For steam service, what type of joint is preferable on a high pressure boiler?

In high-pressure boiler applications, a welded joint is preferable due to its ability to provide a seamless, strong, and durable connection that can withstand the extreme conditions associated with steam service. Welded joints create a continuous bond between pipes, which minimizes potential weak points that could lead to failures under high pressure.

This type of joint is particularly important in high-pressure systems where the risk of leaks or mechanical failure can have serious safety implications. Additionally, welded joints can handle thermal expansion and contraction more effectively than other types of joints, further enhancing their suitability for high-pressure environments.

Other joint types, such as flanged, screwed, and compression joints, may not offer the same level of integrity and security at high pressures. Flanged joints, while easier to disassemble, have bolt connections that can loosen over time. Screwed joints can also be prone to leaks under stress, and compression joints might not maintain the required pressure sealing under extreme conditions. Therefore, for the reliability and safety required in high-pressure boiler systems, welded joints are clearly the best choice.