Piercing-rolling plug arc-spraying film durability

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Solution Overview

Problem

Conventional piercing-rolling plugs with arc-sprayed films face durability issues when piercing long billets or high-temperature strength billets, leading to reduced production efficiency and plug lifespan.

Innovation Solution

A method using a system with multiple arc-spraying booths to divide the plug's surface into sections, allowing each booth to form the film separately, with spray guns operating within a controlled intersection angle of 35 to 90 degrees to enhance film adhesiveness and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single arc-spraying booth is used to form the film on the plug surface, then the equipment complexity is reduced, but the film formation time increases and production efficiency decreases

Engineering Contradiction:
Improveequipment complexityVSAvoidproduction efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The plug surface is divided into multiple sections along the axial direction, with each section sprayed by a separate arc-spraying booth. This segmentation allows parallel processing of different surface regions, reducing total film formation time while maintaining equipment manageability through modular booth design.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the spray gun operates at a small intersection angle, then the film formation speed increases, but the film adhesiveness to the plug surface deteriorates

Engineering Contradiction:
Improvefilm formation speedVSAvoidfilm adhesiveness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The intersection angle between the spray stream and plug surface is optimized to a specific range (35-90 degrees) to achieve the best balance between film formation speed and adhesiveness. This parameter optimization ensures that the molten material adheres properly to the shotblasted surface while maintaining efficient spray deposition.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If arc-spraying is performed in a vacuum environment, then the film purity and quality improve, but the equipment complexity and cost increase

Engineering Contradiction:
Improvefilm qualityVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Arc-spraying is performed in an air environment rather than vacuum, simplifying equipment requirements. The shotblasting process creates a rough surface that enhances mechanical interlocking of the sprayed film, providing adequate adhesiveness without requiring vacuum conditions. This approach maintains film quality while significantly reducing equipment complexity.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

4Manufacturing precision

If the plug is rotated at high speed during arc-spraying, then the film uniformity improves, but the centrifugal force reduces material deposition efficiency

Engineering Contradiction:
Improvefilm uniformityVSAvoidmaterial deposition efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The plug rotation speed is dynamically adjusted to an optimal range that balances film uniformity and deposition efficiency. The rotation provides sufficient centrifugal force to distribute material evenly across the surface while maintaining enough deposition rate to ensure efficient film formation. This dynamic optimization resolves the trade-off between uniformity and productivity.

Inventive Principle:
Principle #15Dynamics

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 maintains high production efficiency and significantly extends the durability life of the piercing-rolling plug, even with long or high-temperature billets, by ensuring strong adhesiveness and uniform film formation across the plug surface.

Implementation Method 1

an arc-spraying device for performing arc-spraying of iron wires on a shotblasted surface of a base metal of the plug

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 2

melting the iron wires by an arc, and spraying molten material thereof onto the surface of the base metal of the plug

Methodology Applied
Scientific EffectArc-spraying: Plasma Spray

Data Source

PatentEP2845657B1Method for producing a piercing plug
Publication Date: 2018.02.28 NIPPON STEEL & SUMITOMO METAL CORP
  • EP2845657B1 patent drawingFigure 1
  • EP2845657B1 patent drawingFigure 2
  • EP2845657B1 patent drawingFigure 3

AI summary

Provided is an equipment system for producing a piercing-rolling plug to be used for producing a seamless steel tube/pipe, which includes a shotblasting device for applying shotblasting on a surface of the plug, and an arc-spraying device for performing arc-spraying of iron wires on a surface of a base metal of the plug to which the shotblasting is applied, so as to form a film containing oxide and Fe thereon. The arc-spraying device includes plural spraying booths each of which separately forms part of the film in turn in each of sections into which the surface of the base metal of the plug is divided along an axial direction of the plug. The production efficiency of the plug can therefore be maintained at a high level, and steady enhancement of the durability life of the plug can be realized during the piercing-rolling.