Hot-expanded seamless pipe – Summary of Core Process Links
Summary of Core Process Links
The seven core links of the Guanzhong medium and high frequency heat-expanded seamless steel pipe process—raw material inspection, mother pipe pretreatment, induction heating, expansion forming, cooling, finishing and finished product inspection—are closely connected and mutually restrictive, and each link is an indispensable part of ensuring product quality. Raw material inspection is the foundation, which blocks unqualified mother pipes from the source and avoids subsequent quality hidden dangers; mother pipe pretreatment provides a clean and standardized raw material foundation for induction heating and expansion forming, ensuring the effect of subsequent links; induction heating is the core, which determines the plastic state of the mother pipe and lays the foundation for smooth expansion forming; expansion forming is the key forming link, which directly determines the dimensional accuracy and shape quality of the finished pipe; cooling stabilizes the metal structure of the finished pipe and improves its mechanical properties, avoiding deformation and cracks; finishing improves the surface quality and dimensional accuracy of the finished pipe, enhancing its market competitiveness; finished product inspection is the last line of defense, which screens out unqualified products and ensures that qualified products flow into the market.
During the internship, I deeply realized that there is no trivial link in the production process. A small mistake in any link may lead to product scrapping and economic losses, such as the unqualified finished pipe caused by incomplete degreasing of the mother pipe, the crack of the mother pipe caused by excessive expansion ratio, and the scratch of the finished pipe caused by improper polishing pressure. These incidents let me understand that the control of process links must be strict, standardized and meticulous, and each parameter and each operation must comply with the process requirements. Only by controlling each core link in place can we stably produce high-quality Guanzhong medium and high frequency heat-expanded seamless steel pipes.
Summary of Intermediate Frequency and High Frequency Heat Expansion Process Comparison
As the two main forms of the Guanzhong medium and high frequency heat expansion process, intermediate frequency and high frequency heat expansion have their own advantages, disadvantages and applicable scenarios, and they complement each other to form a complete process system, which can meet the production needs of different specifications, different materials and different application fields of seamless steel pipes. The intermediate frequency heat expansion process has the advantages of deep heating depth, uniform temperature, strong production flexibility, and can produce large-diameter and thick-walled finished pipes. It is suitable for large-diameter transmission pipelines in petroleum chemical industry, municipal pipe network and other fields, but it has the shortcomings of high energy consumption and general surface quality; the high frequency heat expansion process has the advantages of fast heating speed, low energy consumption, high dimensional accuracy of finished pipes and good surface quality. It is suitable for small-diameter precision pipelines in precision machinery, medical equipment and other fields, but it cannot produce large-diameter and thick-walled finished pipes.
With the continuous upgrading of technology, the boundary between the two processes is gradually blurring. Through the optimization of induction coil structure, the improvement of heating method and the upgrading of equipment power, the intermediate frequency heat expansion process has improved the surface quality and reduced energy consumption, and the high frequency heat expansion process has increased the heating depth and expanded the product specification range. This trend of technological integration not only enriches the product types of the Guanzhong medium and high frequency heat expansion process, but also improves the overall technical level of the process. In actual production, enterprises should reasonably select the appropriate heat expansion process according to market demand, product specifications and customer requirements, so as to give full play to the advantages of the process, reduce production costs and improve production efficiency.
Summary of Internship Gains and Existing Problems
Through the internship in the Guanzhong medium and high frequency heat-expanded seamless steel pipe enterprise, I have achieved rich gains in professional knowledge, practical skills and ideological understanding. In terms of professional knowledge, I have systematically mastered the core principle, technical characteristics, key process control points and development status of the Guanzhong medium and high frequency heat expansion process, clarified the differences between the heat expansion process and the traditional hot-rolled process, and understood the application scenarios of different specifications of finished pipes; in terms of practical skills, I have participated in all seven core production links, mastered the basic operation methods of raw material inspection, polishing, induction heating parameter adjustment, finished product inspection and other links, and accumulated valuable practical experience; in terms of ideological understanding, I have realized the importance of strict compliance with process requirements, the responsibility of quality control, and the spirit of rigorous and pragmatic work.
At the same time, I also found some existing problems in the process during the internship. On the one hand, there is a large gap in the technical level between different enterprises. Some small and medium-sized enterprises still use traditional production equipment and processes, with uneven product quality, high energy consumption and serious pollutant emissions, facing the risk of being eliminated; on the other hand, some key technologies of the process still have room for improvement, such as the control of oxide scale generation during induction heating, the improvement of expansion ratio of high-strength steel mother pipes, and the further reduction of energy consumption. In addition, I also found my own shortcomings: my mastery of process parameter adjustment is not proficient enough, and my ability to solve sudden problems in production is insufficient, which needs to be improved through further study and practice.
