Q355B LSAW Steel Pipe DN750

1. Material adaptation: Can Q355B bear DN750 working condition?

Q355B low-alloy high-strength carbon steel can stably bear the working condition of DN750, and its yield strength is ≥355MPa, tensile strength is 470-630MPa, which is more than 50% higher than that of Q235. It can withstand the pressure of 15-17MPa and calmly cope with the internal pressure, soil load and environmental impact of large-diameter transportation. The impact energy of this material at -20℃ is ≥34J, and its low-temperature toughness is excellent. It is suitable for underground laying in cold areas, easy to weld and corrosion-resistant, and can accurately match LSAW process. The alloy elements such as vanadium and titanium contained in it further enhance the corrosion resistance, control the cost while ensuring the strength, and the cost performance ratio far exceeds that of high-alloy large pipes.

2. Specification and process: How to balance super-large flow and structural stability?

Compared with DN700, DN750 specification improves the transportation efficiency by more than 9%, which can meet the needs of centralized energy supply and industrial mass media transportation in super-large areas and adapt to large-scale centralized transportation scenarios. Using LSAW longitudinal submerged arc welding +UOE precision forming process, the weld strength is equal to that of the base metal, the stress distribution is uniform, and there is no hidden danger of stress concentration in spiral welded pipe; After forming, the residual stress is eliminated by expanding and tempering, and the tolerance of outer diameter is controlled within 0.5%, which ensures the long-term structural stability of buried and open-air laying and adapts to various wall thickness specifications.

3. Core application: What major engineering scenarios are covered?

It is widely used in central heating main pipes in megacities, large municipal water supply and drainage main networks, medium-sized oil and gas gathering and transportation trunk lines and core circulating water pipes in chemical parks. In the municipal scene, it can cover the core energy supply and water supply network of the whole city, greatly simplifying the laying density of the pipe network; In industrial and energy scenes, long-term stable service can be achieved by adapting to low corrosive medium, medium and high pressure working conditions and FBE anticorrosive coating, adapting to complex geological and climatic conditions and meeting the transportation needs of large-scale key projects.

4. Competitive advantage: Why is the large-scale transportation scene optimized?

Compared with Q235 pipe with the same specification, it has higher strength and wider application conditions. Compared with seamless steel pipe, the cost is reduced by more than 30%, and the mass production efficiency is better. Compared with larger diameter pipes, the construction is less difficult and the cost is controllable. At the same time, the flow fully meets the needs of large-scale projects. In the field of large-scale transportation, the precise balance of "flow, strength and cost" is realized, and the application cost performance is outstanding.