The main differences between seamless and welded pipes are:

Manufacturing Process:

Seamless Pipe: Seamless pipes are manufactured without any welding or joining process. They are formed by piercing a solid billet to create the cylindrical shape.

Welded Pipe: Welded pipes are made by rolling a flat plate into a pipe shape and then welding the seam.

Strength and Durability:

Seamless Pipe: Seamless pipes have uniform strength throughout the pipe and generally exhibit higher strength than welded pipes.

Welded Pipe: Welded pipes may have slightly lower overall strength due to the welding process, but advancements in welding techniques have improved this over time.

Appearance and Surface Quality:

Seamless Pipe: Seamless pipes have a smoother surface finish and can withstand higher pressure and temperature.

Welded Pipe: Welded pipes can have a visible seam on the inside and outside, which may require post-weld treatments for certain applications.

Cost:

Seamless Pipe: Seamless pipes are generally more expensive due to the complex manufacturing process and higher material costs.

Welded Pipe: Welded pipes are usually more cost-effective and readily available.

Availability:

Seamless Pipe: Seamless pipes are typically used for high-pressure applications where strength and reliability are crucial.

Welded Pipe: Welded pipes are commonly used for less critical applications or where cost is a significant factor.

In summary, the choice between seamless and welded pipes depends on factors like application requirements, budget considerations, and availability. Seamless pipes offer superior strength and appearance, while welded pipes are more cost-effective and widely used in various applications.