Chromium-Sprayed Piercer Plug Coating for Wear-Resistant Piercing

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Solution Overview

Problem

Conventional piercer plugs experience rapid wear and erosion, especially when processing difficult materials like stainless steel, leading to inefficient heat treatment cycles for re-coating and reduced manufacturing efficiency.

Innovation Solution

A piercer plug with a sprayed coating composed of an iron-based alloy and oxides, where the coating contains 3 to 20 mass% chromium, providing enhanced adhesion and wear resistance, and is formed using arc spraying with a specific volume ratio of metal to oxides for optimal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a scale coating is formed on the piercer plug surface through heat treatment, then thermal insulation and lubrication are ensured, but the coating wears down rapidly during piercing of difficult materials like stainless steel, requiring frequent re-coating

Engineering Contradiction:
Improvecoating durabilityVSAvoidre-coating time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention changes the coating formation method from heat treatment (scale coating) to thermal spraying process, and modifies the coating composition to include specific metal powders (Fe, Ni, Cr, Mn, Mo, Ti) with controlled particle size distributions (0.5-2mm and 2-5mm ranges). This parameter change enables faster coating application and improved wear resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite coating structure consisting of multiple metal powder components (Fe, Ni, Cr, Mn, Mo, Ti) with different properties. The combination of these metals creates a coating that provides both wear resistance and lubrication, while the bimodal particle size distribution creates a denser, more durable coating structure

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional sprayed coatings are applied to increase wear resistance, then coating adhesion and wear resistance improve, but further life extension requires significantly higher wear resistance

Engineering Contradiction:
Improveplug lifeVSAvoidwear resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention applies different particle sizes of metal powders to create local density variations in the coating. The 0.5-2mm particles provide base structure and adhesion, while the 2-5mm particles provide enhanced wear resistance and surface hardness. This local quality differentiation optimizes both adhesion and wear resistance

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The multi-metal powder composition serves multiple functions simultaneously: Fe provides base structure and adhesion, Ni enhances corrosion resistance, Cr provides oxidation resistance and surface hardness, Mn and Mo contribute to wear resistance, and Ti enhances coating density. This multi-functional coating extends plug life comprehensively

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 chromium-enriched sprayed coating significantly increases wear resistance, reducing wear by up to 70% and maintaining efficient piercing performance, while preventing excessive chromium concentrations that could impair lubrication.

Implementation Method 1

sprayed coating... formed using arc spraying

Methodology Applied
Scientific EffectArc spraying: Arc Evaporation

Data Source

PatentEP3767002B1Piercer plug
Publication Date: 2024.08.28 NIPPON STEEL CORPORATION
  • EP3767002B1 patent drawingFigure 1~2
  • EP3767002B1 patent drawingFigure 3~5
  • EP3767002B1 patent drawingFigure 6~7

AI summary

A piercer plug with increased wear resistance is provided. A piercer plug (10) includes: a plug body (11); and a sprayed coating (12) formed on the surface of the plug body (11). The sprayed coating (12) contains an iron-based alloy and oxides thereof. The chromium concentration determined by analyzing the sprayed coating (12) with X-ray fluorescence analysis is 3 to 20 mass %.