What Is The Scrapping Standard for Boiler Tubes?

In daily operation, we often need to judge whether equipment or components are still suitable for continued use. The scrapping standard is used to determine the basis for this judgment: when the performance, structure or safety index of a certain equipment or component drops to the point where it is no longer suitable for safe operation or economic benefits, it should be eliminated, replaced or decommissioned in a timely manner. Simply put, the scrapping standard provides a set of quantitative or qualitative judgment bases to prevent safety hazards caused by aging, wear or damage of equipment.

Boiler tube refers to steel materials with openings at both ends and hollow sections, and their length is relatively large compared to the surrounding area. According to the production method, they can be divided into seamless steel pipe and welded steel pipe. As an important part of industrial boilers, the safety and service life of boiler tubes are directly related to the normal operation of boilers. So, what is the scrapping standard for boiler tubes? What factors will affect the life of boiler tubes?

The scrapping standard for boiler tubes is usually that the wall thickness wear exceeds 15% of the tube thickness or the strength residual rate is less than 5%. The life of boiler tubes is affected by many factors such as material, welding, manufacturing process, use environment and operating status. The following will introduce you in detail.

Boiler tube scrapping standard

The scrapping standard of boiler tubes is not fixed, but is usually mainly judged based on the degree of wear of the tube wall thickness and the residual rate of strength. Generally speaking, if the wall thickness of the boiler tube is worn more than 15% of the tube thickness, or its residual rate of strength is less than 5%, then the boiler tube needs to be scrapped and replaced.

1. Wall thickness wear exceeds 15%

When the original tube wall thickness wears more than 15% due to long-term high temperature, high pressure, corrosion and other working conditions, the pipeline safety performance is significantly reduced.

2. Strength residual rate is less than 5%

If the residual bearing capacity (residual strength) of the pipeline drops to less than 5% of the original design value after long-term operation, it is difficult to meet the safe operation requirements.

The formulation of these two standards is based on the principles of thermodynamics and material mechanics. The purpose is to ensure that during the operation of the boiler, the pipeline can withstand high temperature and high pressure working conditions and avoid safety accidents such as bursting caused by excessive local wear or material fatigue.

Factors affecting the life of boiler tubes

1. Material

The material of the boiler tube is the basis for determining its service life. Different materials have different corrosion resistance and high temperature resistance. For example, high-quality high-temperature boiler tube materials such as 20G, 12CrMoVG, etc., often have a service life of more than 10 years.

2. Welding quality

The welding quality of boiler tubes has a direct impact on their integrity and safety. Poor welding may cause cracks, air leaks and other problems in the pipeline, which in turn affects the service life.

3. Manufacturing process

The manufacturing process that meets national standards can ensure the quality of boiler tubes. From pipe procurement to processing and forming, every link may affect the performance and service life of the final product. Especially for some high-precision occasions, such as the manufacture of precision tube, slight differences in the process may lead to huge changes in product performance.

4. Use environment

Boiler tubes work in harsh environments such as high temperature, high pressure, and corrosion. These environmental factors will accelerate the wear and aging of the pipeline, thereby shortening its service life.

5. Operating status

Reasonable operating parameters such as temperature, pressure and water quality control are crucial to extending the service life of boiler tubes. Improper operating conditions may cause premature damage to the pipeline.

Summary

In summary, in order to ensure the safety of boiler tubes and extend their service life, we should start from selecting high-quality materials, improving welding and manufacturing process levels, improving the use environment, and optimizing the operating status. At the same time, regular inspection and maintenance are also essential measures.