Forging Tool Curved Mandrels Prevent Ring Cracks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of turbomachine discs using nickel or nickel-chromium alloys is hindered by a narrow temperature window for forging, leading to rapid cooling and crack formation during rolling, necessitating multiple reheating steps and corrective machining to prevent defects.
Innovation Solution
A forging tool with two mandrels featuring curved connections between the bottom and lateral faces, with radii of curvature between 10 and 20 mm, which reduces the formation of sharp angles and prevents cracking by maintaining a continuous slope during the rolling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rolling tools with sharp angles are used, then the rolling process is simple and fast, but cracks appear in the rolled ring due to rapid cooling
Solution Approach 1:
The patent applies curvature by replacing the sharp angular connections between bottom and lateral faces with curved surfaces having radii of 10-20mm. This spherical/curved transition prevents stress concentration and thermal shock at corners, eliminating crack formation while maintaining tool functionality.
2Reliability
If multiple reheating steps are performed, then crack formation is prevented, but manufacturing time is greatly extended
Solution Approach 1:
The curved surface design is implemented in advance during tool manufacturing, so that during the actual rolling process, the curvature automatically prevents crack formation without requiring intermediate reheating operations. The preventive geometry eliminates the need for repeated thermal processing.
3Reliability
If corrective grinding is performed, then cracks are removed, but material is lost and additional time is consumed
Solution Approach 1:
The curved surface geometry applies preliminary anti-action by preventing crack formation in the first place through stress distribution and thermal management. This preventive approach eliminates the need for subsequent corrective grinding operations that would remove material.
4Strength
If the temperature window for forging is narrow, then alloy strength is increased, but the process becomes more difficult to control
Solution Approach 1:
The patent changes the geometric parameters of the tool (introducing curvature with specific radii of 10-20mm) to compensate for the narrow temperature window. This parameter change in tool geometry creates a more forgiving manufacturing process that maintains alloy strength while improving ease of manufacture.
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 solution effectively prevents crack formation during rolling without the need for reheating or manual machining, ensuring the quality of the forged rings and reducing manufacturing time.
Implementation Method 1
the bottom face of each of the mandrels is connected to the lateral faces by curved portions having radii of curvature of between 10 and 20 mm... these connections arrive in front of the curved portions, which squash the sharp angles and maintain the connections to radii of curvature
Data Source
AI summary
Mandrels for rolling a ring include recesses for receiving the ring, which have rounded parts at the connection between the various faces, so as to avoid the formation of sharp angles on the rolled ring and the accidental formation of cracks.