Extensive analysis of the ETP grade copper wire drawing force parameters in correlation with the length of the elastic deformation region

Wire drawing process is generally known as the most recognized metal forming process, however, elastic deformations present during the process before entering the drawing die are mostly omitted. That is why the extensive experimental study of the process have been conducted using drawing dies of various geometry. It allowed to define the length of elastic deformation region and its influence on the recorded drawing force parameters which are closely related to drawing stresses and thus the safety factor of the process

Defects analysis of copper wires manufactured in industrial conditions

Many factors are responsible for the formation of surface and internal defects during copper wire drawing process. Generally they may be divided into defects of material or processing origin. Even input material of the highest quality with little to none defects cannot ensure the absence of breakages during the process due to inadequate process parameters. Optimally selected process parameters may reduce the risk of cracks forming during the metal forming process. The paper presents examples of wire defects and cracks occurring throughout the wire drawing process of copper in industrial conditions and a wide analysis of their source

Defects analysis of copper wires manufactured in industrial conditions

Many factors are responsible for the formation of surface and internal defects during copper wire drawing process. Generally they may be divided into defects of material or processing origin. Even input material of the highest quality with little to none defects cannot ensure the absence of breakages during the process due to inadequate process parameters. Optimally selected process parameters may reduce the risk of cracks forming during the metal forming process. The paper presents examples of wire defects and cracks occurring throughout the wire drawing process of copper in industrial conditions and a wide analysis of their source

Geometry and surface quality of the crystallization system and their influence on the temperatures throughout the continuous casting processes of copper-magnesium alloys

Copper-based materials for electrical purposes usually find their origin in continuous casting lines where the effectiveness of the process and the quality of the final product depends among others on the crystallization system. The paper investigates the influence of the surface quality of the crystallizer and the geometry of the cooling system on the temperature distribution throughout the copper-magnesium alloys casting process. The obtained results prove that as the contact between the crystallizer and the cooling system is worsening the temperature of the crystallizer and the cast rod increase significantly, therefore affecting the efficiency of the process

Susceptibility to deep processing in the wire drawing process of ETP and OF grade copper

The susceptibility to deep processing in the industrial wire drawing process has been investigated in the research paper regarding the copper grade influence on the process. The conducted research included the identification of the mechanical and electrical properties of wires manufactured from Electrolytic Tough Pitch Copper (Cu-ETP) wire rod and Oxygen-Free Copper (Cu-OF) cast rod in terms of the applied deformation. In particular, as main contribution of this research to the scientific and industrial community a mathematical model describing the wire strengthening and softening characteristics was determined

Susceptibility to deep processing in the wire drawing process of ETP and OF grade copper

The susceptibility to deep processing in the industrial wire drawing process has been investigated in the research paper regarding the copper grade influence on the process. The conducted research included the identification of the mechanical and electrical properties of wires manufactured from Electrolytic Tough Pitch Copper (Cu-ETP) wire rod and Oxygen-Free Copper (Cu-OF) cast rod in terms of the applied deformation. In particular, as main contribution of this research to the scientific and industrial community a mathematical model describing the wire strengthening and softening characteristics was determined

Characterisation of Cu-CNTs composite electrical properties in elevated temperatures

The current trend towards nanotechnology creates possibilities for its use in materials science as manufacturing material with extraordinary properties, and is one of the goals for scientists in this field. Carbon nanotubes in particular are promising due to their electrical, thermal and mechanical properties, which have been of interest for researchers around the world. This paper focuses on the manufacturing process of the Cu-CNT composite via powder metallurgy and KOBO extrusion process, its further cold drawing process, and electrical resistance test at an elevated temperature. As obtained data proved, the higher the CNT content the lower the electrical resistance

Power cycling analysis of enameled aluminium winding wires connections pprepared with the use of SHARK-Al® type connectors

The article presents the research results of current cyclic thermal tests performed on enamelled aluminium wires connections, made with the use of a new type of Shark-Al quick-connectors. In particular, the main purpose of the conducted research was to analyse the effect of cyclic heating on the contact resistance change during the tests which allows to test the stability of the connections in simulated working conditions under current flow. Tests included a total of 300 thermal cycles, of which the first 200 were carried out to the 65 °C temperature measured in the connector at above the ambient temperature, and then additional 100 cycles were performed for the temperature of the connector at 140 °C (tolerance +5 °C). During the tests, the resistance of samples was monitored, which allowed to verify the correctness of performed connections

Power cycling analysis of enameled aluminium winding wires connections pprepared with the use of SHARK-Al® type connectors

The article presents the research results of current cyclic thermal tests performed on enamelled aluminium wires connections, made with the use of a new type of Shark-Al quick-connectors. In particular, the main purpose of the conducted research was to analyse the effect of cyclic heating on the contact resistance change during the tests which allows to test the stability of the connections in simulated working conditions under current flow. Tests included a total of 300 thermal cycles, of which the first 200 were carried out to the 65 °C temperature measured in the connector at above the ambient temperature, and then additional 100 cycles were performed for the temperature of the connector at 140 °C (tolerance +5 °C). During the tests, the resistance of samples was monitored, which allowed to verify the correctness of performed connections

Spt6 is a maintenance factor for centromeric CENP-A

Replication and transcription of genomic DNA requires partial disassembly of nucleosomes to allow progression of polymerases. This presents both an opportunity to remodel the underlying chromatin and a danger of losing epigenetic information. Centromeric transcription is required for stable incorporation of the centromere-specific histone dCENP-A in M/G1 phase, which depends on the eviction of previously deposited H3/H3.3-placeholder nucleosomes. Here we demonstrate that the histone chaperone and transcription elongation factor Spt6 spatially and temporarily coincides with centromeric transcription and prevents the loss of old CENP-A nucleosomes in both Drosophila and human cells. Spt6 binds directly to dCENP-A and dCENP-A mutants carrying phosphomimetic residues alleviate this association. Retention of phosphomimetic dCENP-A mutants is reduced relative to wildtype, while non-phosphorylatable dCENP-A retention is increased and accumulates at the centromere. We conclude that Spt6 acts as a conserved CENP-A maintenance factor that ensures long-term stability of epigenetic centromere identity during transcription-mediated chromatin remodeling