ASME-Landmark:First Hot Isostatic Processing Vessels

In 1955, the Atomic Energy Commission issued a challenge to researchers at Battelle Memorial Institute's Columbus Laboratories in Columbus, Ohio. The challenge was simple: develop a process to bond components of small Zircaloy-clad pin-type nuclear fuel elements while maintaining strict dimensional control.

A team of researchers led by Dr. Russell Dayton, Henry Saller, Stan Paprocki, and Edwin Hodge developed a technique first called gas-pressure bonding but now referred to as hot isostatic processing (HIP). The scientists used a three-foot-long stainless-steel tube, plugged and welded on one end and threaded to accept a high-pressure valve on the other end, which they pressurized to approximately 2,000 pounds per square inch and inserted into a heat-treat furnace at a temperature of about 1,500 degrees Fahrenheit. This small, simple pressure vessel was followed by larger, more complex vessels throughout the 1950s and into the 60s and 70s.

HIP uses gas pressure and temperature to fabricate parts and products, bond and densify materials, consolidate powders, and heal defects. The process was soon extended beyond the bonding of Zircaloy-clad pin-type nuclear fuel elements and applied to compact powders for use in tool steel, superalloys for jet engines, and materials for space applications. The strict dimensional control provided in a HIP vessel makes it useful as a manufacturing technique for near-net-shape processing and other complex fabrications.

Today, HIP is used in industry worldwide to produce advanced alloy and ceramic products, particularly complex-shaped parts and products. See ASME website for more information