Q355B LSAW Steel Pipe DN500

Q355B LSAW steel pipe DN500:

the optimal pipe for medium-end large-flow transportation.

Q355B LSAW steel pipe DN500 (nominal diameter 500mm, corresponding to external diameter about 530mm) is a mid-end conveying pipe which combines Q355B low alloy material and longitudinal submerged arc welding technology, conforms to GB/T 9711 and GB/T 1591 standards, and gives consideration to large flow adaptation, structural strength and economy, and is widely used in medium and large conveying scenes such as municipal, industrial and energy. Its core value lies in the matching of the flow advantage of DN500 specification with the mechanical properties of Q355B material, and it has become the core choice for large-flow transportation in mid-range scenes. This paper analyzes its characteristics and application value with the subtitle of question sentence.

1. Material base: How does Q355B support large flow conditions?

As a low-alloy high-strength carbon steel, Q355B has a yield strength of ≥355MPa and a tensile strength of 470-630MPa, which is more than 40% higher than that of Q235. Q355B can stably withstand the pressure of 10-12MPa and meet the internal pressure requirements of DN500 for large-flow transportation. Its impact energy at -20℃ is more than or equal to 34 j, 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 match LSAW process without complicated processing, and it can control the cost while ensuring the strength, and its cost performance ratio far exceeds that of high alloy pipes.

2. Specification and technology: How to balance flow and stability?

Compared with DN450, DN500 can improve the transportation efficiency by more than 20%, which can meet the needs of energy supply in medium and large-scale areas and large-flow medium transportation in industry, while avoiding the construction difficulty and cost pressure of larger-diameter pipes. Using LSAW longitudinal submerged arc welding +UOE 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 structural stability of buried and open-air laying.

3. Core scenario: What medium and large transportation needs are adapted to?

Widely used in urban central heating trunk lines, large-scale park water supply and drainage pipe networks, small and medium-sized oil and gas gathering and transportation branch lines and cooling water transportation in chemical parks. In the municipal scene, it can cover a large area of heating and water supply, reducing the laying density of 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 simple anti-corrosion coating, and adapting to various laying environments.

4. Competitive advantage: Why is the mid-range high-traffic scenario the first choice?

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 high-alloy pipes, it does not need to bear the material premium, and can adapt to most scenes through simple corrosion protection. In the field of medium-end large-flow transportation, it realizes the precise balance of "flow reaching the standard, reliable strength and controllable cost", and its application cost performance is outstanding.