In hydroforming, what type of pressure is used to shape a rectangular steel tube?

Hydroforming utilizes hydraulic pressure to shape materials, particularly metal tubes in this context. This process involves filling a tube with pressurized liquid, which then exerts uniform pressure against the interior walls of the tube. As the pressure builds up, it allows the tube to expand and take on the shape of a mold or die that surrounds it. The use of hydraulic pressure is essential in hydroforming because it provides the necessary force to manipulate the tube material without causing it to fracture or weaken. This method is particularly advantageous for creating complex shapes with a high degree of precision, making it widely used in the automotive industry for components where strength and lightweight properties are crucial. Other options like pneumatic pressure, mechanical methods, or vacuum are not suitable for this specific application, as they do not provide the same level of uniformity and control that hydraulic pressure does during the shaping process.