What type of construction is typically used for tubes in high pressure service?

Seamless construction is typically used for tubes in high-pressure service due to its inherent advantages in structural integrity and resistance to high stress. In seamless tubes, the material is molded into tubular form without any seams or joints, which significantly minimizes the risk of failure under high pressure. This construction method ensures a uniform wall thickness and improved performance in extreme conditions, as there are no weak points where pressure can exert stress.

High-pressure applications require materials that can withstand not only the internal pressure but also potential thermal and mechanical stress during operation. Seamless construction helps to ensure that the material has the required tensile strength and ductility to safely operate in such environments.

Resistance welded, lap welded, and fin-tube designs have their applications but are less ideal for high-pressure scenarios. Resistance welding can introduce weak points at the seams, which are vulnerable to failure under pressure. Lap welding can also create areas of weakness at the joints. Fin-tube designs are mainly used for heat exchange purposes and not specifically for pressure retention, which makes them less relevant in high-pressure tube applications. Thus, seamless construction stands out as the most suitable choice for ensuring safety and reliability in high-pressure service.