The Chevy SSR hydroformed frame
The production version of the Chevrolet SSR uses a frame with fully hydroformed steel side rails. The hydroformed frame features great strength and stiffness, relatively low weight and precise quality.
Ted Robertson, chief engineer for the Chevrolet SSR said: "A traditional stamped frame with this amount of strength and rigidity would weigh roughly 20% more than this one. That strength allows the frame to take on the road inputs, which lets the suspension do its job precisely."
Hydroforming is a process of shaping steel tubes through the application of water at extremely high pressure. It replaces traditional stamping processes, preserving more of the steel's strength and stiffness as it goes through the forming process. Hydroforming is done at low temperatures to retain the material's strength throughout the forming process, unlike high temperature processes which decrease material strength.
Hydroforming is also efficient and environmentally friendly, dramatically reducing overall material usage and scrap.
GM pioneered automotive hydroforming on the Chevrolet Corvette and used this process for the first time for a truck frame on the Chevy Silverado, Tahoe and Suburban. The all-new 2002 Chevy TrailBlazer marked the first time hydroforming has been used for the entire length of a truck frame's side rails. In a way, the process has been validated by Dodge, which will use hydroforming for the next-generation Durango and Dakota.