Which materials are commonly used in boiler construction?

The materials commonly used in boiler construction are steel, aluminum, and various alloys. These materials are favored due to their strength, durability, and ability to withstand high temperatures and pressures, which are critical in boiler operations. Steel, in particular, is extensively utilized for its excellent tensile strength and resistance to deformation, making it suitable for the structural components of boilers. Aluminum is valued for being lightweight and corrosion-resistant, though it is less common in high-pressure applications. Various alloys are also used to enhance specific performance characteristics, such as resistance to corrosion or heat.

In contrast, the other materials mentioned are not suitable for boiler construction due to their inadequate properties. Wood, plastic, and fiberglass cannot withstand the extreme conditions present in boiler environments. Concrete, brick, and stone lack the necessary thermal properties and structural strength required for the high-pressure systems in boilers. Lastly, while rubber and copper have specific applications in plumbing and electrical components of boiler systems, they are not used for the main structural framework of boilers. Consequently, the correct answer emphasizes the suitability of steel, aluminum, and various alloys in ensuring the reliability and efficiency of boiler systems.