Ring Forging Sequence for Reduced Dead Metal Regions
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Solution Overview
Problem
The existing ring molded article manufacturing methods face challenges in efficiently producing turbine disks with reduced dead metal regions, as material adherence to molds during forging leads to temperature discrepancies and rough surface structures, making it difficult to achieve desired mechanical characteristics, and the process is hindered by the need to remove excess material and manage convex portion alignment.
Innovation Solution
The method involves first forging a material with an inclined peripheral wall, followed by drilling and ring-rolling, and then using molds with specific concave portions to apply controlled pressure during second forging, where the ring material is inclined relative to the center axis by 7-40 degrees to reduce dead metal regions and ensure proper convex formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ring material is placed inside the molds and subjected to second forging, then the convex portions are formed and mechanical strength is improved, but the surface region adheres to the molds causing temperature decrease and dead metal region formation
Solution Approach 1:
The ring material is pre-heated before being placed in the molds for second forging. This preliminary heating action ensures that the surface region maintains sufficient temperature during the initial contact with the molds, preventing premature adhesion and dead metal region formation, while still allowing the forging process to impart strain and improve mechanical strength
Solution Approach 2:
A release agent or coating is applied to the mold surfaces before placing the ring material. This intermediary layer prevents direct adhesion between the ring material surface and the mold, reducing heat transfer to the molds and preventing dead metal region formation, while still allowing the forging pressure to effectively shape the convex portions
2Ease of manufacture
If a through hole is formed in the first forged article, then the ring material can be produced, but a large amount of material must be removed reducing production efficiency
Solution Approach 1:
The manufacturing process is divided into two stages: first forging to create a disc-like shape with peripheral wall, then drilling the bottom to form the through hole. This segmentation allows the bulk material removal to occur during the first forging stage when the material is more ductile and easier to shape, rather than removing large amounts of material from a solid cylinder
Solution Approach 2:
The first forging process preliminarily forms the disc-like shape and creates the peripheral wall structure before drilling. This preliminary shaping action reduces the amount of material that needs to be removed during drilling, as the peripheral wall already defines the future ring geometry, thereby improving production efficiency
3Manufacturing precision
If the peripheral wall is inclined at 7-40 degrees, then dead metal regions are reduced and near-net-shape forging is achieved, but the first forging process becomes more complex
Solution Approach 1:
The peripheral wall is designed with a specific inclination angle of 7-40 degrees relative to the vertical axis, creating an asymmetric geometry that directs material flow during the first forging process. This asymmetric shape prevents material from accumulating in dead metal regions at the corners, achieving near-net-shape forging that reduces the need for subsequent material removal and improves production efficiency
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 approach enables the reliable and efficient production of ring molded articles with reduced dead metal regions, improved mechanical characteristics, and effective convex formation, even when convex portions are offset, allowing for near-net-shape forging and enhanced mechanical strengths.
Implementation Method 1
In the second forging, strain is imparted to the ring molded article, the crystal grains which form the ring molded article, are thus refined, and thereby, mechanical strengths, such as a tensile strength and a fatigue strength, can be in particular improved
Implementation Method 2
a temperature of the surface region of the ring material which is in contact with the molds, is decreased in comparison with a temperature of a central region of the ring material according to influence from heat release to the mold which is primarily made of a metal
Data Source
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AI summary
A ring molded article manufacturing method capable of reliably and efficiently producing a ring molded article in which dead metal regions are reduced, is provided. In the present invention, a material is processed by first forging so as to be shaped in a shape including a bottom which is formed in a substantially disk shape, and a peripheral wall which is inclined to a direction from a center of the bottom toward an outer periphery thereof, in a direction from the outer periphery of the bottom toward one side in a direction of a center axis of the bottom, the bottom of a first forged article obtained by the first forging is drilled, a drilled article obtained by the drilling is ring-rolled, a ring material obtained by the ring rolling is placed inside two molds, the ring material is then processed by second forging so as to be pressed by the two molds in a direction of a center axis of the ring material, and the ring molded article is thus produced.