Whether welded pipe is cheaper than seamless pipe depends on various factors including material, diameter, wall thickness, and production process. Generally, welded pipes tend to be less expensive than seamless pipes for several reasons:

Manufacturing Process:

Welded pipes are manufactured by welding strips or plates of steel together to form the pipe shape, which is generally a more cost-effective process compared to the seamless pipe manufacturing process, which involves heating and molding a solid billet of steel.

Material Cost:

The raw material cost for welded pipe production is typically lower since it involves using rolled steel plates or coils instead of solid steel billets used in seamless pipe production.

Labor Cost:

Labor costs for producing welded pipes are often lower since the process involves fewer steps and can be more easily automated compared to seamless pipe manufacturing.

Quality Control:

Seamless pipes undergo more stringent quality control measures due to the nature of their production process, which can add to the overall cost.

However, it's essential to consider other factors such as application requirements, durability, and performance when choosing between welded and seamless pipes. In some cases, the cost difference may be negligible compared to the benefits provided by seamless pipes, such as higher strength, better corrosion resistance, and suitability for high-pressure applications.

Ultimately, the choice between welded and seamless pipes should be based on factors beyond just cost, including the specific requirements of the project or application.