Alloy Density Sensor Float Fiber Bragg Grating Melted

Density as one of the parameters of a variety of important physical properties of the material, its measurement is widely used in the field of modem defense, metallurgical industry, precision casting process design is critical to the understanding of the thermophysical properties of metallic materials. Such as Tin refining, the density of Pb-Sn molten alloy and the smelting temperature can be detected as molten binary alloy of Pb-Sn component key basis. Density parameters of the pure metals are generally well documented, and for various kinds of metal alloy, however, not directly from the literature Richard, the need for actual measurement in order to obtain accurate data. A conventional method of measuring the density of the molten alloy is mainly a sessile drop method, the ray method, these two methods required to operate the software and hardware environment and the measurement means demanding, difficult to achieve a portable measurement and due to the introduction of radiation device makes it in personal security hazard.This article involves a float-type fiber Bragg grating molten alloy density sensor. Select Pb-Sn molten alloy as experimental subjects, fiber Bragg grating as the sensing element, equal strength cantilever as the sensing element. Using the submerged float measurement, Float through the buoyancy force transmission lever, arm leverage drive equal strength cantilever deflection of the mechanical operation, and it is repeatable. Then the center wavelength of Fiber Bragg Grating which paste rigidly in equal strength cantilever will shift. Upper and lower surfaces of strength cantilever are pasted grating to form a differential measurement, thus eliminating the interference of the temperature on the strain measurement to improve the accuracy of the density measurement. The main contents are as follows:1. According to the physical characteristics of the molten alloy we design a special ceramic material cone float immersed in the molten alloy, Equal strength cantilever strain by buoyancy transmission lever, equal armed lever, and other lever, Establish sensing model showed a linear relationship between the use of paste in the strength fiber Bragg grating wavelength shift change and buoyancy of float suffered molten alloy.2. According to the characteristics of the molten alloy sensor and its application environment, we design and produce the float-type fiber Bragg grating molten alloy density sensor, using ceramic material and processed into a reverse tapered to reduce the float adhesion of the molten alloy, The equal strength cantilever material:45#steel, Working length:65mm, the most bottom edge width:34mm, thickness:1.5mm. When to take two of the same material Fiber Bragg Grating original wavelength of1550nm, the theoretical sensitivity of the sensor can be calculated as1.07pm/(kg/m3); theoretical resolution:0.94(kg/m3)/pm;3. Molten alloy of Pb-Sn is selected for the measurement object, has to float in air, and the molten alloy, the recording grating wavelength value is repeated four experiments, The results show that four times measurement average value:7.86×103(kg/m3); root mean square error for216.362kg/m3.