Stainless steel pipes are mainly divided into seamless pipes and welded pipes according to the production process. There are significant differences between the two in manufacturing methods, performance characteristics and application fields.

1. Different production processes

Seamless pipe: It is made by hot rolling or cold rolling process, and the solid steel billet is perforated and rolled, and there is no weld as a whole.

Welded pipe: It is made by welding (such as high-frequency welding, laser welding) after the stainless steel coil or strip is rolled and formed, and there is a longitudinal or spiral weld.

2. Differences in appearance and structure

Seamless pipe: The inner and outer walls are smooth and uniform, without seams, and the overall consistency is better.

Welded pipe: There may be slight bulges or color differences at the weld, and further processing (such as polishing) is required to improve the appearance.

3. Comparison of mechanical properties

Strength: Seamless pipes have no welds, and the overall pressure bearing capacity is stronger, which is suitable for high-pressure environments.

Toughness: The weld area of ​​the welded pipe may become a weak point, especially under low temperature or impact load.

4. Corrosion resistance difference

Seamless pipe: no weld, more uniform corrosion resistance, suitable for strong acid, strong alkali or high salt environment.

Welded pipe: if the welding process is not good, intergranular corrosion is prone to occur in the weld area, and high-quality welded pipes (such as solution treatment) need to be selected.

5. Size and specification restrictions

Seamless pipe: limited by the rolling process, large diameter (such as >500mm) or ultra-thin wall pipe production cost is high.

Welded pipe: large diameter, extra-long or special-shaped pipes can be flexibly produced, and thin-walled pipes are cheaper.

6. Price and delivery cycle

Seamless pipe: the production process is complex, the price is usually 30%-50% higher than the welded pipe, and the delivery cycle is longer.

Welded pipe: high production efficiency, low cost, suitable for bulk purchase.

7. Typical application scenarios

Select seamless pipes:

High-pressure pipelines (petroleum, chemical, boilers)

Precision instruments (semiconductors, medical devices)

Aerospace hydraulic systems

Select welded pipes:

Architectural decoration (handrails, guardrails)

Low-pressure fluid transportation (water pipes, gas pipes)

Structural support (scaffolding, furniture frames)

8. How to choose?

Prefer seamless pipes: if the budget is sufficient and high pressure bearing and high corrosion resistance are required.

Optional welded pipes: for low pressure, non-harsh environments, or large size/low cost scenarios.