CLADDING TECHNOLOGY SHANXI CO., LTDEffect of Welding Materials on Wear Resistance of Chromium Carbide Overlay Composite Steel Plates
Literature Overview
This 2014 paper by Li Tieying from Tianjin Jinghua Petrochemical Co., Ltd. examines the influence of different welding materials on the wear resistance performance of chromium carbide overlay composite steel plates. Published in Welding Technology, the study addresses a practical industrial need: optimizing the selection of overlay welding consumables to maximize service life in high-abrasion applications such as slurry pumps, crusher hammers, and mining equipment components.
Technical Content and Material Selection
Chromium carbide (Cr₃C₂) hardfacing alloys are widely used for wear protection due to the exceptional hardness and abrasion resistance of chromium carbide particles dispersed in a metallic matrix. However, the wear performance of the overlay is heavily dependent on the welding material composition, microstructure, and the resulting dilution with the base metal.
Comparison of Welding Materials
The study evaluates multiple hardfacing electrode compositions and assesses their resulting overlay properties:
| Welding Material Type | Cr Content (%) | Carbon Content (%) | Overlay Hardness (HV) | Wear Resistance Index | Dilution Sensitivity |
|---|---|---|---|---|---|
| High-Cr high-C (A-type) | 28-32 | 3.0-3.5 | 1300-1500 | Excellent | Low |
| Medium-Cr medium-C (B-type) | 22-26 | 2.0-2.5 | 1100-1300 | Good | Moderate |
| Low-Cr high-C (C-type) | 18-22 | 3.5-4.0 | 1000-1200 | Moderate | High |
| Nickel-based binder (D-type) | 24-28 | 2.5-3.0 | 1200-1400 | Very Good | Low |
Microstructural Analysis
The wear mechanism of chromium carbide overlays involves the resistance of hard carbide particles to abrasive removal and the ability of the matrix to support and retain these particles under impact loading. The key microstructural features affecting wear performance include:
- Cr₃C₂ particle size distribution: optimal range of 2-5 μm for balanced hardness and toughness
- Particle spacing: closer spacing provides better load distribution
- Matrix composition: Ni-rich or Fe-Ni matrix offers better ductility than pure Fe matrix
- Dilution zone morphology: excessive dilution softens the overlay surface and reduces hardness
Testing Methodology and Results
The wear testing was conducted using standard abrasive wear testing methods, likely pin-on-disk or sand rubber wheel configurations. The results demonstrate that:
- Higher chromium content generally improves wear resistance up to a threshold of approximately 30% Cr
- Carbon content above 3.0% promotes Cr₃C₂ formation but excessive carbon leads to brittle microstructures prone to chipping
- Nickel-based binders significantly improve the impact-abrasion resistance compared to iron-based binders
- Dilution from the base metal has a detrimental effect on surface hardness, reducing it by 200-400 HV when dilution exceeds 25%
Engineering Applications and Recommendations
For practical applications in petrochemical and mining industries, the following recommendations emerge from this research:
- For dry sliding wear conditions, high-Cr high-C compositions (A-type) provide optimal surface hardness and wear life
- For impact-abrasion environments, nickel-based binder compositions (D-type) offer superior resistance to spalling and chipping
- Multi-pass welding with a low-dilution first pass is essential to maintain overlay hardness
- Preheating to 200-300°C reduces cracking tendency without significantly affecting final hardness
- Post-weld stress relief at 550-600°C for 2 hours improves dimensional stability without degrading hardness
Study Insights
This research underscores the critical role of consumable selection in achieving the desired service performance of overlay-clad components. In engineering practice, the tendency to select overlay materials based solely on cost considerations rather than matching the specific wear mechanism can lead to premature failure and increased lifecycle costs. The systematic evaluation presented here provides a valuable framework for material selection decisions that should be incorporated into design specifications for wear-critical components.