Is It Better for High-pressure Boiler Seamless Pipes To Have Thicker Walls?

The wall thickness of the high-pressure boiler seamless pipe is not the thicker the better, but needs to be scientifically designed and selected according to the actual working conditions, material properties, safety specifications and economy. What are the potential problems of excessive wall thickness? How to scientifically determine the wall thickness?

Potential problems of excessive wall thickness

1. Increased material cost

The increase in the wall thickness of the boiler seamless pipe will directly lead to an increase in the use of steel pipes and an increase in material costs. Especially for special steels such as high-pressure boiler tube, the cost difference may be very significant. In addition, in some hydraulic systems, the manufacture of hydraulic tubes is also affected by the wall thickness.

2. Increased weight and installation difficulty

Excessively thick tube walls will increase the overall weight of the boiler system, put higher requirements on the supporting structure, and increase the difficulty of installation and welding, which may affect the construction efficiency.

3. Decreased thermal efficiency

The excessive wall thickness of the boiler seamless pipe will reduce the heat conduction efficiency, resulting in uneven heat transfer during boiler operation, which may affect the overall energy efficiency and even cause local overheating or stress concentration problems.

4. Thermal stress risk

Under high temperature and high pressure environment, excessively thick pipe wall may generate greater thermal stress due to uneven thermal expansion. Long-term operation may accelerate fatigue damage and shorten service life. It may also affect the valves and other matching valves.

Core factors for scientifically determining wall thickness

1. Working conditions

Pressure and temperature: According to the design pressure and temperature of the boiler, the minimum theoretical wall thickness is calculated by formula (such as the wall thickness calculation formula in ASME B31.1 or GB 5310 standard).

Medium characteristics: If the medium is corrosive or contains impurities, additional corrosion allowance is required.

2. Material properties

The strength grade of the steel of the seamless pipe (such as 20G, 15CrMoG, etc.) determines its pressure bearing capacity. High-strength materials can appropriately reduce the wall thickness. High-temperature creep resistance, hydrogen corrosion resistance, etc. need to match the boiler operating environment.

3. Safety specifications and standards

Boiler seamless pipes must comply with national standards or international standards (such as ASME SA-213) to ensure that the wall thickness meets the safety margin requirements.

4. Balance between economy and service life

On the premise of meeting safety, choose the solution with the best cost and performance to avoid over-design.

Suggestions for practical application

1. Strictly follow the design specifications

Use the formula to calculate the minimum wall thickness and refer to relevant standards and specifications. For different types of pipes, the wall thickness also needs to be determined according to their specific design specifications.

2. Pay attention to the manufacturing process

Select high-quality seamless pipes to ensure the uniformity of wall thickness (tolerance is usually ±10%) and avoid local weak points.

3. Adjustment of working condition adaptability

For boilers in highly corrosive environments or frequent start-up and shutdown, the wall thickness can be appropriately increased or more corrosion-resistant materials (such as composite stainless steel pipes) can be selected.

Conclusion

The wall thickness of high-pressure boiler seamless pipes needs to be determined through scientific calculations and comprehensive evaluations. Blindly increasing the wall thickness not only increases costs, but may also cause reduced thermal efficiency and structural risks. The key is to balance performance, life and economy while meeting safety specifications. It is recommended to consult professional engineers or refer to the boiler design manual when selecting to ensure that the material selection is reasonable and reliable.

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