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Features And Manufacturing Process of Large Diameter SMLS Pipes
Sep 14, 2021
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Brief Introduction of Large Diameter Seamless Steel Pipes
The large diameter seamless steel pipe has a hollow section, which can transport a large number of fluid, such as the transportation of oil, natural gas, gas, water and some solid materials pipelines. Compared with round steel and other solid steel, the steel pipe has a smaller diameter. If the bending and torsion strength are same, the weight is lighter. It is a kind of economic steel section. The large diameter seamless steel pipe is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile drive shafts, bicycle frames and steel scaffoldings used in construction with manufacturing ring parts of steel pipes. It can improve the material utilization rate, simplify the manufacturing process, save material and processing hours. It has been widely used in the manufacture of steel pipes.
Features of large diameter seamless steel pipes:
1. Smaller diameter
2. High precision and it can be made in a small batch.
3. Cold-drawn products have high precision and good surface quality.
4. The transverse area of steel pipes is more complex.
5. The performance of steel pipes is better, and the metal is denser.
DATANG STEEL PIPE CO., LTD owns advanced technology equipment and complete detection means. With advanced testing equipment, we have established a sound assurance system of quality and passed the ISO9001:2015 international quality system certification. The products are widely used in oil pipeline, natural gas pipeline, urban heating pipeline, water supply pipeline, electric power and other anti-corrosion projects. We have participated in the anti-corrosion and insulation projects of many long-distance oil, gas and water pipelines exported to Indonesia, Sudan, Saudi Arabia and South Africa. Our product quality and service have been well received by our customers.
Calculation methods of large diameter seamless steel pipes
A: known outer diameter specification and wall thickness calculation methods of large diameter seamless steel pipes for bearing pressure (Different materials of tensile strength of steel pipes are different.)
Pressure = (wall thickness *2* tensile strength of materials of steel pipes) / (outer diameter * coefficient)
B: known outside diameter and pressure calculation method of large diameter seamless steel pipes for wall thickness:
Wall thickness = (pressure * outer diameter * coefficient) / (2* tensile strength of materials of steel pipes)
The manufacturing process of large diameter seamless steel pipes:
1. Hot rolling (extruded seamless steel pipes): the billet of round pipes → heating → perforation → three-high cross rolling, continuous rolling or extrusion → pipe removal → sizing (or reducing)→ cooling → straightening → hydraulic test (or inspection)→ marking → storage
2. Cold-drawn (rolled) seamless steel pipes: the billet of round pipes → heating → perforation → head → annealing → pickling → oiling (copper plating)→ multi-pass cold drawing (cold rolling)→ billet pipes → heat treatment → straightening → hydraulic test (flaw detection)→ marking → warehouse billet is sent into the furnace to be heated
The temperature is about 1200℃. The temperature control in the furnace is the key problem. After the billet of round pipes is released, it must be perforated by pressure punch. Generally, the more common punching machine is the conical roll punching machine. This kind of punching machine production efficiency is high. The product quality is good. The perforation expanding diameter is large, which can wear a variety of steels.
After the perforation, the billet of round pipes is successively cross-rolled, tandem rolled or extruded by three rollers. Remove the tube and size after extrusion. The caliper is drilled into the steel embryo through high-speed rotating cone bit to form the steel pipe. The inside diameter of the steel pipe is determined by the outside diameter length of the bit of the caliper. After the diameter of the steel pipe, it enters the cooling tower and is cooled by water spray. After cooling, the steel pipe will be straightened. After straightening, the steel pipe is sent by the conveyor belt to the metal flaw detector (or hydraulic test) for internal flaw detection.
If there are cracks, bubbles and other problems inside the steel pipe, it will be detected. The quality of steel pipes should be chosen after the strict manual selection. After quality inspection, the number, specification, production batch number and other items should be sprayed with paint and then it will be lifted into the warehouse by a crane. The application of a large diameter seamless steel pipe is wide.
a. Seamless steel pipes for general purposes are rolled by ordinary carbon structural steel, low alloy structural steel or alloy structural steel, and the output is large. They are mainly used as pipelines or structural parts for conveying fluids.
b. Supply in three ways according to the usage:
A. Supply according to chemical components and mechanical properties
B. Supply according to mechanical properties
C. Supply according to hydraulic test
As for steel pipes supplied under A and B, if it is used to withstand liquid pressure, it should also be hydro-tested.
c. Special purposes of seamless pipes: boiler seamless pipes, chemical power and geological seamless steel pipes and petroleum seamless pipes and other kinds.
