| Popis: |
The paper is concerned with the influence of selection of machine with optimal characteristics, and influence of heating metal sheets on the effects of energy management and environment protection. Bending force and calibration force in plate bending are very important. Calibration force is determined when bending force and calibration coefficient are known. Significant factors for determination of bending force for circular plate are: the material of the circular plate, bending radius of the circular plate, diameter of the circular plate, thickness of the circular plate and method of loading of the circular plate. The calibration coefficient is determined by experiment. Endothermic carburizing atmospheres consist of a mixture of carburizing agents (CO, CH4) and decarburizing (CO2, H2O) agents, the ratio of which determines the carburizing potential in the furnace. As the driving force for carburizing is determined by the gradient between the carbon potential in the atmosphere and carbon at the steel surface, it is imperative to maintain a high carburizing potential throughout the whole process. From a thermodynamic standpoint, the generation of the carburizing atmosphere is a complex process involving the interaction of numerous gases. Endothermic gas is most commonly produced by mixing air and natural gas and consists of CO, CO2, CH4, H2, H2O and N2. Among various chemical reactions occurring simultaneously in the carburizing atmosphere, only three reactions are important and determine the rate of carbon transfer. |
