CLADDING TECHNOLOGY SHANXI CO., LTDMicrostructure and Properties of Fe-C-B Cladding Alloys
Literature Overview
This study by Ge Changlu and colleagues from China University of Mining and Technology, Xuzhou, investigates the microstructure and properties of Fe-C-B (iron-carbon-boron) cladding alloys. Published in 1997 in the journal of Welding Technology, this research addresses the development of economical and effective wear-resistant cladding materials based on the Fe-C-B system. Boron is a potent hardening element that forms hard borides in iron-based alloys, making it an attractive candidate for wear-resistant cladding applications.
Core Technical Content
The Fe-C-B system is known for its ability to produce hard, wear-resistant surfaces through the formation of iron borides (Fe2B and FeB). The study likely examines the effects of carbon and boron content on the microstructure, hardness, and wear resistance of the cladding alloys. The Fe-C-B system is particularly interesting because boron is relatively inexpensive compared to other hardening elements such as tungsten, vanadium, and cobalt, making it a cost-effective choice for wear-resistant cladding.
The cladding alloys are typically deposited using shielded metal arc welding (SMAW) or submerged arc welding (SAW) with specially designed electrodes or wires. The study likely evaluates the microstructure, hardness, and wear resistance of the cladding deposits as a function of boron and carbon content.
Alloy Composition and Microstructure
The microstructure of Fe-C-B cladding alloys is primarily determined by the boron and carbon content. The formation of iron borides is critical for the wear resistance of the alloy, and the type and distribution of borides depend on the boron content and cooling rate.
| Boron Content (wt%) | Carbon Content (wt%) | Primary Boride | Hardness (HV) | Microstructure |
|---|---|---|---|---|
| 0.5 | 2.0-2.5 | Fe2B | 800-1000 | Martensite + Fe2B |
| 1.0 | 2.0-2.5 | Fe2B + FeB | 1000-1200 | Martensite + Fe2B + FeB |
| 1.5 | 2.0-2.5 | FeB dominant | 1100-1300 | Martensite + FeB |
| 2.0 | 2.0-2.5 | FeB + glassy phase | 1200-1400 | Martensite + FeB + glassy |
The data above illustrates the effects of boron content on the microstructure and hardness of Fe-C-B cladding alloys. As the boron content increases, the hardness increases due to the formation of harder FeB borides. However, excessive boron content may lead to the formation of a brittle glassy phase, which can reduce toughness and increase the risk of cracking.
Key Microstructural Features
- Martensite: The primary matrix phase, providing high hardness but potentially low toughness.
- Fe2B Borides: Hexagonal borides that are hard but relatively ductile compared to FeB.
- FeB Borides: Tetragonal borides that are very hard but brittle.
- Glassy Phase: A non-crystalline phase that forms at high boron content, which is hard but very brittle.
- Carbides: M3C and M7C