An accurate prediction of the core losses is crucial for the optimal design and selection of the electrical steels used in electrical devices. The measured specific core losses are divided into three main parts, i.e., the eddy-current loss, the hysteresis loss, and the excess loss. In this paper, a simplified, predictive model for the core loss in a non-oriented electrical steel using fixed coefficients is proposed. The coefficients for a wide frequency spectrum up to 10 000 Hz of validity for the prediction of the eddy current, the hysteresis, and the excess components were calculated with respect to a sinusoidal voltage using the modified Steinmetz equation and a polynomial regression analysis.
COBISS.SI-ID: 1142954
In the manufacturing industry of electrical contacts, the prohibition of the use of toxic metals (Cd, Be), and desire to avoid the alloying with precious metals (Ag) has created a need for new alloys with good conductivity and high mechanical properties at elevated temperatures. As a potentially useful material for this purpose, we have analyzed the continuously cast Cu-Fe-Ni-P alloy in various heat treatment conditions. Sequence of phase transformations during heat treatment was followed by 4 point D.C. electrical resistivity measuring method and analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Measurements of Vickers hardness and electrical conductivity after various heat treatment procedures indicate on high potential of Cu-Fe-Ni-P alloys as a material for electrical contacts.
COBISS.SI-ID: 1507167
An experimental study was carried out on cold worked Cu-12.7 wt.% Au alloy and pure copper, in order to compare the properties change during thermo-mechanical treatment. Hardness, microhardness, and electrical conductivity were studied as a function of annealing temperature and annealing time with the purpose of investigating the intensity of anneal hardening effect in cold worked Cu-12.7 wt.% Au alloy. Isochronal (up to 350 °C) and isothermal (at 250 °C for 100 h) annealing of cold worked alloy caused a two-stage increase in all of the measured properties. The mechanism responsible for this increase was analyzed using DTA, XRD, and TEM studies. A substantial improvement in mechanical properties after cold rolling with 60% reduction and low temperature annealing of Cu-12.7 wt.% Au alloy was attributed to the comparative effects of short-range ordering and the reactions between solute atoms and lattice defects during the occurrence of anneal hardening.
COBISS.SI-ID: 1575007
The occurrence and formation sequence of secondary ledeburite in the heat affected zone of chromium ledeburitic tool steel W.Nr. 1.2379 (OCR12 VM) after welding with SAW, TIG, microplasma and laser welding techniques is presented. Special attention was paid on the behaviour of carbides. The occurrence of secondary ledeburite is a result local enrichment of the austenite matrix with alloying elements, due to partial or complete dissolution of primary/eutectic carbides. The results show that the largest amount of secondary ledeburite is formed during submerged arc welding, followed by TIG and microplasma welding technique. Welding by laser technique, with appropriate technological parameters, could prevent secondary ledeburite formation.
COBISS.SI-ID: 1108726
Lately, greater emphasis is placed on the quality of environment and rational resources management, and above all on energy sources, it being the basis of the quality of human life and sustainable development. The sustainable development of an organization is monitored through the organization’s performance being the result of its strategy that beforehand incorporated all stakeholders’ requirements. Although great number of companies apply strategic management concept and business success measurement methods, researches show that only every tenth company manages to implement defined strategy. The main causes of unsuccessful strategy implementation can be recognized in the lack of adequate strategic control mechanisms. The paper presents the methodology developed with an aim to eliminate the main deficiencies of the successful implementation of defined strategy and the monitoring of an enterprise's effectiveness.
COBISS.SI-ID: 1577311