H-Shaped Steel Rolling With Raised Web for Wider Flanges
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Solution Overview
Problem
Current methods for producing large-size H-shaped steel products face limitations in broadening flange width due to device constraints and inefficiencies in flat shaping and rolling, leading to elongation and deformation issues, which affect the thickness and shape of the final product.
Innovation Solution
A method involving a rough rolling step with edging and flat rolling processes, utilizing calibers with recessed parts to form raised parts and sequentially bend flange parts, and adjusting the thickness and width of the web part to improve flange generation efficiency without causing elongation or deformation, using a specific formula to determine optimal web thickness based on the escaping percentage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flat shaping and rolling is performed to reduce web corresponding part, then web thickness is reduced, but web corresponding part elongates in longitudinal direction and flange corresponding part thickness decreases
Solution Approach 1:
The patent divides the web corresponding part into multiple regions: a reduced portion at each end and an unreduced portion (protruding part) in the middle. This segmentation allows selective reduction of web thickness at specific locations while preventing elongation in the longitudinal direction, thereby resolving the contradiction between achieving desired web thickness and avoiding unwanted elongation and flange thinning.
Solution Approach 2:
The patent applies different reduction characteristics to different parts of the web: the reduced portions undergo thickness reduction while the unreduced portion maintains its thickness. This local differentiation enables precise control over web thickness distribution and prevents the elongation and flange thinning that would occur with uniform reduction.
2Area of stationary object
If conventional rough rolling methods are used to broaden flanges, then width spread rate is about 0.8 initially but decreases to 0.5 with repeated edging, but flange width cannot be greatly increased due to device limits
Solution Approach 1:
The patent performs edging rolling before flat shaping and rolling to preliminarily broaden the flange width. By creating deep splits on the end surfaces of the raw material and bending the flange parts outward, the flange width is increased in advance, which compensates for the limited width spread rate during subsequent rolling operations and overcomes device constraints.
Solution Approach 2:
The patent transitions from conventional single-dimension rolling to a two-stage process involving edging rolling (creating splits and bending flanges outward) followed by flat shaping and rolling. This dimensional approach allows flange width to be increased by utilizing the width direction more effectively, achieving greater flange broadening than traditional rolling methods.
3Area of stationary object
If large-size raw material is used to increase edging amount, then flange broadening may be improved, but device limits in facility scale and reduction amount constrain the rough rolling mill
Solution Approach 1:
The patent performs edging rolling as a preliminary step before flat shaping and rolling in the rough rolling mill. By broadening the flange width in advance through edging, the subsequent rolling operations can work with smaller reduction amounts, thereby avoiding the need for oversized facility scale and large reduction amounts that would constrain the rough rolling mill.
Data Source
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AI summary
A large-size H-shaped steel product is efficiently and stably produced by performing flat shaping and rolling of a large-size raw blank while improving a generation efficiency of flanges without bringing about problems such as elongation in a web height direction and deformation of a flange corresponding part. A rough rolling step includes 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, a width of the raised part formed in the flat rolling step is set to 25% or more and 50% or less of a web part inner size of the material to be rolled, and a thickness of the web part rolled in the flat rolling step is set to a predetermined thickness thicker than a web part thickness when the intermediate rolling step is started.