The large diameter seamless steel pipe has a hollow section, which can transport a large number of fluid, such as the transportation of oil, natural gas, gas, water and some solid materials pipelines. Compared with round steel and other solid steel, the steel pipe has a smaller diameter. If the bending and torsion strength are same, the weight is lighter. It is a kind of economic steel section. The large diameter seamless steel pipe is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile drive shafts, bicycle frames and steel scaffoldings used in construction with manufacturing ring parts of steel pipes. It can improve the material utilization rate, simplify the manufacturing process, save material and processing hours. It has been widely used in the manufacture of steel pipes.
Features of large diameter seamless steel pipes:
1. Smaller diameter
2. High precision and it can be made in a small batch.
3. Cold-drawn products have high precision and good surface quality.
4. The transverse area of steel pipes is more complex.
5. The performance of steel pipes is better, and the metal is denser.
DATANG STEEL PIPE CO., LTD owns advanced technology equipment and complete detection means. With advanced testing equipment, we have established a sound assurance system of quality and passed the ISO9001:2015 international quality system certification. The products are widely used in oil pipeline, natural gas pipeline, urban heating pipeline, water supply pipeline, electric power and other anti-corrosion projects. We have participated in the anti-corrosion and insulation projects of many long-distance oil, gas and water pipelines exported to Indonesia, Sudan, Saudi Arabia and South Africa. Our product quality and service have been well received by our customers.
Calculation methods of large diameter seamless steel pipes
A: known outer diameter specification and wall thickness calculation methods of large diameter seamless steel pipes for bearing pressure (Different materials of tensile strength of steel pipes are different.)
Pressure = (wall thickness *2* tensile strength of materials of steel pipes) / (outer diameter * coefficient)
B: known outside diameter and pressure calculation method of large diameter seamless steel pipes for wall thickness:
Wall thickness = (pressure * outer diameter * coefficient) / (2* tensile strength of materials of steel pipes)
The manufacturing process of large diameter seamless steel pipes:
1. Hot rolling (extruded seamless steel pipes): the billet of round pipes → heating → perforation → three-high cross rolling, continuous rolling or extrusion → pipe removal → sizing (or reducing)→ cooling → straightening → hydraulic test (or inspection)→ marking → storage
2. Cold-drawn (rolled) seamless steel pipes: the billet of round pipes → heating → perforation → head → annealing → pickling → oiling (copper plating)→ multi-pass cold drawing (cold rolling)→ billet pipes → heat treatment → straightening → hydraulic test (flaw detection)→ marking → warehouse billet is sent into the furnace to be heated
The temperature is about 1200℃. The temperature control in the furnace is the key problem. After the billet of round pipes is released, it must be perforated by pressure punch. Generally, the more common punching machine is the conical roll punching machine. This kind of punching machine production efficiency is high. The product quality is good. The perforation expanding diameter is large, which can wear a variety of steels.
After the perforation, the billet of round pipes is successively cross-rolled, tandem rolled or extruded by three rollers. Remove the tube and size after extrusion. The caliper is drilled into the steel embryo through high-speed rotating cone bit to form the steel pipe. The inside diameter of the steel pipe is determined by the outside diameter length of the bit of the caliper. After the diameter of the steel pipe, it enters the cooling tower and is cooled by water spray. After cooling, the steel pipe will be straightened. After straightening, the steel pipe is sent by the conveyor belt to the metal flaw detector (or hydraulic test) for internal flaw detection.
If there are cracks, bubbles and other problems inside the steel pipe, it will be detected. The quality of steel pipes should be chosen after the strict manual selection. After quality inspection, the number, specification, production batch number and other items should be sprayed with paint and then it will be lifted into the warehouse by a crane. The application of a large diameter seamless steel pipe is wide.
a. Seamless steel pipes for general purposes are rolled by ordinary carbon structural steel, low alloy structural steel or alloy structural steel, and the output is large. They are mainly used as pipelines or structural parts for conveying fluids.
b. Supply in three ways according to the usage:
A. Supply according to chemical components and mechanical properties
B. Supply according to mechanical properties
C. Supply according to hydraulic test
As for steel pipes supplied under A and B, if it is used to withstand liquid pressure, it should also be hydro-tested.
c. Special purposes of seamless pipes: boiler seamless pipes, chemical power and geological seamless steel pipes and petroleum seamless pipes and other kinds.
