Cleveland-based Consolidated Precision Products has ordered a new vacuum heat-treating furnace for aero turbine blades investment cast at the group’s Rzeszów foundry in Poland. It will be the seventh vacuum furnace CPP has contracted from Seco/Warwick Group, which have been installed at its various operations in the U.S., Mexico, and Europe.
“This will be a furnace for annealing blades cast from single crystals,” explained Seco/Warwick vice president Maciej Korecki, in a published announcement. “The unique feature of this furnace is the modifications enabling very clean annealing processes for single-crystal castings. We have implemented a vacuum furnace equipped with a molybdenum heating chamber, partial pressure system, dew-point sensors, and a highly efficient high vacuum system.
“As one of the largest global manufacturers of vacuum devices for metal heat treatment, we significantly feel the revival in the aviation market,” Korecki added.
Aero and industrial gas engines are assembled from highly specialized parts, among which are single-crystal blades for the turbine fans. Single-crystal casting forms the blades from a superalloy “seed crystal” in a controlled vacuum furnace chamber. The process known as directional solidification results in a single, uninterrupted crystal structure.
Annealing the castings is critical step to relieve the residual stresses and prevent recrystallization, to enhance the parts’ mechanical strength and internal creep resistance, by minimizing weak grain boundaries forming within the part.
Seco/Warwick designs and manufactures industrial furnaces and heat treatment equipment, and specializes in vacuum heat treatment and aluminum thermal processing technologies.
The 1.5-bar abs. vacuum furnace to be supplied to Consolidate Precision Products will be based on a standard design, with a working space of 900x900x1200 mm, screen insulation, and metal heating elements specified to match the characteristics and needs of cast parts.
“The round heating chamber allows for the placement of oversized elements,” stated sales engine Paweł Okińczyc. “The furnace has been expanded and modified with dedicated options to meet very high requirements: high vacuum, temperature distribution, operation at high temperatures around 1300 degrees, and cleanliness of processes.”
He continued: “The device will be used for annealing blades cast from single crystals. Its advantage is the molybdenum heating chamber, which prevents direct heat loss to the wall of the vacuum chamber and ensures very high process cleanliness. The efficiency of the processes carried out is also influenced by the ability to cool in 1.5 bars of argon. Thanks to inverter control, we can regulate the cooling speed in the appropriate process segment.”
CPP foundries supply complex jet-engine parts to engine manufacturers and maintenance suppliers, who prioritize product quality and reliability.
“This is not our first collaboration with the Seco/Warwick Group,” according to Dariusz Szawara, foundry director for DS/SX at Consolidated Precision Products. “Their equipment has been working in our plants for many years. This particular vacuum furnace will be used for the production of a new line of jet engine blades from single crystals.
“The turbine elements used in the aviation industry operate under high mechanical loads at temperatures close to their melting point and in an aggressive corrosive environment,” Szawara explained. “Therefore, we cannot afford structural defects that would affect the quality or durability of our products.”