Research And Design On The Device For Fast Measuring Hydrogen Content In Molten Aluminum Alloy

At present, with the development of modern science and technology and the demand increase of aluminum castings, more and more attention is paid to the improvement of aluminum alloy quality. It has very important significance to fast measure hydrogen content in front of furnace.In this paper, factors related to the porosity in aluminum castings have been analyzed, and the methods and the equipment of testing hydrogen content directly have been discussed in detail. A new portable instrument of fast testing hydrogen content in aluminum alloy has been designed by author on the basis of analyzing the principle of direct pressure diffusion method that has the merits of simple testing device, fast measurement and high accuracy and so on.The testing instrument is mainly composed of detector, vacuum unit, data acquisition and processing unit and so on. The quality of detector has great effect on the testing results, consequently, some requires must be met strictly that it has high strength, high heat resistance, considerable permeability. Besides, the aluminum alloy liquid can not react with detector and not permeate through it. The materials of making detector have been determined by experiments, namely, quartz sand is basic material, boracic acid is pore forming material and bentonite is adhesive. The method and craft of making detector is as follows. All materials blended in proportion are pressed to form rough and the rough is sintered at high temperature. Root pump is used to fast vacuumize in vacuum chamber and the data acquisition and processing unit is made up of the expanding unit based on MCS51 single chip microcomputer,the analog signals regulating unit, A/D converting unit and son on, which can carry the function of acquiring real time pressure and temperature. To improve the converting precision two-integrator conversion chip ICL7135 is adopted and all main program and subroutines of this instrument are programmed by the compile language.After primarily debugging in lab, the new portable instrument of fast testing hydrogen content in aluminum alloy can run successfully and carry out simulation test.