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无论是蠕墨铸铁或球墨铸铁生产,其关键技术都是正确控制石墨形态。近几年来,铸造工作者在蠕铁质量检测与控制方面已经取得了较大进步,探索出许多先进方法,如:热分析法、共晶膨胀率法、相对导热率法、感抗法等。这些方法与金相法相比,虽然具有快速检测、操作方便的优点,但测试速度仍然不能满足自动化生产的需要。从这一点看,有必要研究一种新的检测方法及装置,以实现铁水石墨形态的炉前快速检测。本论文中,将详细介绍一种用于炉前快速检测蠕铁石墨形态的新方法和新装置。该新方法称为“气泡幅频当量法”,其基本思想是:通过一探头装置向铁水中吹入气体,以所吹气泡个数、气泡压力变化幅值及其相关参数形成的当量表面张力表征铸铁石墨形态。基于新方法研制的新装置主要由:信号采集系统(三路传感器)、信号调理电路、单片机数据处理系统及外转设备、微型气源和电源等部分构成。模拟测试及生产现场测试结果表明,该新方法用于蠕铁石墨形态的炉前快速检测是可行的。新装置具有操作简便、测试速度快、准确度高等特点。整个测试过程仅5s,测试准确率高于95%,适合实际铸造生产应用。
Whether it is vermicular cast iron or ductile iron production, the key technologies are the correct control of graphite morphology. In recent years, foundry workers have made great progress in the detection and control of the quality of vermicular iron. Many advanced methods have been explored, such as thermal analysis, eutectic expansion, relative thermal conductivity and inductive reactance. Compared with the metallographic method, these methods have the advantages of rapid detection and convenient operation, but the test speed still can not meet the needs of automated production. From this point of view, it is necessary to study a new detection methods and devices to achieve the rapid detection of hot metal before the furnace. In this paper, a new method and a new device for rapid detection of vermicular graphite morphology in the furnace are described in detail. The new method is called “Bubble amplitude-frequency equivalent method”. The basic idea is: equivalent surface tension formed by blowing gas into molten iron through a probe device, the number of bubbles to be blown, the variation amplitude of bubble pressure and its related parameters Characterization of cast iron graphite morphology. The new device based on the new method is mainly composed of signal acquisition system (three-way sensor), signal conditioning circuit, single-chip data processing system and external device, micro air source and power supply. The simulation test and production field test results show that the new method is feasible for the rapid detection of vermicular graphite morphology in the furnace. The new device is easy to operate, test speed, high accuracy and so on. The entire test process is only 5s, the test accuracy is higher than 95%, suitable for actual casting production applications.