Plug Base Metal Arc Spraying Film Peeling Prevention

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Solution Overview

Problem

Existing plug designs for piercing-rolling mills experience film peeling at connecting portions, particularly when handling high alloy steels, which reduces the plug's lifetime and efficiency.

Innovation Solution

A method involving a plug base metal with a concave portion along the circumferential direction, where the boundary between arc-sprayed regions is set at the concave portion, ensuring a slope difference that moderates surficial pressure and reduces film peeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If arc spraying is performed separately in each region of the plug surface, then the adhesiveness of the arc-sprayed film is improved, but film peeling occurs at the connecting portions between regions

Engineering Contradiction:
Improveadhesiveness of arc-sprayed filmVSAvoidintegrity of arc-sprayed film
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The plug surface is divided into multiple regions for separate arc spraying operations to improve film adhesiveness in each region, while the connecting portions are strategically positioned at concave portions where film peeling is suppressed

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The concave portions are specifically designed at connecting regions to create localized geometric features that moderate surficial pressure and prevent film peeling, while other regions maintain their specific spraying characteristics for optimal adhesiveness

Inventive Principle:
Principle #3Local quality

2Productivity

If the plug is used for piercing-rolling of high alloy steel, then the productivity is improved, but film peeling occurs more frequently reducing plug lifetime

Engineering Contradiction:
Improvepiercing-rolling efficiencyVSAvoidplug lifetime
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The concave portions are designed in advance at the connecting portions of the plug to moderate surficial pressure during high alloy steel piercing-rolling, preventing film peeling before it occurs and thereby extending plug lifetime while maintaining high productivity

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the boundary between arc-sprayed regions is set at the concave portion, then film peeling is suppressed, but the manufacturing complexity increases

Engineering Contradiction:
Improvefilm integrityVSAvoidplug manufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The concave portions are introduced only at specific connecting regions where film peeling occurs, rather than modifying the entire plug geometry. This localized approach suppresses film peeling while minimizing the increase in manufacturing complexity

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 approach effectively suppresses film peeling at connecting portions, increasing the plug's lifetime and maintaining the integrity of the arc-sprayed films during high-temperature piercing-rolling processes.

Implementation Method 1

an arc spraying step of spraying a spraying wire rod material onto the outer peripheral surface of the plug base metal by arc spraying to form films containing Fe and Fe oxides

Methodology Applied
Scientific EffectArc spraying: Arc Evaporation

Data Source

PatentEP3257596B1Method for producing plug
Publication Date: 2019.10.02 NIPPON STEEL CORPORATION
  • EP3257596B1 patent drawingFigure 1~2(c)
  • EP3257596B1 patent drawingFigure 3(a)~3(d)
  • EP3257596B1 patent drawingFigure 4(a)~5(b)

AI summary

A method for producing a plug includes: a step of preparing a plug base metal (10) having a concave portion (11z) along a circumferential direction in an outer peripheral surface (11); and an arc spraying step of spraying a spraying wire rod material onto the outer peripheral surface (11) of the plug base metal (10) by arc spraying to form films (20a and 20b) containing Fe and Fe oxides on the outer peripheral surface (11) of the plug base metal (10). The arc spraying step includes: a separating step of separating the outer peripheral surface (11) of the plug base metal (10) into a plurality of regions (S1 and S2) along an axial direction; and a step of performing arc spraying separately in each of the regions (S1 and S2). In the separating step, a boundary between the regions (S1 and S2) is set at the concave portion (11z). In this way, peeling of films at a connecting portion is prevented, and the lifetime of the plug can be increased.