Superalloy Forging with Segmented Metal Insulation
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Solution Overview
Problem
Existing closed-die forging methods face challenges in maintaining temperature control and preventing surface cracks during the forging of superalloys, particularly due to heat loss and the difficulty in monitoring and controlling the temperature of the material being forged, which affects the quality of the final product.
Innovation Solution
A closed-die forging method where the portion of the superalloy that contacts the lower die is covered with a metal heat-insulation member, except for the part that contacts the upper die, allowing for effective heat insulation and temperature monitoring, while the metal heat-insulation member is made from stainless steel to prevent scattering and ensure proper deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the whole of the member to be forged is covered with a heat-insulation member, then temperature control is improved, but temperature monitoring becomes difficult
Solution Approach 1:
The heat-insulation member is segmented into multiple parts: a first heat-insulation member covering the lower surface, a second heat-insulation member covering the side surface, and a third heat-insulation member covering the upper surface. This segmentation allows the upper surface to be insulated while still permitting temperature monitoring through the third heat-insulation member's material selection or configuration.
Solution Approach 2:
The third heat-insulation member acts as an intermediary that provides thermal insulation while allowing temperature monitoring. By selecting materials or configurations that permit thermal radiation or conduction through the insulator, temperature can be monitored without direct contact, resolving the contradiction between insulation and monitoring.
2Temperature
If glass fiber or ceramic fiber is used in the heat-insulation member, then heat insulation is improved, but fiber scattering and deposition occurs
Solution Approach 1:
The invention changes the material parameter of the heat-insulation member from fibrous materials (glass fiber, ceramic fiber) to sheet materials (heat-insulation sheets). This parameter change eliminates the scattering and deposition problems while maintaining effective heat insulation through the sheet structure.
Solution Approach 2:
The heat-insulation member is constructed as a composite structure using heat-insulation sheets that may have multiple layers or combinations of different insulating materials, achieving effective insulation without the harmful fiber scattering associated with traditional fibrous insulators.
3Temperature
If the member to be forged is covered with heat-insulation material, then temperature maintenance is improved, but plastic deformation capability deteriorates
Solution Approach 1:
The heat-insulation coverage is segmented to leave the upper surface (at least partially) uncovered or covered with a material that permits deformation. This allows the lower and side surfaces to maintain temperature while the upper surface remains accessible for monitoring and deformation control during forging.
Solution Approach 2:
Different regions of the member have different insulation characteristics: the lower surface has strong insulation to maintain temperature, the side surface has moderate insulation, and the upper surface has reduced or selective insulation to allow deformation and monitoring. This local differentiation resolves the contradiction between temperature maintenance and deformation capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method prevents surface cracks, allows for easy temperature control, and achieves plastic deformation that fills the cavity end portions of the die, resulting in a product with fine crystal grains and excellent mechanical characteristics, suitable for high-strength components like airplane turbine disks.
Implementation Method 1
covering the whole of a portion of the member to be forged that contacts the lower die with a metal heat-insulation member prior to forging
Implementation Method 2
hammer-forging the member to be forged with a reciprocating upper die... achieves plastic deformation that fills the cavity end portions of the die
Data Source
Figure 1
Figure 2
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AI summary
Provided are: a closed-die forging method capable of preventing a temperature decrease in a to-be-forged member during forging, easy temperature monitoring during forging, and causing cavity end portions of a die to be filled with the to-be-forged member; and a method of manufacturing a forged article using the closed-die forging method. The closed-die forging method, which involves placing a heated to-be-forged member on a lower die and hammer-forging the to-be-forged member with a reciprocating upper die, includes covering the whole of a portion of the to-be-forged member that contacts the lower die with a metal heat-insulation member prior to forging, except for at least a part of a portion that contacts an upper die during forging, and then forging the to-be-forged member integrally with the metal heat-insulation member. Preferably, the to-be-forged member is a superalloy and the metal heat-insulation member is stainless steel. Further preferably, the to-be-forged member is forged into a disk shape. The method of manufacturing a forged article includes heat-treating a forged material obtained by the closed-die forging method at temperatures not lower than recrystallization temperature.