Laser-Surfaced Abradable Coating for Wear-Resistant Metal Parts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for surfacing or resurfacing metal parts in extruders and similar machinery fail to provide a durable, abrasion-resistant coating that maintains mechanical strength and prevents overheating, leading to reduced service life due to issues like over-tempering and poor attachment of coatings.
Innovation Solution
A process involving laser-assisted deposition of a filler material with a specific elemental composition (C0.3-2.5Si1.5-3.0B0.1-3.5Ni3.5-5.5Cr10-17V10-17.5Fe>50%) and a mixture of iron-based melt metal powder and refractory ceramic powder, using a Nd:YAG laser with operational wavelengths between 900 nm to 1100 nm, specific energy from 5 J/mg to 10 J/mg, and linear density from 25 mg/mm to 55 mg/mm to create an abradable coating with uniform hardness and minimal heat-affected zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser-assisted deposition is used to create a hard coating, then wear resistance is improved, but the substrate temperature rises causing over-tempering and loss of mechanical strength
Solution Approach 1:
The invention changes the laser processing parameters (energy density, pulse duration, scanning speed) to control the thermal input to the substrate. By optimizing these parameters, the coating is deposited with sufficient wear resistance while limiting the heat-affected zone depth to prevent over-tempering of the substrate below 2mm, thus maintaining mechanical strength.
Solution Approach 2:
The invention uses a composite coating material comprising hard refractory particles (such as tungsten carbide, boron carbide, or silicon carbide) embedded in a metal matrix. This composite structure provides the wear resistance of the hard particles while the metal matrix bonds to the substrate and dissipates heat, preventing excessive temperature rise and over-tempering.
2Strength
If heat-sprayed coating is used to avoid substrate temperature rise, then mechanical strength is maintained, but coating attachment is reduced due to mechanical anchoring only
Solution Approach 1:
The invention uses laser-assisted deposition with controlled energy parameters that melt the coating material and partially melt the substrate surface, creating a metallurgical bond. This thermal bonding mechanism provides superior coating attachment compared to mechanical anchoring alone, while the parameters are controlled to limit heat penetration and maintain substrate mechanical strength.
3Strength
If superficial surface-hardening is applied to increase hardness, then surface hardness is improved, but the hard layer thickness is too small for extrusion applications
Solution Approach 1:
The invention applies a preparatory step of depositing a thick layer of coating material containing hard refractory particles onto the substrate before final laser processing. This preliminary coating layer provides sufficient thickness for extrusion applications, and the subsequent laser treatment consolidates and hardens the surface while maintaining the required thickness.
Solution Approach 2:
The invention creates a composite coating with a metal matrix and dispersed hard refractory particles (such as tungsten carbide, boron carbide, or silicon carbide). This composite structure provides both the required thickness for extrusion applications and the surface hardness needed to resist wear from elastomer contact and abrasive fillers.
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 process results in a coating with an average hardness greater than 750 HV0.2, providing excellent wear resistance and uniform microstructure, while maintaining the mechanical properties of the substrate with a thin heat-affected zone, thus extending the service life of the metal parts.
Implementation Method 1
irradiation of the part by a laser beam such that the specific energy (SE) varies from 5 J/mg to 10 J/mg
Implementation Method 2
laser-assisted deposition of a filler material in order to produce an abradable coating
Data Source
AI summary
A subject of the invention is a process for surfacing or resurfacing a metal part by laser-assisted deposition of a filler material in order to produce an abradable coating of the part, the process being characterized in that the filler material is an iron-based powder comprising vanadium, chromium, nickel, boron, silicon and carbon, in that the laser has an operational wavelength ranging from 900 nm to 1100 nm and in that it comprises the irradiation of the part by a laser beam such that the specific energy (SE) varies from 5 J/mg to 10 J/mg and such that the linear density (LD) varies from 25 mg/mm to 55 mg/mm. Another subject of the invention is the surfaced or resurfaced metal part. Another subject of the invention is a pre-alloy in iron-based powder form, comprising vanadium, chromium, nickel, boron, silicon and carbon.