CLADDING TECHNOLOGY SHANXI CO., LTDMetal-Based Ceramic Grinding Disc Liner Surface Cladding Bonding Study
Literature Overview and Technical Context
This 2022 study by Zhang Haiyan, Lu Xiaokai, Yang Wei, Wei Wei, and Gao Zhanqi from Zhengzhou Machinery Research Institute Co., Ltd. investigates the bonding characteristics of metal-based ceramic composite grinding disc liners produced through surface cladding techniques. The research is situated within the cement industry, where grinding mills process raw materials and clinker through high-energy mechanical action. The grinding discs and liners within these mills experience extreme abrasive wear, often exceeding 50 mm per month in wet grinding operations.
The concept of metal-based ceramic composite materials for grinding applications represents a significant evolution from traditional manganese steel liners. By embedding ceramic particles or ceramic layers within or upon a metallic matrix, the composite achieves both the toughness of the metal and the hardness of the ceramic, creating a material system that resists both abrasive and impact wear simultaneously.
Technical Approach and Material System
Material System Design
| Component | Material Specification | Function |
|---|---|---|
| Base substrate | Q345B or Q460 steel | Structural support |
| Bonding layer | Ni-Fe or Ni-Cr alloy | Metallurgical compatibility |
| Functional layer | WC-Co or Cr₂O₃-Al₂O₃ cermet | Abrasive resistance |
| Ceramic particles | SiC, Al₂O₃, or WC | Hard phase reinforcement |
| Matrix binder | Fe, Ni, or Co alloy | Toughness and bonding |
The bonding challenge in metal-ceramic composite cladding is fundamentally a materials compatibility problem. Ceramics exhibit coefficients of thermal expansion typically in the range of 5-9×10⁻⁶/K, while metallic matrices range from 10-18×10⁻⁶/K. This mismatch generates interfacial thermal stresses during cooling that can exceed the interfacial shear strength, leading to delamination.
Cladding Process Parameters
| Parameter | Specification | Impact on Bonding |
|---|---|---|
| Cladding method | PTA or laser cladding | Controls thermal gradient |
| Powder composition | WC-17Co-5Cr or modified | Dilution and microstructure |
| Powder size | 15-45 μm | Melting uniformity |
| Carriage speed | 200-400 mm/min | Heat input control |
| Wire/powder feed rate | 150-300 mm/min | Layer thickness control |
| Layer thickness | 0.5-1.5 mm per pass | Stress distribution |
| Number of layers | 3-5 layers | Cumulative dilution |
Bonding Mechanism Analysis
Interface Microstructure
The bonding quality between the ceramic-containing cladding layer and the metallic substrate is determined by several factors:
- Metallurgical bonding: At the atomic level, interdiffusion of metallic elements across the interface creates a gradient zone that provides mechanical interlocking and chemical bonding.
- Mechanical interlocking: The presence of ceramic particles creates a roughened interface that mechanically anchors the layers together.
- Thermodynamic compatibility: The formation of metallic carbides (Cr₇C₃, Cr₃C₂, Cr₂₃C₆) at the interface can either strengthen or weaken the bond depending on their distribution and morphology.
Dilution Effects on Bonding
Dilution is perhaps the most critical parameter affecting bonding quality in cermet cladding. When the cladding alloy melts and mixes with the substrate metal, the resulting microstructure differs significantly from the intended composition.
| Dilution Rate | Interface Character | Bond Strength | Wear Performance |
|---|---|---|---|
| <10% | Clean interface, minimal reaction | Excellent | Optimal |
| 10-20% | Moderate carbide formation | Good | Slightly reduced |
| 20-35% | Significant carbide network | Acceptable | Reduced hardness |
| >35% | Excessive dilution, loss of cermet character | Poor | Severe degradation |
The target dilution rate for WC-Co based cermet cladding is typically maintained below 20% through careful control of preheating temperature, number of layers, and the use of a transition bonding layer.
Quality Assessment and Testing Methods
Bond Strength Evaluation
| Test Method | Standard | Measurement | Pass Criteria |
|---|---|---|---|
| Shear test | ASTM B671 | MPa | >200 MPa |
| Peel test | ASTM G99 | N/mm | >150 N/mm |
| Impact test | Internal standard | Visual + UT | No delamination |
| Thermal cycling | Custom | Cycles to failure | >500 cycles |
Metallographic Examination
Microstructural analysis reveals that successful metal-ceramic cladding exhibits:
- A gradient transition zone at the interface with no sharp boundaries
- Uniform distribution of unmelted and partially melted WC particles within the matrix
- Absence of continuous crack networks along grain boundaries
- Hardness gradient from substrate (200-250 HV) through transition zone (400-600 HV) to functional layer (1200-1500 HV)
Engineering Practice and Performance
In cement grinding mill applications, the performance of cermet cladded liners is evaluated through:
- Service life extension: Typically 2-4 times that of conventional Mn13Cr2 manganese steel liners
- Grinding efficiency: 10-20% improvement due to maintained surface profile and reduced ball charge degradation
- Maintenance intervals: Extended from 3-6 months to 12-18 months depending on operating conditions
- Energy consumption: Reduced by 5-10% due to improved grinding efficiency
The FMEA analysis of potential failure modes reveals that the most critical risk is progressive delamination at the ceramic-metal interface under cyclic loading. This is mitigated by ensuring proper heat input during cladding, maintaining dilution within specification, and applying a post-weld heat treatment to relieve residual stresses.
Study Insights and Implications
The 2022 publication timing reflects the maturation of cermet cladding technology for industrial applications. The research demonstrates that the bonding problem, while fundamentally challenging, can be systematically addressed through material system design, process parameter optimization, and rigorous quality control. The transition from laboratory-scale development to industrial-scale application requires addressing issues of geometric complexity, throughput requirements, and cost-effectiveness that are not apparent in bench-scale studies. The work by the Zhengzhou Machinery Research Institute team contributes valuable data on the relationship between microstructure and macroscopic bonding performance that directly informs production quality standards.