Stainless steel welded pipes are moving towards Seamless

Stainless steel welded pipes (ss welded pipe), as one of the indispensable materials in modern industry and daily life, are increasingly widely used. From petroleum, chemical industry to food processing, medical equipment, building structure, automobile manufacturing, stainless steel welded pipes are everywhere. However, with the advancement of science and technology and the continuous improvement of market demand, people's performance requirements for stainless steel welded pipes are getting higher and higher. Against this background, "seamless" stainless steel welded pipes came into being, and with its unique advantages, it is gradually changing the market pattern of traditional stainless steel welded pipes.

What is "seamless" stainless steel welded pipe?

In short, it means that through a special production process, the stainless steel welded pipe originally welded is close to or reaches the effect of seamless steel pipe in appearance and performance. The core of this technology is to eliminate the traces and stress concentration at the welding joints through heat treatment, cold drawing and other means, thereby improving the overall strength and sealing performance of the pipe.

It involves an "internal leveling" process. The stainless steel welded pipe internal and external weld leveling device is a reciprocating automatic rolling device with a built-in mandrel and a roller to roll the stainless steel welded pipe. By controlling the rolling strength and pass, the internal and external welds of the stainless steel welded pipe are leveled, the internal and external welds are completely removed, and the welds are flush with the parent material, making the stainless steel welded pipe closer to the seamless pipe.

The importance of "seamless" stainless steel welded pipe:

To understand the importance of "seamless" stainless steel welded pipe, we need to first understand the problems of traditional stainless steel welded pipes.

Since welds are inevitably produced during the welding process, this not only affects the aesthetics of the pipe, but more importantly, it will form stress concentration points at the welds and reduce the mechanical properties of the material. In addition, welds are also weak links in corrosion and are prone to leakage. Stainless steel welded pipes after "seamless" treatment can effectively avoid these problems.

Reasons for promoting the development of "seamless" stainless steel welded pipes:

1. Improve performance and approach the quality of seamless pipes

Weld quality optimization: The welds of traditional welded pipes may have defects such as pores and slag inclusions, which affect strength and corrosion resistance. Through advanced technologies such as laser welding and plasma welding, the weld strength can be close to the level of the parent material, significantly improving the overall performance.

Eliminate weak weld areas: Seamless treatment (such as cold rolling and vacuum annealing) can refine the weld grain structure, reduce stress concentration, and make the welded pipe more stable under high pressure and high corrosion environments.

2. Meet high-precision requirements

Dimension tolerance control: Through cold rolling, straightening and other processes, the outer diameter and wall thickness tolerances of seamless welded pipes can be controlled within ±0.05mm, which is suitable for fields with strict dimensional requirements such as precision machinery and semiconductor equipment.

Improved surface finish: Internal and external polishing technology makes the inner wall roughness (Ra) of the welded pipe ≤0.8μm, reducing fluid resistance, and suitable for sanitary applications such as food and medicine.

3. Reduce costs and improve economy

Compared with stainless steel seamless pipes, it has a greater price advantage: the production process of seamless pipes is complex and the cost is high, while the production efficiency of welded pipes is high. After seamless processing, similar performance can be achieved at a lower cost.

Adapt to large size and thin wall requirements: welded pipes can produce ultra-large diameter (such as φ4500mm) or ultra-thin wall (0.5mm) pipes, which are difficult to achieve with seamless pipes due to process limitations.

4. Expansion of application areas

Replace seamless pipes: In the fields of petrochemicals, nuclear power, hydrogen energy storage and transportation, seamless welded pipes gradually replace traditional seamless pipes, such as boiler pipes, heat exchanger pipes, etc.5.
Emerging market demand: The demand for high-precision and corrosion-resistant pipes in emerging industries such as new energy vehicle battery shells and semiconductor ultra-clean pipelines is growing, which promotes the development of seamless welded pipes

5. Technological progress promotes the maturity of seamless technology

Laser welding technology: Fiber laser welding replaces traditional TIG welding, with a welding speed increased by 3 times and a more uniform weld.
Cold rolling + annealing process: cold rolling strengthening and vacuum annealing are used to eliminate residual stress, so that the mechanical properties of the welded pipe are close to those of seamless pipes.
Intelligent detection: AI visual system monitors the quality of welds in real time to ensure that the product qualification rate is >99.5%.

Advantages of "seamless" stainless steel welded pipes:

Specifically, the advantages of "seamless" stainless steel welded pipes are mainly reflected in the following aspects:

1. Improve strength and durability
After the "seamless" treatment, the stress inside the pipe is evenly distributed, reducing the risk of fracture caused by stress concentration. This enables the pipe to withstand higher pressures and more severe environmental conditions, extending its service life.

2. Enhance sealing and corrosion resistance
After eliminating the potential weakness of the weld, the overall sealing performance of the pipe has been significantly improved. At the same time, due to the smoother and flatter surface, the adhesion area of the corrosive medium is also reduced, thereby improving the corrosion resistance.

3. Improve aesthetics and market competitiveness
The "seamless" stainless steel welded pipe is closer to high-end seamless steel pipe products in appearance, meeting some application scenarios with special requirements for aesthetics. At the same time, due to the improvement of performance, the market competitiveness of the product has also been enhanced.

4. Cost advantage
In the case of mass production, the cost of stainless steel welded pipes is more than 20% lower than that of seamless pipes.

5. Market demand
With the development of industry, the demand for stainless steel pipes in various industries is increasing, especially the demand for high-quality, low-cost pipes is more urgent. "Seamless" stainless steel welded pipes can meet the market's requirements for pipe performance and cost.

Achieving "seamless" is not easy:

Of course, it is not easy to achieve "seamless".

This requires manufacturers to have advanced production processes and technical equipment support. For example, use high-precision digital control systems to ensure the stability and consistency of the welding process; use heat treatment technology and cold drawing processes to optimize metal structure and eliminate stress; and use precision testing equipment to ensure that each pipe meets the expected quality standards.

In addition to technical challenges, cost control is also a major problem in the promotion of "seamless" stainless steel welded pipes. Due to the more complex production process and higher requirements for raw material quality, its production cost has increased compared to ordinary welded pipes.

Therefore, how to reduce costs while ensuring product quality is a direction that manufacturers need to explore continuously.

Looking to the future:

With the continuous advancement of technology and the further expansion of the market, "seamless" stainless steel welded pipes are expected to be used in more fields. Whether it is for the aerospace field that pursues extreme performance, or for the green building industry that focuses on environmental protection and energy saving, or even in daily household products, "seamless" stainless steel welded pipes will play an increasingly important role.

The emergence of "seamless" stainless steel welded pipes marks a major innovation in this field. It not only solves some inherent problems of traditional welded pipes, but also opens up new possibilities for future materials science and applications.

Conclusion:

The "seamless" trend of stainless steel welded pipes is the result of the combined effect of market demand, technological progress and economy. By optimizing welding processes, cold working and heat treatment, while maintaining cost advantages, the performance of welded pipes gradually approaches or even exceeds that of some seamless pipes, making them more and more widely used in high-end industrial fields.

Read more: 7 Things to consider when purchasing stainless steel ERW pipes or Stainless Steel ERW vs Seamless Pipe