In this research, the design of an eddy current sensor system that continuously monitors age hardening during aging of heat treatable alloys was modified to allow for operation at temperatures up to 595 deg C. With two eddy current coils in an impedance bridge circuit, eddy currents are generated in a pure aluminum reference sample standard and an age harden able test sample. The difference in the resistivity of the aging test sample relative to the reference sample results in a bridge unbalance voltage, Delta V sub BCA, which is continuously measured by a multimeter. Also, calibration procedures were developed to allow conversion of the values of delta V sub BCA to a resistivity difference, Delta p=Ptest - Pref, between the test and reference samples. These calibration curves were generated by measuring delta V sub BCA at various temperatures for six test sample standards of known resistivity. The resistivity of the aging sample is determined by adding the known resistivity value for pure aluminum to Delta p. Real-time monitoring of an aging alloy's resistivity may allow heat treaters to integrate this monitoring system with a control system to achieve 'intelligent heat treating'.
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机译：在这项研究中，对涡流传感器系统的设计进行了修改，该系统可连续监控可热处理合金的时效过程中的时效硬化，以允许在高达595℃的温度下运行。在阻抗桥电路中使用两个涡流线圈时，涡流在纯铝参考样品标准品和可老化的测试样品中生成。老化测试样品相对于参考样品的电阻率差异导致电桥不平衡电压Delta V sub BCA，该电压由万用表连续测量。同样，开发了校准程序以允许将V V sub BCA的值转换为测试样品与参考样品之间的电阻率差Delta p = Ptest-Pref。这些校准曲线是通过在六种已知电阻率的测试样品标准品的不同温度下测量delta V sub BCA来生成的。老化样品的电阻率通过将纯铝的已知电阻率值添加到Δp中来确定。实时监控时效合金的电阻率可以使热处理人员将该监控系统与控制系统集成在一起，以实现“智能热处理”。
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