Hat-Shaped Steel Sheet Pile Rolling With Hot Bending Shape Control

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Solution Overview

Problem

The existing production methods for hat-shaped steel sheet piles face inefficiencies in reducing production costs, improving yield, and stabilizing caliber multiple-pass rolling due to limitations in roll strength and temperature control, leading to issues like flange waves, twists, and reduced productivity.

Innovation Solution

A production method involving rolling in intermediate to finish rolling with a single caliber stand and on-line bending forming to achieve the desired height, while preventing flange waves and twists, and optimizing roll gaps to maintain accurate shaping and reduce material thickness variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If caliber multiple-pass rolling is performed to achieve desired shape, then manufacturing precision is improved, but device complexity increases due to limited roll strength and temperature control issues

Engineering Contradiction:
Improveshape accuracyVSAvoidrolling process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The rolling process is divided into rough rolling, intermediate rolling, and finish rolling stages, each with specific caliber configurations. The intermediate rolling mill performs multiple passes with calibers having different inclination angles to progressively achieve the desired hat-shaped cross-section, breaking down the complex shaping task into manageable segments

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The caliber inclination angles are dynamically adjusted during the rolling process. Intermediate rolling calibers have different inclination angles for different passes, allowing the process to adapt to changing material properties and temperature conditions, optimizing shape control at each stage

Inventive Principle:
Principle #15Dynamics

2Productivity

If the number of calibers is reduced to improve productivity, then production efficiency is improved, but manufacturing precision deteriorates due to insufficient shaping control

Engineering Contradiction:
Improveproduction efficiencyVSAvoidshape accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The rolling process operates continuously through coordinated rough rolling, intermediate rolling, and finish rolling mills. Material flows continuously through the process without interruption, and each rolling mill operates in sequence to progressively refine the shape, maintaining high productivity while ensuring precision through continuous shaping action

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

Different regions of the material cross-section are subjected to different rolling conditions. Intermediate rolling calibers are designed with specific inclination angles that apply localized deformation to specific areas of the material, achieving uniform shape control across the entire cross-section while maintaining efficient production

Inventive Principle:
Principle #3Local quality

3Loss of time

If rolling reduction per pass is increased to reduce the number of passes, then production time is reduced, but manufacturing precision deteriorates due to flange waves and twists

Engineering Contradiction:
Improverolling timeVSAvoidshape accuracy
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

Rough rolling performs preliminary shaping to reduce the cross-sectional dimensions of the rectangular material before intermediate rolling begins. This preliminary reduction prepares the material for subsequent precise shaping operations, allowing intermediate rolling to focus on achieving the final hat-shaped geometry with smaller, more controlled reduction per pass

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The rolling process uses periodic action through multiple passes with alternating caliber configurations. Intermediate rolling performs multiple passes with calibers having different inclination angles, applying periodic deformation cycles that progressively refine the shape while preventing defects like flange waves and twists through controlled, repeated shaping actions

Inventive Principle:
Principle #19Periodic action

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

This method enhances production efficiency, reduces rolling time and costs, and stabilizes caliber multiple-pass rolling, resulting in improved yield and product quality with reduced springback and material quality deterioration.

Implementation Method 1

a rectangular material, for example, is first heated to a predetermined temperature by a heating furnace

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a rough rolling mill including a pair of double rolls configuring a caliber is used to produce a raw blank

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP4098379B1Production method for hat-shaped steel pile
Publication Date: 2024.05.01 NIPPON STEEL CORPORATION
  • EP4098379B1 patent drawingFigure 1~2(f)
  • EP4098379B1 patent drawingFigure 3~4
  • EP4098379B1 patent drawingFigure 5

AI summary

There is provided a production method for a hat-shaped steel sheet pile including performing rough rolling, intermediate rolling, and finish rolling on a material to be rolled through hot rolling, and then performing bending forming, in which the material to be rolled is composed of a web corresponding part, flange corresponding parts, arm corresponding parts, and joint corresponding parts, corner parts as worked parts are formed at connection places between the web corresponding part and the flange corresponding parts and connection places between the flange corresponding parts and the arm corresponding parts, the intermediate rolling is carried out by performing rolling in a plurality of passes on the material to be rolled in a hot state by using a caliber provided to upper and lower caliber rolls in one or a plurality of intermediate rolling mills in which one stand is configured by one caliber, at a height lower than a predetermined target product height, the bending forming is performed in a hot state and performed in a state where the worked parts have a temperature of transformation point or higher, and in the bending forming, the material to be rolled is formed to have predetermined target height and target width.