Precise control of the wall thickness and diameter of seamless pipes is the key to ensuring their quality and performance. In the production process, it is necessary to use a variety of technologies and methods to achieve precise control. Nansteel Manufacturing Co.,Ltd has carefully summarized the main methods for controlling the wall thickness and diameter of seamless steel pipes:
Factors affecting wall thickness and diameter
1. Tube quality: The size, shape, wall thickness uniformity, etc. of the tube directly affect the wall thickness and diameter of the final steel pipe.
2. Heating temperature and uniformity: Uneven heating temperature will lead to uneven deformation during piercing and rolling, which will affect the wall thickness and diameter.
3. Punching process and parameters: The adjustment of the piercer, the position and shape of the plug, the shape and parameters of the roller, etc. will affect the wall thickness and diameter of the rough tube.
4. Rolling process and parameters: Adjustment of the rolling mill, shape and parameters of the rolls, rolling speed, tension, etc. will affect the wall thickness and diameter of the steel pipe.
5. Sizing process and parameters: The adjustment of the sizing machine, the shape and parameters of the sizing rollers, etc. directly affect the final outer diameter of the steel pipe.
6. Cooling process: Cooling speed and uniformity will affect the dimensional changes of the steel pipe.
Methods for controlling wall thickness
1. Precise control of tube blanks
High-precision continuous casting or rolling technology is used to ensure the size and shape accuracy of the tube billet.
Strict inspection is carried out on the tube billet to eliminate unqualified tube billets.
2. Optimizing the heating process
Use advanced heating furnaces, such as ring heating furnaces, walking beam heating furnaces, etc. to ensure uniform heating of the tube billet.
Use precise temperature control systems to control the heating temperature within a reasonable range.
3. Precisely control the perforation process
Select the perforator and the punch properly and adjust them precisely.
Control various parameters in the perforation process, such as roll speed, feed speed, etc.
4. Use advanced rolling technology
Adopt advanced rolling mills, such as PQF continuous rolling mill, ACCU-Roll planetary rolling mill, etc., to improve rolling accuracy.
Adopt an automated control system to accurately control rolling parameters, such as roll spacing, rolling speed, tension, etc.
Use tension reduction technology to accurately control wall thickness by controlling tension. During tension reduction, the working diameter position of the roll and the steel pipe will change with the change of tension, thereby affecting the control of wall thickness.
5. Online wall thickness measurement
The online wall thickness measuring instrument is used to monitor the wall thickness of the steel pipe in real time, and the rolling parameters are adjusted according to the measurement results to achieve closed-loop control. The online wall thickness measuring instrument for seamless steel pipes can perform continuous multi-point scanning under high temperature conditions of the steel pipe.
Methods for controlling diameter
1. Precise control of tube blanks and piercing
The diameter of the tube blank and the rough tube diameter after piercing directly affect the diameter of the final steel pipe.
2. Precise control of the rolling process
The outer diameter of the steel pipe is controlled by adjusting the spacing and shape of the rollers.
3. Using sizing technology
Use a sizing mill or a stretch reducer to size the steel pipe and accurately control the final outer diameter of the steel pipe.
4. Online diameter measurement
An online diameter measuring instrument is used to monitor the diameter of the steel pipe in real time, and the rolling or sizing parameters are adjusted according to the measurement results.
Other auxiliary means
Heat treatment: Through reasonable heat treatment process, the dimensional changes of steel pipes during the cooling process can be reduced.
Accurate measuring tools and methods: Use high-precision measuring tools, such as vernier calipers, micrometers, etc., to accurately measure the size of the steel pipe and make adjustments based on the measurement results.
Quality Management System: Establish a sound quality management system to strictly monitor and manage the production process to ensure that all process parameters are within the control range.
Read more: Things to Note when Buying Thick-walled Seamless Steel Pipes
Factors affecting wall thickness and diameter
1. Tube quality: The size, shape, wall thickness uniformity, etc. of the tube directly affect the wall thickness and diameter of the final steel pipe.
2. Heating temperature and uniformity: Uneven heating temperature will lead to uneven deformation during piercing and rolling, which will affect the wall thickness and diameter.
3. Punching process and parameters: The adjustment of the piercer, the position and shape of the plug, the shape and parameters of the roller, etc. will affect the wall thickness and diameter of the rough tube.
4. Rolling process and parameters: Adjustment of the rolling mill, shape and parameters of the rolls, rolling speed, tension, etc. will affect the wall thickness and diameter of the steel pipe.
5. Sizing process and parameters: The adjustment of the sizing machine, the shape and parameters of the sizing rollers, etc. directly affect the final outer diameter of the steel pipe.
6. Cooling process: Cooling speed and uniformity will affect the dimensional changes of the steel pipe.
Methods for controlling wall thickness
1. Precise control of tube blanks
High-precision continuous casting or rolling technology is used to ensure the size and shape accuracy of the tube billet.
Strict inspection is carried out on the tube billet to eliminate unqualified tube billets.
2. Optimizing the heating process
Use advanced heating furnaces, such as ring heating furnaces, walking beam heating furnaces, etc. to ensure uniform heating of the tube billet.
Use precise temperature control systems to control the heating temperature within a reasonable range.
3. Precisely control the perforation process
Select the perforator and the punch properly and adjust them precisely.
Control various parameters in the perforation process, such as roll speed, feed speed, etc.
4. Use advanced rolling technology
Adopt advanced rolling mills, such as PQF continuous rolling mill, ACCU-Roll planetary rolling mill, etc., to improve rolling accuracy.
Adopt an automated control system to accurately control rolling parameters, such as roll spacing, rolling speed, tension, etc.
Use tension reduction technology to accurately control wall thickness by controlling tension. During tension reduction, the working diameter position of the roll and the steel pipe will change with the change of tension, thereby affecting the control of wall thickness.
5. Online wall thickness measurement
The online wall thickness measuring instrument is used to monitor the wall thickness of the steel pipe in real time, and the rolling parameters are adjusted according to the measurement results to achieve closed-loop control. The online wall thickness measuring instrument for seamless steel pipes can perform continuous multi-point scanning under high temperature conditions of the steel pipe.
Methods for controlling diameter
1. Precise control of tube blanks and piercing
The diameter of the tube blank and the rough tube diameter after piercing directly affect the diameter of the final steel pipe.
2. Precise control of the rolling process
The outer diameter of the steel pipe is controlled by adjusting the spacing and shape of the rollers.
3. Using sizing technology
Use a sizing mill or a stretch reducer to size the steel pipe and accurately control the final outer diameter of the steel pipe.
4. Online diameter measurement
An online diameter measuring instrument is used to monitor the diameter of the steel pipe in real time, and the rolling or sizing parameters are adjusted according to the measurement results.
Other auxiliary means
Heat treatment: Through reasonable heat treatment process, the dimensional changes of steel pipes during the cooling process can be reduced.
Accurate measuring tools and methods: Use high-precision measuring tools, such as vernier calipers, micrometers, etc., to accurately measure the size of the steel pipe and make adjustments based on the measurement results.
Quality Management System: Establish a sound quality management system to strictly monitor and manage the production process to ensure that all process parameters are within the control range.
Read more: Things to Note when Buying Thick-walled Seamless Steel Pipes
