Steel Plate Edge Bending with Offset Die Loading for Uniform Pipe Forming

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Solution Overview

Problem

Conventional edge bending methods for steel plates result in non-uniform bending shapes along the longitudinal direction, leading to defective welding and pipe shape issues, especially with high-strength steel plates, and require additional facilities for continuous bending.

Innovation Solution

An edge bending method using a pair of dies with a flat part and a transition part, where the flat part's center is displaced relative to the pressing force's center, allowing for uniform edge bending across the steel plate's length without introducing new facilities, by intermittently conveying the steel plate and adjusting the position of the leading and trailing ends during the bending process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If edge bending is performed several times by intermittently feeding the steel plate, then the entire length can be bent, but the bending shape varies in the longitudinal direction

Engineering Contradiction:
Improveeffective length of diesVSAvoiduniformity of bending shape
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by positioning the steel plate at specific intervals before each bending operation. The leading end position and trailing end position are predetermined based on the die length and plate thickness, ensuring that each intermittent bending operation contributes uniformly to the overall bending shape. This preliminary positioning prevents variation in bending shape that would otherwise occur during multiple intermittent operations.

Inventive Principle:
Principle #10Preliminary action

2Length of moving object

If the steel plate is longer than the effective length of the dies, then the plate can be processed, but single pressing cannot cover the entire length

Engineering Contradiction:
Improvelength of steel plateVSAvoidnumber of bending operations
Core Design Contradiction:
Length of moving objectVSProductivity

Solution Approach 1:

The patent ensures continuity of useful action by optimizing the intermittent feeding distance and bending parameters so that each bending operation overlaps slightly with the previous one. The leading end position and trailing end position are calculated to ensure continuous coverage of the entire plate length, eliminating gaps and reducing the total number of operations needed to achieve complete edge bending.

Inventive Principle:
Principle #20Continuity of useful action

3Strength

If edge bending is performed multiple times on high-strength steel plates, then the edges can be bent, but the bending shape becomes non-uniform

Engineering Contradiction:
Improvestrength of steel plateVSAvoiduniformity of bending shape
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies local quality by adjusting the bending parameters specifically for high-strength steel plates. The leading end position and trailing end position are determined based on the plate thickness and material properties, creating locally optimized bending conditions for each segment of the plate. This ensures uniform bending shape even when processing high-strength materials that require multiple intermittent operations.

Inventive Principle:
Principle #3Local quality

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 reduces the variation in edge bending deformation, ensuring consistent pipe shape and preventing defects in welding, while maintaining the same level of edge bending quality without the need for new equipment.

Implementation Method 1

a steel plate is arranged between a lower die and an upper die that has a curvature depending on a pipe diameter, and the lower die is lifted by a hydraulic cylinder such that the widthwise edges of the steel plate are pressed against the upper die

Methodology Applied
Scientific EffectHydraulic press: Hydraulic Press

Implementation Method 2

one of the pair of dies that contacts a surface positioned at the outer side of edge bending of the widthwise edge of the steel plate to be bent has a flat part that contacts the surface positioned at the outer side of edge bending

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3778050B1Method and device for bending edge of steel plate, and steel pipe manufacturing method and equipment
Publication Date: 2024.05.01 JFE STEEL CORP
  • EP3778050B1 patent drawingFigure 1
  • EP3778050B1 patent drawingFigure 2
  • EP3778050B1 patent drawingFigure 3

AI summary

Proposed an edge bending method in which bending of widthwise edges Sc and Sd of a steel plate S is performed several times by a pair of dies 23 and 24 while the steel plate S is intermittently conveyed by a conveyance mechanism 21 such that the widthwise edges Sc and Sd of the steel plate S are subjected to edge bending across an entire length. The lower die 24 that contacts a surface positioned at the outer side of edge bending of the widthwise edges Sc and Sd of the steel plate S to be bent between the pair of dies 23 and 24 has a flat part 24a that contacts the surface positioned at the outer side of edge bending, and edge bending is performed on the widthwise edges Sc and Sd of the steel plate S with a center C1 of the flat part 24a in the conveyance direction 1 being displaced to a delivery side 3 in the conveyance direction 1 relative to a center C2 of the pressing force P generated by the actuator in the conveyance direction 1.