As an important basic material in the industrial field, seamless tubes are widely used in many industries such as petroleum, chemical industry, electric power, and machinery manufacturing. Precise control of the wall thickness and diameter of seamless tubes 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. The main methods of controlling the wall thickness and diameter of seamless steel tubes are carefully summarized:
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.
Conclusion
The precise control of the wall thickness and diameter of seamless tubes is a comprehensive process, which requires control of each link from tube blank preparation, heating, piercing, rolling, sizing, cooling, etc., and the use of advanced production technology, equipment and control systems, combined with precise measurement and quality management, can effectively ensure the dimensional accuracy and quality of seamless tubes. By comprehensively applying the above methods, the wall thickness and diameter of seamless tubes can be effectively controlled to meet various application requirements.
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