Ring Rolling Material Pre-Shaping for Uniform Distortion
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Solution Overview
Problem
In ring rolling processes for high-temperature applications, such as gas turbines, abnormal heating can lead to degradation of product quality due to excessive temperature, resulting in coarse grains and reduced fatigue characteristics, and conventional methods face challenges in achieving uniform distortion across the material surface.
Innovation Solution
A manufacturing method involving heating a disk-shaped material, arranging it on a lower die with a convex truncated conical shape, forming a thin portion using an upper die with a matching convex shape, and shaping the material to include a height reducing portion that gradually reduces towards the inner peripheral surface, ensuring the center of gravity is closer to the outer surface, thereby controlling temperature and distortion uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hot forging and ring rolling methods are used, then production efficiency is maintained, but abnormal heating occurs causing coarse grain growth and degraded product quality
Solution Approach 1:
The material is pre-shaped into a blank with a specific geometry (circular section with diameter 0.8-1.2 times the final ring diameter) before ring rolling. This preliminary shaping creates optimal conditions for uniform distortion distribution during subsequent ring rolling, preventing localized abnormal heating and grain coarsening while maintaining efficient production
Solution Approach 2:
The invention changes the geometric parameters of the starting material from conventional disk or rectangular shapes to a specific circular section blank with controlled diameter ratio. This parameter change ensures uniform heat distribution and distortion during ring rolling, eliminating the technical contradiction between quality and productivity
2Manufacturing precision
If uniform distortion is achieved across the material surface, then fine grain structure is obtained, but conventional die forging creates dead zones with insufficient distortion
Solution Approach 1:
The material is pre-shaped into a circular section blank before ring rolling. This preliminary action ensures that the subsequent ring rolling process can apply uniform distortion across the entire material surface, eliminating dead zones where insufficient distortion would occur with conventional die forging
Solution Approach 2:
Instead of attempting to achieve uniform distortion through complex die forging (which creates dead zones), the invention inverts the approach by using simple ring rolling on a pre-shaped circular blank. This reverses the conventional sequence and achieves the desired uniform distortion more effectively
3Temperature
If multiple heating processes are used to prevent abnormal heating, then temperature control is improved, but the number of process steps and labor increase
Solution Approach 1:
The material is pre-heated and pre-shaped into a circular section blank before ring rolling. This preliminary heating, combined with the optimized geometry, allows the subsequent ring rolling to proceed with uniform temperature distribution, eliminating the need for multiple intermittent heating processes and reducing process complexity
Solution Approach 2:
The invention changes the geometric parameters of the material (circular section with specific diameter ratio) which fundamentally alters the thermal and mechanical behavior during ring rolling. This parameter change enables single-stage temperature control instead of multiple heating cycles, resolving the contradiction between temperature control and process complexity
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 suppresses abnormal heating, reduces grain growth, and achieves a high-quality ring with fine grains across the entire portion, enhancing fatigue characteristics and production efficiency by maintaining appropriate temperature ranges during ring rolling.
Implementation Method 1
heating a disk-shaped material for hot forging to a hot working temperature
Implementation Method 2
forming a thin portion by pressing a center portion of the material for hot forging by using an upper die having a convex portion with a truncated conical shape
Implementation Method 3
forming a thin portion by pressing a center portion of the material for hot forging
Data Source
AI summary
A manufacturing method provides a high-quality material for ring rolling. The manufacturing method of the material for ring rolling includes a step of heating a disk-shaped material for hot forging to a hot working temperature, a step of arranging the material for hot forging onto a lower die having a convex portion with a truncated conical shape, a step of forming a thin portion by pressing a center portion of the material for hot forging by using an upper die having a convex portion with a truncated conical shape, and a step of manufacturing a material for ring rolling by removing the thin portion, and in this method, a center of gravity on a half section of the material for ring rolling is located so as to be closer to an outer peripheral surface of the half section than a center of the half section in a thickness direction of the half section, a shape of the half section includes a height reduction portion having a height from a center line which divides the half section into halves in a height direction of the half section is gradually reduced toward the inner peripheral surface, and the shape thereof is formed in a substantially linearly symmetry so as to define the center line as a symmetrical axis of the half section, and the height of the inner peripheral surface is from 20% to 50% of a maximum height of the material for ring rolling.