Inconel Tanks Annealed / Aged for Space
Solar furnaces simulate the vacuum conditions of space, 10-4 Torr and lower. Vacuum conditions are not always required to heat treat parts destined for space, but the precise temperature and controlled environment of the vacuum chamber are needed to process critical parts.
ARDE, Inc. Norwood, NJ manufactures medium and large Inconel Pressurant Tanks that are used in launch vehicles and satellites. ARDE has shipped more than 4,000 tanks during six decades in the manned and unmanned spaceflight business with no in-service incidents.
Looking for an alternative source for their heat treating needs, Dennis Lederman, ARDE’s Quality Control Manager, visited Solar’s web site. His goal was to more efficiently vacuum heat treat the Inconel, cylindrical liners that are overwrapped with carbon fiber to make strong, lightweight tanks for space. Processing the cylinders requires a long cycle (over 20 hours) to solution anneal and precipitation age harden the cylinders in accordance with AMS 2774. Because of the cylinder’s size (up to 5 feet in length and 24 inches in diameter), Solar’s six foot furnaces make it possible to process a number of the cylinders in one furnace cycle to improve turnaround and reduce Arde’s costs.
The biggest challenge in meeting ARDE’s needs is in the quenching process after the annealing and aging cycles. The influx of the argon gas must be carefully controlled so it doesn’t crush the thin-walled (.028 – .040) cylinders. This is because the small orifice in the cylinders restricts the ability of the vessel to equalize with the surrounding pressure. Controlling the gas influx can be done manually, but Solar managers from quality, sales, and maintenance worked together and developed an automated system to guarantee consistency and mistake-proof the process. The automated system and resulting furnace modification was greatly appreciated by ARDE.
Production efficiency was achieved through automation and Solar’s larger vacuum furnace capacities. ARDE’s goals have been accomplished, contributing to NASA’s ongoing efforts to explore space and learn about planet earth.