Continuous-Curvature Convex Roll to Reduce Casting Stress Concentration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing convex rolls in metal casting exhibit stress concentration points due to non-smooth profile curves, leading to cracking and increased rolling pressure and withdrawal resistance during the deformation of continuous casting slabs.
Innovation Solution
A continuous curvature convex roll is manufactured with a profile curve featuring first-order derivative continuity, second-order derivative continuity, and curvature continuity, utilizing a method that includes forming transition curves with continuous curvature to reduce stress concentration and optimize deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If transition curves are formed using two arc curves to connect straight line sections, then the profile curve achieves first-order derivative continuity, but the curve contains singular points (stress concentration points) and does not achieve true smoothness
Solution Approach 1:
The patent replaces the traditional two-arc curve transition with a cubic parabola curve for the transition sections BC and DE. This curved design eliminates the singular points and stress concentration issues inherent in arc-based transitions, achieving true smoothness (continuous curvature) throughout the profile curve while maintaining the required geometric constraints for roll function.
2Manufacturing precision
If the projection length of transition curves is increased to achieve smooth connection, then curvature continuity is improved, but the straight line sections at both ends become shorter, increasing rolling pressure and withdrawal resistance
Solution Approach 1:
The patent optimizes the geometric parameters of the cubic parabola transition curves, specifically setting the projection lengths of transition curves BC and DE to 40mm each, and the intermediate straight line section CD to 150mm. This parameter optimization achieves curvature continuity while maintaining adequate straight line section lengths to control rolling pressure and withdrawal resistance within acceptable ranges.
3Manufacturing precision
If the convex roll applies heavy reduction to increase center density, then the internal quality of cast material is improved, but the deformation resistance from solidified shells increases cracking risk
Solution Approach 1:
The patent designs the convex roll with a protuberance height of 20mm concentrated at the center section, creating localized high-pressure zones that target the center region for density improvement. The smooth cubic parabola transition curves ensure that this concentrated reduction force is applied without creating stress concentration points that would initiate cracks in the solidified shells.
4Manufacturing precision
If the convex roll protuberance width is increased to cover loose segregation area, then the uniformity of cast material is improved, but the contact area increases rolling pressure
Solution Approach 1:
The patent optimizes the protuberance width parameter to 100mm, which is sufficient to cover the loose segregation area in the center of the casting bloom and improve material uniformity. This width is carefully balanced to avoid excessive contact area that would increase rolling pressure beyond acceptable limits.
Data Source
AI summary
Disclosed are a continuous-curvature convex roll for continuously casting a bloom, and a manufacturing method therefore. An outer contour curve of a working portion of a body of the continuous-curvature convex roll contains a first straight-line segment (AB), a first transition curve segment (BC), an intermediate straight-line segment (CD), a second transition curve segment (DE) and a second straight-line segment (EF). The BC, the AB, and the CD have continuous first-order derivatives, continuous second-order derivatives, and continuous curvatures, thus forming a first transition curve with a continuous curvature. The BC and the DE are mirror-symmetrical. The continuous-curvature convex roll can uniformly deform a blank cast in a deformation area, thereby reducing cracks. The transition curve of the convex roll can be reduced, thereby being capable of further reducing a rolling pressure and the withdrawal resistance.