Q355B LSAW Steel Pipe DN700

1. Material adaptation: Can Q355B bear DN700 working condition?

Q355B low-alloy high-strength carbon steel can stably bear the working condition of DN700, and its yield strength is ≥355MPa, tensile strength is 470-630MPa, which is more than 40% higher than that of Q235. It can withstand the pressure of 14-16MPa 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, and it is easy to weld and resist corrosion. It can accurately match the LSAW process, control the cost while ensuring the strength, and its cost performance ratio far exceeds that of large-scale high-alloy pipes.

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

Compared with DN650, the transport efficiency of DN700 is improved by more than 10%, which can meet the needs of centralized energy supply and industrial mass media transport in super-large areas and adapt to large-scale centralized transport 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.

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 realized by adapting to low corrosive medium, medium and high pressure working conditions and FBE anticorrosive coating, and adapting to complex geological and climatic conditions.

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.