Details of Q690E straight seam welded steel pipe commonly used in industrial projects

Q690E straight seam welded steel pipe is a high-strength low-alloy structural steel welded pipe, that is widely used in engineering machinery, bridge construction, high-pressure vessels, mining equipment, and other fields. Its excellent mechanical properties and welding properties make it an indispensable and important material in modern industry.

First, the material properties of Q690E straight seam welded steel pipe

Q690E is a high-strength low-alloy structural steel. The "Q" in its grade represents the yield strength, "690" means the yield strength is 690MPa, and "E" represents that the steel has good low-temperature impact toughness. While maintaining high strength characteristics, Q690E straight seam welded steel pipe also has good plasticity and toughness, which can meet the use requirements under complex working conditions. The chemical composition of Q690E steel is carefully designed, usually containing appropriate amounts of carbon, manganese, silicon, and other elements, and adding micro-alloy elements such as niobium, vanadium, and titanium to refine the grains and improve strength and toughness. Its mechanical properties are as follows: tensile strength ≥ 770MPa, yield strength ≥ 690MPa, elongation ≥ 14%, and good impact toughness can be maintained at -40℃ low temperature.

Second, the production process of Q690E straight seam steel pipe

The production process of Q690E straight seam welded steel pipe mainly includes steel plate pretreatment, forming, welding, heat treatment, and finishing. Among them, forming and welding are key processes that directly affect the quality and performance of steel pipes.

1. Steel plate pretreatment: Select Q690E steel plates that meet the requirements, and undergo pretreatment such as leveling and trimming to ensure that the surface of the steel plate is flat and defect-free.

2. Forming: Use JCOE or UOE forming process to gradually bend the steel plate into a tubular shape. During the forming process, the bending radius and forming angle must be strictly controlled to avoid stress concentration.

3. Welding: Use multi-wire submerged arc welding (SAW) or high-frequency welding (ERW) process. The heat input must be accurately controlled during welding to avoid performance degradation in the heat-affected zone of the weld. After welding, non-destructive testing (such as ultrasonic, X-ray, etc.) is required to ensure the quality of the weld.

4. Heat treatment: Tempering treatment (quenching + tempering) is carried out according to demand to optimize the comprehensive mechanical properties of the steel pipe.

5. Finishing: Including straightening, flat head, water pressure test, and other processes to ensure that the geometric dimensions and sealing performance of the steel pipe meet the standards.

Third, the application field of Q690E straight seam welded steel pipe

Due to its high strength, high toughness, and good welding performance, Q690E straight seam welded steel pipe is widely used in many fields:

1. Engineering machinery: used to manufacture key load-bearing components such as crane booms and excavator chassis, which can reduce the weight of equipment and improve the load-bearing capacity.

2. Bridge construction: suitable for piers and main beam structures of large-span bridges, especially in low-temperature areas.

3. High-pressure vessels: used to manufacture high-pressure pipelines and storage tanks in the petroleum and chemical industries, with excellent pressure resistance.

4. Mining equipment: As mining hydraulic supports, conveyor structural parts, etc., it has good impact resistance and wear resistance.

5. Marine engineering: Suitable for steel structures in harsh environments such as offshore platforms and submarine pipelines.

Fourth, the market prospects of Q690E straight seam steel pipes

With the continuous investment in my country's infrastructure construction and the rapid development of the high-end equipment manufacturing industry, the demand for high-strength steel has increased year by year. As a representative product of high-performance steel, Q690E straight seam welded steel pipe has broad market prospects.

1. Policy support: The national "14th Five-Year Plan" clearly proposes to vigorously develop high-end equipment manufacturing and green buildings, which will directly drive the demand for high-strength steel.

2. Technology upgrade: With the continuous advancement of welding technology and heat treatment technology, the quality and performance of Q690E straight seam welded steel pipes will be further improved, and the scope of application is expected to expand.

3. Import substitution: Domestic steel mills have gradually realized the localization of Q690E grade steel through technical research, reducing user procurement costs.

4. Emerging fields: In emerging fields such as wind turbine towers and nuclear power equipment, Q690E straight seam welded steel pipes have great application potential.

Fifth, matters needing attention in purchasing Q690E straight seam welded steel pipes.

1. Certification qualifications: Choose manufacturers that have passed ISO9001, API, and other certifications to ensure reliable product quality.

2. Test report: Require suppliers to provide complete mechanical properties test reports and non-destructive testing reports.

3. Welding process assessment: For important projects, the welding process assessment report of steel pipes needs to be reviewed.

4. After-sales service: Choose suppliers that can provide technical support and quality assurance.

Sixth, Conclusion

Q690E straight seam welded steel pipes are becoming the preferred material in the field of high-end steel structures due to their excellent comprehensive performance. With the continuous improvement of manufacturing processes and the accumulation of application experience, its market share at home and abroad is expected to expand further. For users, understanding material properties, rational selection, and choosing reliable suppliers are the keys to ensuring project quality and safety. In the future, with the research and development of new materials and new processes, the performance of Q690E straight seam welded steel pipe will continue to improve, providing possibilities for application in more fields.