Which material is commonly used for fittings in high-pressure water systems?

Steel is commonly used for fittings in high-pressure water systems due to its strength, durability, and high tensile strength characteristics. In environments where high pressures are present, materials must withstand significant forces without deforming or failing. Steel fittings can handle these conditions effectively, making them ideal for applications in industries such as power generation, oil and gas, and water distribution.

In contrast to steel, aluminum, while lightweight and resistant to corrosion, does not have the same strength and pressure-holding capabilities as steel, making it less suitable for high-pressure applications. Polyethylene is a flexible plastic material, which, although great for certain types of water systems, does not provide the pressure ratings required in high-pressure environments. Rubber, while useful for seals and gaskets in various applications, is not typically used for fittings subjected to high pressures due to its potential for deformation and failure under such conditions.

Therefore, steel is the most appropriate choice for ensuring safety and reliability in high-pressure water systems.