CLADDING TECHNOLOGY SHANXI CO., LTDDesign of Iron-based High-temperature Wear-resistant Welding Electrodes
Literature Overview
The paper by Liu Zhengjun, Li Yongkui, Chen Hong, Liu Chen, and Wang Chunzhi from the School of Materials Science and Engineering at Shenyang University of Technology, published in the Journal of Shenyang University of Technology in 2004, addresses the design and development of iron-based welding electrodes specifically formulated for high-temperature wear resistance. This work sits at the intersection of welding consumable metallurgy and tribology, targeting industrial applications where components are subjected simultaneously to elevated temperatures and abrasive or adhesive wear conditions. The authors systematically explored the relationship between alloy composition, microstructural evolution, and the resulting wear performance under thermal loading.
Core Technical Content
The fundamental challenge addressed in this work is the degradation of conventional wear-resistant overlay layers at elevated service temperatures. At temperatures exceeding 400 degrees Celsius, the hardness of standard martensitic or austenitic overlay deposits decreases significantly due to tempering, carbide coarsening, and phase transformations. The authors identified that the key to achieving sustained wear resistance at high temperature lies in the formation of thermally stable carbides and the maintenance of a fine, hard microstructure even after prolonged thermal exposure.
The research team designed multiple electrode formulations based on an iron-nickel-cobalt matrix with strategic additions of chromium, tungsten, molybdenum, and vanadium. These alloying elements were selected to promote the formation of complex carbides such as M7C3, M2C, and MC types, which retain their hardness at temperatures well above 500 degrees Celsius. The electrode coating composition was carefully balanced to ensure good weldability, crack resistance, and a stable arc during deposition.
| Design Parameter | Typical Range | Purpose |
|---|---|---|
| Cr content | 8-14 wt% | Promotes M7C3 and M23C6 carbide formation |
| Mo content | 2-5 wt% | Enhances solid solution strengthening and thermal stability |
| W content | 1-3 wt% | Forms hard WC and W2C carbides |
| V content | 1-3 wt% | Produces fine, thermally stable MC carbides |
| Ni content | 3-8 wt% | Improves ductility and reduces cracking tendency |
| C content | 2.5-4.0 wt% | Ensures sufficient carbide volume fraction |
Microstructural Analysis and Wear Mechanisms
The authors conducted metallographic examinations of the deposited overlay layers and identified a matrix of retained austenite and tempered martensite, with a high volume fraction of dispersed carbide particles. At room temperature, the overlay layer exhibited hardness values in the range of 58-65 HRC. After heat treatment at 500 degrees Celsius for two hours, the hardness remained above 50 HRC, demonstrating excellent thermal stability compared to conventional high-carbon martensitic electrodes which typically drop to 35-40 HRC under the same conditions.
The wear resistance was evaluated using a pin-on-disk tribometer at both ambient and elevated temperatures. The results indicated that the designed electrodes achieved a wear rate reduction of 40-60 percent compared to standard high-chromium white iron overlay electrodes at temperatures above 400 degrees Celsius. The improved performance was attributed to the presence of fine, thermally stable MC and M2C carbides that resisted coarsening during thermal cycling, as well as the retained austenite in the matrix which provided a transformation-toughening mechanism under impact loading.
Engineering Practice Insights
From a practical standpoint, the findings of this research have direct implications for the selection and application of overlay welding consumables in industries such as cement manufacturing, power generation, and metallurgical processing, where components such as mill liners, kiln refractories, and turbine blades operate under combined thermal and wear conditions. The electrode design principles outlined by the authors emphasize that a holistic approach to composition design is necessary, balancing hardness, thermal stability, and weldability.
One critical observation from the study is that excessive carbon content, while beneficial for carbide formation, increases the risk of hot cracking in the deposited weld metal. The authors recommended a two-layer welding strategy, where a transition layer with lower carbon and higher nickel content is deposited first to reduce cracking susceptibility, followed by the high-carbon wear-resistant layer. This approach is consistent with established practices in weld overlay technology and underscores the importance of process design alongside consumable selection.
Study Reflections
This paper, though published in 2004, remains relevant due to the fundamental nature of the metallurgical principles it explores. The systematic approach to electrode design, combining thermodynamic calculations with experimental validation, sets a methodological example for subsequent research in wear-resistant consumables. The emphasis on thermal stability of carbide phases is particularly important for modern applications in renewable energy and advanced manufacturing, where operating temperatures continue to rise. The work also highlights the need for standardized testing protocols for high-temperature wear performance, as results obtained under different test conditions can be difficult to compare directly.