Research And Preparation Of The Wider Temperature Range Fe-based Solid Self-lubricating Composites Used By Metallurgical Facility

This paper analyzes its microstructure and organization through XRD and SEM, shows the tribological properties tested by SRV high temperature tribometer, and tells the mechanical properties of Fe-based solid self-lubricating composites with compound lubricant Ni coated graphite and calcium fluoride made through powder metallurgy technology. Based on the research of Fe-based alloy, the article gives the impacts on the mechanical properties and the tribological characteristics of Fe-based composites when Ni coated graphite and calcium fluoride were added respectively. With the research results, Fe-based self-lubricating composites can gain excellent comprehensive properties in a wider temperature range, to provide a better solution for the lubrication of metallurgical facility in extreme working conditions.(1) The mechanical properties are optimal when the graphite accounts for 0.9% of the composites with Fe-Ni-Cu-Mo as its matrix. The mechanical properties of the composites are preferable when sintered in the temperature range of 1200℃and 1220℃.(2) When adding Ni coated graphite, the mechanical properties and tribological characteristics of the composites are much more superior to the composites containing common graphite, which shows the graphite coated with Ni can avoid segregation and sintering loss and otherwise, therefor improving the mechanical properties and tribological characteristics. Based on Fe-Ni-Cu-Mo-0.9%graphite composites, with the increase of Ni coated graphite contents in the composites, the mechanical properties go down and friction coefficient decrease gradually. While the wear rate decrease at first and increase afterward. The wear rate is the lowest when Ni coated graphite accounts for 3.36% of the total.(3) In the composites with calcium fluoride, Ni, Cu, Mo and C completely solid dissolve into the material matrix. The calcium fluoride doesn't react with matrix in sintering process, and distribute evenly with graphite in the material matrix. With the increase of calcium fluoride contents, its mechanical properties fall gradually. In room temperature, the friction coefficient changes slightly and the wear rate rises continuously but slowly. At 500℃, the friction coefficient falls perpetually, while the wear rate decreases at first and increases then. The wear rate at 500℃is lower than that in room temperature in all cases. Composites gain excellent tribological characteristics in wider temperature range when calcium fluoride amounts to 5%. For the composites without calcium fluoride, the tribological properties decrease greatly with the temperature rise. While composites with calcium fluoride can keep the excellent tribological properties from room temperature to 500℃.(4) The practical applications in the steel plants show that the Fe-based solid self-lubrication composites made according to the technology introduced in this article have excellent anti-wear and anti-friction properties, a longer service life and lower costs. The compound materials can satisfy pyrometallurgical plants' needs on lubricating, and have already been applied in many steelworks.