What is the maximum allowable rate of temperature change for components with rolled tube joints in a steam boiler?

The maximum allowable rate of temperature change for components with rolled tube joints in a steam boiler is 40℃ per hour. This value is important because rolled tube joints are sensitive to thermal stresses and rapid changes in temperature can lead to issues such as warping, cracking, or loosening of the joints.

The 40℃ per hour limit ensures a gradual thermal expansion or contraction of the materials involved, which helps maintain the integrity of the joints and the overall safety and efficiency of the boiler. Adhering to this standard prevents excessive thermal strain, contributing to the longevity and reliability of the boiler components.