Piercing Machine Plug Regeneration via Sprayed Film

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Solution Overview

Problem

The existing plugs used in piercing machines for manufacturing seamless steel pipes suffer from high melting loss and scoring due to the erosion of oxide scales, which limits their usage count and affects the quality of the hollow shells produced.

Innovation Solution

A regenerating method for plugs that includes a body with a columnar portion and a sprayed film, where the sprayed film is formed on the surface and the columnar portion, and the plug is cut to restore its original shape and size by shifting the rear end backward, allowing for the formation of a new sprayed film to enhance wear resistance and prevent scoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oxide scale is formed on the surface of the plug base metal to prevent melting loss, then the plug is protected from high temperature erosion, but the oxide scale is gradually reduced and worn away, causing the maximum diameter of the plug to decrease and limiting the usage count

Engineering Contradiction:
Improveprotection from melting lossVSAvoidmaximum diameter of the plug
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent changes the material parameter of the protective layer from oxide scale (formed by oxidation) to sprayed film (formed by thermal spray deposition). This parameter change allows the protective layer to be replenished without eroding the base metal, thus maintaining the plug's maximum diameter while continuing to protect against melting loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The sprayed film acts as an intermediary protective layer between the plug base metal and the high-temperature billet. Unlike oxide scale that erodes the base metal, the sprayed film can be applied as a separate coating that protects the underlying metal without requiring its removal or erosion.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of repair

If the plug is designed with a parallel portion to allow rearward shifting for regeneration, then the plug can be regenerated by cutting and shifting, but the oxide scale formation still causes gradual reduction of the maximum diameter, limiting the number of regeneration cycles

Engineering Contradiction:
Improveregeneration capabilityVSAvoidmaximum diameter of the plug
Core Design Contradiction:
Ease of repairVSLength of stationary object

Solution Approach 1:

The patent changes the protective layer formation method from oxidation (which erodes base metal) to thermal spray deposition (which adds material without eroding base metal). This allows multiple regeneration cycles through cutting and rearward shifting while maintaining the original maximum diameter of the plug body.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The sprayed film is formed on the columnar portion in advance before regeneration operations. When the plug needs regeneration, the film is removed along with the melted portion, and a new film is formed on the rearward-shifted columnar portion, restoring the plug to its original dimensions without cumulative diameter loss.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a sprayed film is formed on the surface of the plug to enhance wear resistance, then the plug is protected from scoring and melting, but the sprayed film needs to be removed and reapplied during regeneration, requiring additional processing steps

Engineering Contradiction:
Improvewear resistance and scoring preventionVSAvoidregeneration process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The columnar portion serves multiple functions: it provides material for regeneration by rearward shifting, and it serves as a substrate for the sprayed film. The sprayed film formation process is integrated into the existing regeneration workflow, where the film is applied to the columnar portion before each piercing operation, making the protective coating part of the standard preparation process rather than an additional step.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The method significantly enhances the usage count of the plugs by preventing wear and melting, maintaining the plug's size and shape, and ensuring the quality of the hollow shells produced during the piercing process.

Implementation Method 1

a sprayed film which is formed on the surface of the body, and on the surface of the columnar portion

Methodology Applied
Scientific EffectSpraying: Fluid Spray

Data Source

PatentEP2837434B1Plug used in piercing machine and plug regeneration method
Publication Date: 2018.01.17 NIPPON STEEL & SUMITOMO METAL CORP
  • EP2837434B1 patent drawingFigure 1~2
  • EP2837434B1 patent drawingFigure 3A~3B
  • EP2837434B1 patent drawingFigure 4

AI summary

It is an objective to provide a plug capable of enhancing a usage count of the plug, which is for use in a piercing machine for piercing-rolling a billet, and a regenerating method of the plug. The plug (10) is for use in a piercing machine (30) for piercing-rolling a billet (36). The plug (10) includes a body (18), a columnar portion (20), and a sprayed film (16). The body (18) has a maximum diameter at its rear end. The columnar portion (20) has the same diameter as the diameter of the rear end of the body (18), and extends from the rear end of the body (18). The sprayed film (16) is formed on a surface of the body (18) and on a surface of the columnar portion (20).