Investigations of Processes of Compacting of Tribotechnical Powder Materials Based on Dispersed-Strengthened Copper
DOI:
https://doi.org/10.20535/1810-0546.2015.6.72727Keywords:
Dispersed-strengthened copper, Current collector, Density, Hardness, Flexural strength, Specific electrical resistivity, Heating, Stamping, StructureAbstract
Background. Creation of theoretical and technological foundations of antifriction powder materials using dispersed-strengthened copper powders is urgent task, requiring a dependency determination of properties of the final product on the conditions of its receipt.
Objective. The purpose of this paper is to study the processes of obtaining products from powder materials based on dispersed-strengthened copper by hot stamping of current collector by electric vehicles. Determine the effect of parameters of stamping to form density, structure and some properties of the piece – hardness, flexural strength and specific electrical resistivity.
Methods. A processes research technique of products compacting from powder materials by hot stamping was proposed. Density, structure and properties research was conducted using modern techniques and equipment to study the mechanical properties, optical and electron microscopy, computer technology.
Results. Processes of compacting of antifriction materials of based dispersed-reinforced copper were investigated. Dependence of properties on the conditions of their production – stamping power, temperature and heating time of initial blanks before stamping was established. It was show that under certain conditions stamping density material greatly increases with the stamping power gain to 200 N×m/cm3 and herein after does not change much. Relative density of material heated to a temperature of 950 °С for 20–25 min is 99-100 %. Further increase in heating time leads to a decrease in density after stamping.The value of the hardness of the material correlates with the density. The maximum hardness is 550–600 MPa. The value of flexural strength and specific electrical resistivity also correlates with the density of the material, but also depends on the structure of the material. Maximum values of flexural strength is 180–200 MPa and minimum values of specific electrical resistance is 3.8–4.0 mOhm×cm. The results were explained using modern ideas about forming properties of powder materials when their compaction, which enables them to obtain predetermined properties.
Conclusions. Dependence of properties of antifriction materials by electric vehicles (current collector) from the conditions of their manufacture compacting porous hot stamped billets was established. Optimum conditions to obtain materials with maximum density, hardness, ultimate tensile strength and flexural specific minimum electrical output of billets are part blanks heated at the temperatures 900–950 °С for 15–20 min and their following stamping on specific energy of 200–250 N×m/cm3.
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