Research And Development Of Temperature Control System For Magnesium Alloy Melting Furnace

As the lightest commercial metallic structure material at present, magnesium alloy was widely used in automobile, motorcycle, IT, aerospace industries etc. because of its distinguish characteristics. As a result of the increasing demand on magnesium alloy, vital productive facilities like magnesium alloy melting furnace and die-casting machine are attracting more and more attentions. However, for now there are only a few industrially advanced countries have fully-developed technology to produce these equipments. A few institutes and firms are capable of producing the furnace though, performances are far behind. Under this circumstance, the Science and Technology Department of Zhejiang Province's project, Research and Development of Eco-friendly Mg Alloy Re-melting Technique & Quantitative Pouring Furnace was proposed. This paper focuses on the research and development of temperature control system for magnesium alloy melting furnace.Functional demand for temperature control system was confirmed according to the thorough analysis on entire system of magnesium alloy melting furnace. Based on the analysis on the technical procedure of magnesium alloy melting a proper heat rate was calculated and the melt temperature fluctuation pattern was studied, via computer simulation on thermal conductivity and thermal stress of the crucible during heating-up procedure.Then a system design scheme consists by PID algorithm control strategy and multiple point temperature detect was then adopted to stabilize improper heating rate and to narrow melt temperature fluctuation during pouring procedure.A control system consisted by a PC and PLC was designed in demand of temperature control. PLC is used to automatically control heating rate and gather data. On the other hand, the PC performs as the user's interface. The monitor software which connects the host computer and PLC and controls the whole system was developed in Visual Basic 6.0. Therefore, human operation was simplified, failure rate was reduced and the system's precision and flexibility was increased.After software and hardware design, aluminum melting experiments were conducted to test the performance of the temperature control system. The feasibility of heating system, the hybrid control strategy using PID control and duty cycle output control was proved rational. Magnesium heating control experiments were performed on an experimental furnace system which was built based on the results from aluminum melting experiments. It can be concluded from results of magnesium melting experiments that the temperature control system designed and developed in this research has achieved the expected targets and the project's quest in the present stage has been completed.