| Aluminum alloy is widely used in various manufacturing industries,so its performance is very important,the harmful gas of hydrogen is the only large amounts of soluble in aluminum melt,easy to make the casting defects such as blowholes,shrinkage,thus reducing its performance.At present,the domestic and foreign furnace detection technology is numerous,mostly not to wait for the detection of hydrogen diffusion balance,but need to wait for a long time,is the need to use high cost probe advanced,greatly increasing its detection difficulty.Therefore,it is very important to study a kind of fast,low cost hydrogen measurement device on-line measurement,which is very important for degassing and hydrogen measurement of aluminum alloy.Based on the analysis of a variety of hydrogen measurement techniques at home and abroad,this paper summarizes the characteristics of hydrogen measurement technology and equipment,combined with the advantages and disadvantages of hydrogen measurement technology at home and abroad,developed a low-cost,Recovery rate of hydrogen method.The source and form of the hydrogen in molten aluminum alloy were analyzed and discussed.The process of hydrogen evolution in hydrogen melt and the process of dissolution and diffusion of hydrogen in molten alloy were described.The hydrogen bubble in aluminum alloy melt was introduced in detail.The mechanism of hydrogen evolution in the aluminum alloy melt was studied.Based on the principle of the negative pressure rising rate and the computer acquisition and control system,a hydrogen recovery device with negative pressure rising rate method was developed.Calibration system and test system two parts:Calibration system mainly includes the configuration of different hydrogen content of aluminum alloy melt and to achieve the establishment of aluminum alloy melt hydrogen partial pressure and negative pressure recovery rate of the database function.The test system is mainly used to measure the recovery rate of the partial pressure of hydrogen in the molten aluminum alloy,and then calculate the functionof the hydrogen content in the melt.Hydrogen measuring system is mainly composed of two parts of hardware and software,the hardware includes the gas control switch of vacuum pumps,vacuum solenoid valve manufacturing environment control,data acquisition and calculation analysis of solenoid valve switch relay,the computer system,the nonlinear transfer temperature and pressure sensor,vacuum chamber and buffer pipeline,gas diffusion environment and probe measuring device connected Aluminum Alloy melt;the part of the software program is compiled with the Delphi language,mainly through the program interface to achieve the opening and closing of the electromagnetic valve of the hydrogen system,so as to realize the conversion,calibration and measurement of hydrogen fusion distribution function,data acquisition and analysis of temperature and pressure sensors at the same time the real-time curve and the data form and displayed on the interface of the software,and finally display the results.Using the device for the different configuration of the alloy melt hydrogen content and aluminum alloy melt hydrogen content in the calibration of the corresponding relationship between negative pressure recovery rate,and the hydrogen content in aluminum alloy melt was tested.Test results show that the device has low cost,rapid measurement and the characteristics of the measuring accuracy,through the improvement and optimization to meet online test requirements. |
PDF Full Text Request