Zhuojin Pipe Fitting Co., LtdWear-Resistant Surfacing Materials in Cement Industry Applications
Literature Overview
This review article by Wei Jianjun et al. (2009), published in China Surface Engineering (Vol. 22, No. 5), provides a comprehensive survey of wear-resistant surfacing technology applications in cement industry machinery. Authored by researchers at the Zhengzhou Mechanical Research Institute, the paper examines the operating conditions, failure modes, surfacing processes, materials, and application results for critical cement grinding and crushing equipment. The scope encompasses composite manufacturing and remanufacturing approaches for extending component service life.
Operating Conditions and Failure Mechanisms of Cement Equipment
Cement industry equipment operates under some of the most demanding tribological conditions in industrial manufacturing. The paper systematically analyzes the following critical components:
| Equipment Component | Operating Condition | Primary Failure Mode | Typical Service Life (Unsurfaced) |
|---|---|---|---|
| Squeeze rollers | High pressure, abrasive slurry, continuous rotation | Abrasive wear, surface fatigue | 3–6 months |
| Vertical mill rollers | Impact loading, abrasive cement clinker | Abrasive wear, spalling | 6–12 months |
| Grinding discs | Sliding contact with abrasive material | Abrasive wear, thermal fatigue | 4–8 months |
| Crusher hammers | Impact, abrasion, corrosion | Impact-abrasive wear, fracture | 2–5 months |
| Hammer discs | High-energy impact, abrasive wear | Impact-abrasive wear, fatigue cracking | 3–6 months |
The wear mechanisms in cement equipment are predominantly abrasive—both two-body and three-body abrasion—combined with impact loading and, in some cases, thermal cycling effects. The cement clinker and raw meal contain sharp angular particles with high hardness (frequently exceeding 600 HV), creating extremely aggressive wear conditions.
Surfacing Materials and Process Classification
The paper categorizes surfacing materials and processes based on the specific wear mechanism and equipment requirements:
Material Systems
| Material Type | Typical Composition | Hardness (HV) | Primary Application | Wear Mechanism Addressed |
|---|---|---|---|---|
| High-carbon martensitic | C 1.2–2.5%, Cr 8–12% | 500–700 | Squeeze rollers, grinding discs | Abrasive wear |
| Austenitic with carbides | Cr 20–30%, Ni 5–10% | 250–400 | Vertical mill rollers | Impact-abrasive wear |
| Ceramic-filled | Cr7C3, WC, TiC particles | 800–1200 | Crusher hammers, hammer discs | Severe abrasive wear |
| Hardfacing overlay | Ni-Cr-C, Co-Cr-C | 600–1000 | High-severity applications | Multi-mechanism wear |
Surfacing Processes
- Submerged arc surfacing (SAW): High deposition rate, suitable for thick overlay builds; commonly used for squeeze rollers and grinding discs
- Flux-cored wire arc surfacing (FCAW): Good process flexibility, moderate deposition rate; widely used in remanufacturing operations
- Electrode arc surfacing (SMAW): Portable, suitable for field repairs and complex geometries; used for crusher hammers and smaller components
- Plasma transfer arc surfacing (PTA): High dilution control, excellent composition accuracy; used for high-value components requiring precise microstructure
Composite Manufacturing and Remanufacturing Approaches
The paper distinguishes between two application strategies:
Composite Manufacturing: New components are manufactured with a base material optimized for toughness and fatigue resistance, with a wear-resistant surfacing layer applied to the wear surface. This approach achieves an optimal combination of core toughness and surface hardness that cannot be realized with a homogeneous material. For example, a vertical mill roller might have a low-carbon steel core (tensile strength 500–600 MPa, impact toughness >47 J at -20°C) with a high-chromium martensitic surfacing overlay (hardness 550–650 HV).
Remanufacturing: Worn components are restored through machining of the damaged surface followed by re-application of the surfacing layer. This approach is economically superior to replacement for high-value components such as vertical mill rollers and grinding discs, where the base material represents a significant portion of the total component cost.
Application Results and Economic Analysis
The paper reports that surfacing technology extends component service life by multiples—typically 2 to 5 times—compared to conventional manufacturing approaches. The economic benefits include:
- Reduced replacement frequency and associated downtime
- Lower energy consumption per unit of cement produced (due to maintained equipment efficiency)
- Reduced material waste and environmental impact from component manufacturing
- Extended useful life of expensive base materials through remanufacturing
Development Directions and Research Recommendations
The authors identify three key development directions for cement industry surfacing technology:
- Expansion of application scope: Apply existing proven surfacing solutions to additional equipment components that currently lack optimized surfacing specifications.
- Fundamental wear mechanism research: Develop deeper understanding of the specific wear mechanisms operating in different cement equipment to enable more targeted material and process selection.
- Balanced material development: Simultaneously optimize wear resistance and crack resistance—these two properties are often in conflict in high-carbon, high-hardness surfacing materials. Future materials must achieve high hardness without sacrificing the toughness needed to resist crack initiation and propagation under impact loading.
Engineering Practice Integration
For engineers working in cement plant maintenance and equipment engineering, this review provides a practical framework for surfacing specification development. The key decision factors are: the specific wear mechanism (abrasive, impact-abrasive, erosive), the allowable maximum dilution rate, the required minimum hardness, the acceptable maximum crack sensitivity, and the economic life-cycle cost including remanufacturing potential. The FMEA approach is particularly useful here—identifying the most probable failure modes for each component and selecting surfacing solutions that address the dominant failure mechanism while maintaining adequate resistance to secondary failure modes.
Study Insights and Reflections
This review, while published in 2009, remains relevant because it establishes a systematic framework for surfacing technology selection in cement applications. However, several areas warrant updated attention: the development of advanced ceramic-filled surfacing consumables with improved bonding characteristics, the application of laser cladding for thin, low-dilution overlays on precision-ground surfaces, and the integration of condition monitoring data with surfacing life prediction models. The fundamental principle remains unchanged: matching the surfacing material and process to the specific tribological environment is the key to maximizing component service life and economic efficiency. The paper's emphasis on balancing wear resistance with crack resistance is particularly prescient, as many field failures in cement equipment are not caused by uniform wear but by crack initiation and propagation in the surfacing layer under cyclic loading.