External heating closed-volume thermally activated tube forming: A fundamentally new approach for hydroforming thick-walled tubes

The underlying principles of water’s equation of state (ES) and its associated pressure–volume–temperature (PVT) relationship, are employed for the purpose of producing “ultra-high” pressure within the closed volume of a thick-walled metal tube, resulting in a new and innovative hydroforming process. The process, called “Closed-Volume Thermally Activated” (CVTA) Tube Hydroforming, involves conducting a high level of heat through the walls of a thick-walled, metallic, water-containing closed tube. Experimental validation of the concept is presented, and potential applications are discussed. This work represents a break-through in manufacturing technology, which, when further developed, is expected to enable manufacturers to expand significantly their manufacturing capability.