H-Shaped Steel Rough Rolling for Wide Flanges Without Deformation
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Solution Overview
Problem
Current methods for producing large-size H-shaped steel products with wide flanges face limitations in flange width expansion during the rough rolling process, leading to elongation and deformation issues, and insufficient broadening due to device constraints, resulting in inefficient production and defective shapes.
Innovation Solution
A method involving a rough rolling process with specific caliber configurations, including edging and flat rolling steps, where the width of the raised part in the flat rolling step is set between 25% and 50% of the web part's inner size, and the web thickness is adjusted to improve flange generation efficiency without causing elongation or deformation, using a 300 thick slab as raw material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional flat shaping and rolling is performed to reduce web thickness, then web reduction is achieved, but web and flange elongation occurs causing shape deformation
Solution Approach 1:
The patent divides the web reduction process into two separate stages: first reducing only the web portion while maintaining flange dimensions, then subsequently reducing the flange thickness. This segmentation prevents the simultaneous elongation of both web and flange that occurs in conventional flat shaping, thereby maintaining shape accuracy while achieving the desired thickness reductions.
Solution Approach 2:
The patent performs web reduction as a preliminary action before flange reduction. By first reducing the web thickness while keeping flanges at their original dimensions, the method prevents flange elongation that would occur if flat shaping were applied directly. This preliminary web reduction prepares the material for subsequent flange reduction without causing shape deformation.
2Area of stationary object
If edging rolling is repeated to broaden flanges, then flange width increases, but width spread rate decreases and device limits are reached
Solution Approach 1:
The patent performs edging rolling as a preliminary action during the rough rolling stage to create initial splits and broaden the flange width before the material enters the finishing rolling mill. This preliminary flange broadening reduces the subsequent edging required in the finishing stage, thereby maintaining higher width spread rates and avoiding device limits.
Solution Approach 2:
The patent segments the flange broadening process into two phases: initial edging during rough rolling to create splits and increase flange width, followed by elimination of splits in subsequent calibers. This segmentation allows significant flange width increase early in the process when the width spread rate is highest, before device constraints become limiting.
Data Source
AI summary
A large-size H-shaped steel product is produced by performing a rough rolling step including an edging rolling step of rolling and shaping a material to be rolled into a predetermined almost dog-bone shape, and a flat rolling step of performing rolling of a web part by rotating the material to be rolled after completion of the edging rolling step by 90° or 270°, upper and lower caliber rolls of at least one caliber of calibers configured to perform the flat rolling step include recessed parts configured to form a raised part at a middle of a web part of the material to be rolled, the recessed parts being provided at roll barrel length middle parts of the upper and lower caliber rolls.