Overall Summary of the Process
The Guanzhong medium and high frequency heat-expanded seamless steel pipe process is a local characteristic secondary thermal processing technology formed by long-term practice and improvement in Guanzhong region of Shaanxi Province. It has the advantages of low equipment investment, short production cycle, high production flexibility, and can produce large-diameter and medium-thin-walled seamless steel pipes. It has filled the gap of China’s large-diameter seamless steel pipe secondary processing technology, and has been widely used in petroleum chemical industry, municipal pipe network, energy power, engineering machinery and other fields, playing an important role in promoting the development of China’s national economy and the construction of local infrastructure in Shaanxi.
After decades of development, the process has gone through three stages: initial formation, rapid development and upgrading and optimization. It has gradually moved towards intelligence, greenization and high-endization, and the product quality, technical level and production efficiency have been significantly improved. The formulation and implementation of relevant standards have also standardized the development of the industry and enhanced the market recognition of the process. However, the process still faces some bottlenecks in the development process, such as the polarization of enterprise technical level, serious product homogenization, high energy consumption and insufficient core technology innovation ability.
In the future, with the continuous advancement of China’s manufacturing industry transformation and upgrading and the implementation of the “double carbon” goal, the Guanzhong medium and high frequency heat expansion process will face new development opportunities and challenges. It is necessary for enterprises to increase investment in technology research and development and equipment upgrading, strengthen the research of core technologies, promote intelligent and green production, and narrow the technical gap between enterprises; it is necessary to strengthen industry self-discipline and cooperation, promote the exchange of technology and experience, and avoid vicious competition and product homogenization; it is also necessary to combine market demand, expand the application field of products, develop high-end, high-performance heat-expanded seamless steel pipes, and enhance the core competitiveness of the industry. I believe that through the joint efforts of enterprises, research institutions and practitioners, the Guanzhong medium and high frequency heat-expanded seamless steel pipe process will achieve better development and make greater contributions to the development of China’s seamless steel pipe industry.
High Frequency Heat-Expanded Seamless Steel Pipes – Technology, Application and Development Trend
Hot-expanded Seamless Steel Pipe Process – Development History and Current Situation
Heat-Expanded Seamless Steel Pipe – Process Core Principle and Technical Analysis
ERW BLACK Pipes. Electric Resistance Welded (ERW) Pipes are manufactured from Hot Rolled Coils / Slits. All the incoming coils are verified based on the test certificate received from steel mill for their chemistry and mechanical properties. ERW pipe is cold-formed into a cylindrical shape, not hot-formed.
Seamless pipe is manufactured by extruding the metal to the desired length; therefore ERW pipe have a welded joint in its cross-section, while seamless pipe does not have any joint in its cross-section through-out its length. In Seamless pipe, there are no welding or joints and is manufactured from solid round billets.
The 3 elements of pipe dimension Dimension Standards of carbon and stainless steel pipe (ASME B36.10M & B36.19M) Pipe Size Schedule (Schedule 40 & 80 steel pipe means) Means of Nominal Pipe Size (NPS) and Nominal Diameter (DN) Steel Pipe Dimension Chart (Size chart) Pipe Weight Class Schedule (WGT)
Seamless pipes are manufactured using a piercing process, where a solid billet is heated and pierced to form a hollow tube. Welded pipes, on the other hand, are formed by joining two edges of steel plates or coils using various welding techniques.
Carbon steel pipe is highly resistant to shock and vibration which making it ideal to transport water, oil & gas and other fluids under roadways. Dimensions Size: 1/8″ to 48″ / DN6 to DN1200 Thickness: Sch 20, STD, 40, XS, 80, 120, 160, XXS Type: Seamless or welded pipe Surface: Primer, Anti rust oil, FBE, 2PE, 3LPE Coated Material: ASTM A106B, A53, API 5L B, X42, X46, X52, X56, X60, X65, X70 Service: Cutting, Beveling, Threading, Grooving, Coating, Galvanizing
Type A- Used where ample head room is available. Specific elevation is desirable. Type B- Used where headroom is limited. Head attachment is a single lug. Type C- Used where headroom is limited. Head attachment is side by side lugs
