CLADDING TECHNOLOGY SHANXI CO., LTDResearch on Anti-Wear and Heat-Resistant Weld Overlay Electrodes
Literature Overview
This 2004 publication from the School of Materials Science and Engineering at Hefei University of Technology presents research on the development of specialized hardfacing electrodes designed for combined anti-wear and heat-resistant performance. The study addresses a critical need in industrial applications where components are simultaneously subjected to abrasive wear and elevated operating temperatures, such as in cement kilns, steel mill guides, furnace linings, and high-temperature material handling equipment.
Electrode Design Philosophy and Composition
The development of a single electrode system that provides both wear resistance and heat resistance requires careful balancing of competing metallurgical requirements. High-carbon martensitic systems offer excellent room-temperature hardness but suffer from rapid softening above 400°C, while austenitic and ferritic systems maintain strength at elevated temperatures but typically exhibit lower room-temperature hardness.
Electrode Composition Design
| Element | Content (wt%) | Role |
|---|---|---|
| C | 2.5–3.5 | Primary hardening element, forms carbides |
| Cr | 12–18 | Carbide formation, oxidation resistance |
| Mo | 2–5 | Reduces softening temperature, secondary hardening |
| V | 1–3 | Fine carbide precipitation, wear resistance |
| W | 1–4 | High-temperature strength, carbide stability |
| Ni | 0–3 | Stabilizes austenite, improves toughness |
| Mn | 1.5–3.0 | Deoxidizer, grain refinement |
| Fe | Balance | Base matrix |
Mechanical Properties Comparison
| Electrode Type | Hardness (HRC) at 25°C | Hardness at 400°C (HRC) | Hardness at 600°C (HRC) | Retained Hardness Ratio |
|---|---|---|---|---|
| Conventional high-C martensitic | 58–62 | 35–40 | 15–20 | 0.30–0.35 |
| Cr-Mo-V-W composite carbide type | 55–60 | 45–50 | 30–35 | 0.55–0.60 |
| Austenitic with precipitates | 40–45 | 38–42 | 30–33 | 0.70–0.75 |
| Base metal (45 steel) | 25–28 | 15–18 | 10–12 | 0.40–0.45 |
Microstructural Analysis and Wear Mechanisms
The optimized electrode composition produces a microstructure consisting of:
- Matrix: Mixture of martensite and retained austenite, providing base toughness
- Primary carbides: Cr7C3, Mo2C, WC, and VC distributed throughout the deposit
- Secondary carbides: Fine precipitates of Cr23C6 and Fe3C in the intercellular regions
- Carbide network: Interconnected carbide phases providing load-bearing framework
The wear resistance mechanism operates through multiple synergistic pathways: the hard carbide particles resist abrasive penetration, the metallic matrix accommodates plastic deformation around the particles, and the retained austenite provides strain-induced hardening during contact loading.
Application Performance and Service Experience
| Application | Service Temperature | Wear Life Improvement | Electrode Type |
|---|---|---|---|
| Cement kiln roller | 200–400°C | 4–6× | Cr-Mo-V composite |
| Steel mill guide bar | 300–500°C | 5–8× | Cr-Mo-W type |
| Furnace charge bucket | 400–600°C | 3–5× | Austenitic with precipitates |
| Coal mill grinding ring | 150–250°C | 6–10× | High-C martensitic |
| Hydraulic press guide | 100–200°C | 5–7× | Cr-Mo-V type |
Study Insights and Practical Implications
The research demonstrates that the development of combined anti-wear and heat-resistant electrodes requires a systems approach to composition design, moving beyond simple carbon content optimization to incorporate multi-element carbide systems. The inclusion of molybdenum, vanadium, and tungsten in combination with chromium creates a hierarchical carbide structure that maintains hardness at elevated temperatures through secondary hardening mechanisms. For engineering practice, the selection between electrode types should be guided by the actual service temperature rather than room-temperature hardness alone. An electrode with 55 HRC room-temperature hardness that retains 35 HRC at 600°C will outperform an electrode with 62 HRC at room temperature that drops to 20 HRC at the same temperature. The study also highlights the importance of welding procedure control: the interpass temperature must be maintained between 200–300°C to prevent over-tempering of the previous pass while avoiding cold cracking, and the number of passes should be limited to maintain the designed carbide distribution. This work provides a valuable foundation for the continued development of specialized overlay systems for extreme service environments in heavy industry.