Continuous-Curvature Convex Roll for Crack-Reduced Bloom Casting
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Solution Overview
Problem
Existing metal casting technologies face issues with stress concentration and cracking due to singular points in the profile curve of convex rolls, leading to uneven deformation and increased rolling pressure during the continuous casting process.
Innovation Solution
A method for manufacturing a continuous curvature convex roll with a transition curve that ensures first-order, second-order derivative continuity and curvature continuity, reducing stress concentration and allowing for uniform deformation of the casting bloom while minimizing rolling pressure and withdrawal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a transition curve is formed using two arc curves to connect the protuberance and ends of the convex roll, then the transition between regions is achieved, but the curve contains singular points (tangent intersections) that create stress concentration and lead to cracking during rolling
Solution Approach 1:
The patent replaces the traditional two-arc curve transition with a cubic parabola curve (y = ax³ + bx²) that provides continuous first and second derivatives throughout the transition zone. This eliminates singular points and tangent intersections, creating a truly smooth transition that prevents stress concentration and cracking during the rolling process.
2Shape
If the projection length of the transition curve on the x-axis is increased to ensure proper connection between arcs, then the transition is more gradual, but the straight line sections at both ends of the protuberance become shorter, increasing rolling pressure and withdrawal resistance
Solution Approach 1:
The patent uses a cubic parabola equation (y = ax³ + bx²) with optimizable coefficients a and b to control the transition curve shape. By adjusting these parameters, the invention achieves a balance between transition gradualness and maintaining adequate straight line section lengths, thereby reducing both rolling pressure and withdrawal resistance while ensuring smooth deformation.
Data Source
Figure 1~2
AI summary
Disclosed are a continuous-curvature convex roll for continuously casting a bloom, and a manufacturing method therefore, belonging to the field of metal casting. An outer contour curve of a working portion of a body of the continuous-curvature convex roll consists of a first straight-line segment (AB), a first transition curve segment (BC), a intermediate straight-line segment (CD), a second transition curve segment (DE) and a second straight-line segment (EF). The first transition curve segment (BC), the first straight-line segment (AB), and the intermediate straight-line segment (CD) have continuous first-order derivatives, continuous second-order derivatives, and continuous curvatures, thus forming a first transition curve with a continuous curvature. The first transition curve segment (BC) and the second transition curve segment (DE) are mirror-symmetrical. The continuous-curvature convex roll manufactured according to the technical solution 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. The present invention can be widely used in the field of metal casting.