Spiral Rolling of Superalloy Bars for Uniform Ultrafine Grains
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Solution Overview
Problem
Current methods for producing ultrafine grained superalloy bars, such as SPD techniques like HPT, ECAP, ARB, MF, and TE, face limitations in forming load, material utilization, production efficiency, and grain refinement, particularly in producing larger-sized products with uniform grain size.
Innovation Solution
A rolling machine with quasi-circular truncated cone rollers and guide plates is designed to create a deformation zone with controlled ovality, allowing for the processing of superalloy blanks with diameters up to 500 mm and lengths of 300-15000 mm, using a spiral feeding mechanism and specific temperature and rotational parameters to achieve uniform deformation and grain refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ECAP method is used for ultrafine grain preparation, then grain refinement effect is improved, but forming load increases and product size is limited
Solution Approach 1:
The deformation process is segmented into multiple passes through the ECAP die, with each pass contributing to cumulative strain. The blank is processed in sequential stages rather than attempting single-pass deformation of large dimensions, enabling gradual grain refinement while managing forming load.
Solution Approach 2:
The invention transitions from conventional 2D cross-sectional deformation to 3D spiral path deformation through the ECAP die. The blank follows a helical trajectory within the deformation zone, utilizing the third dimension (spiral path length) to achieve cumulative strain without requiring excessive single-pass forming load.
2Manufacturing precision
If ECAP method is used for ultrafine grain preparation, then grain refinement effect is improved, but material utilization rate decreases
Solution Approach 1:
The ECAP die design with optimized deformation zone geometry serves multiple functions: it provides uniform triaxial stress state for grain refinement, accommodates various blank sizes through the spiral path, and minimizes material loss by maintaining full contact without excessive friction. This multi-functional design improves both grain uniformity and material utilization.
3Manufacturing precision
If HPT method is used for ultrafine grain preparation, then grain refinement effect is improved, but product thickness is limited to ultra-thin range
Solution Approach 1:
The invention replaces the conventional HPT mechanical system (which uses hydraulic presses with limited capacity) with a mechanical ECAP system using hardened steel dies. This substitution enables processing of thicker blanks (up to 100mm) by distributing the deformation load across the spiral path and die geometry, rather than concentrating it in a single compression zone.
4Force
If MF and TE methods are used for ultrafine grain preparation, then forming load is reduced, but grain refinement effect and deformation zone effectiveness decrease
Solution Approach 1:
The invention optimizes key parameters including the ECAP die angle (90°), the spiral path geometry, and the number of passes. These parameter changes create an optimized balance between forming load and grain refinement effectiveness, achieving uniform ultrafine grains while maintaining manageable deformation forces through the controlled spiral deformation path.
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
The method enables the production of ultrafine-grained superalloy bars with improved material utilization, production efficiency, and uniform grain size, reducing lateral spread deformation and tensile stress, while enhancing the grain refinement effect and surface quality.
Implementation Method 1
Severe plastic deformation (SPD) is a conventional process for the preparation of ultrafine grain/nano materials in the field of materials science
Implementation Method 2
heating the superalloy blank and introducing the heated superalloy blank from a gap between two first rollers of the rolling machine to the deformation zone
Implementation Method 3
cooling the superalloy blank
Data Source
AI summary
A method for preparing an ultrafine-grained superalloy bar, the method including: 1) designing a rolling machine including two rollers and two guide plates, where each of the two rollers includes a first roller and a second roller; the first roller includes a first curve and the second roller includes a second curve; the first curve and the second curve form a generatrix of the two rollers; 2) disposing the two guide plates with two curved surfaces thereof opposite to each other; disposing the two rollers to be between the two guide plates; where the two rollers and the two guide plates form a deformation zone of the rolling machine; and 3) driving the two rollers to rotate around their central axes, heating and introducing a superalloy blank from a gap between two first rollers to the deformation zone of the rolling machine; advancing the superalloy blank towards two second rollers.