What do "Q" and "345" represent in the steel grade "Q345"?
In the steel grade "Q345", "Q" represents "yield strength". "345" represents the minimum yield strength of the steel, measured in megapascals (MPa). Therefore, the minimum yield strength of Q345 steel is 345 MPa.
Which boiler components are Q345 steel pipes mainly used in?
Q345 steel pipes are mainly used in various boiler components, including water-cooled wall tubes, steam pipes, and arch brick tubes, and are particularly suitable for medium and low-pressure applications. Their excellent comprehensive mechanical properties, weldability, and low-temperature performance make them suitable for these structurally high-load components in boiler systems.
How can the quality of steel pipes be initially judged from their appearance?
The quality of steel pipes can be initially judged by inspecting surface defects, ensuring correct dimensions, and checking end cuts and markings.
How does operating pressure affect the selection of boiler steel pipe wall thickness?
The operating pressure directly determines the required wall thickness of the boiler steel pipes, because the higher the pressure, the greater the wall thickness required for a safe seal.
What are the main differences between Q345 steel pipes for boilers and Q345 steel pipes for general structures?
The main difference is that Q345 steel for boilers (especially the Q345R grade) is a special alloy specifically designed for pressure vessels. Compared to general-purpose Q345 steel for general structures, it has more stringent requirements for impact toughness and weldability.
