The measurement of surface tension in casting processes plays a crucial role in ensuring the quality of sand used for mold making. Zou Qiming and Li Dayong from Harbin University of Science and Technology, located in Harbin, Heilongjiang Province (150080), have conducted extensive research on sand quality parameters and their influencing factors. They emphasize that relying solely on a limited number of performance indicators to control sand quality is not effective, as it can be both time-consuming and operationally complex.
The most critical factors affecting the quality of wet clay sands are the effective clay content and water content. By maintaining these within optimal ranges through a well-designed sand mixing process, high-quality molding sand can be produced. To address this, a new rapid method for determining effective clay and water content has been proposed. This method, known as the dual-power secondary excitation technique, involves applying an AC source first to measure AC resistance, followed by a DC source to measure DC resistance within a short time frame. The AC resistance helps eliminate the influence of moisture, allowing the DC resistance to reflect only the clay content. Based on this principle, numerous experiments were conducted, leading to the development of an online rapid detection system for sand quality. The device uses an 8098 microcontroller, along with analog signal amplifiers, multiplexers, and a sampling mechanism. It automatically collects samples, applies AC and DC sources, measures conductance values, temperature, and compaction, and then calculates moisture and clay content, displaying the results on a screen or printing them out.
A fast carbon meter for portable steel melt furnaces was also developed by Shi Xudong and Li Dayong from Harbin University of Science and Technology. Accurate and rapid carbon content measurement in molten steel before casting is essential for controlling the mechanical and casting properties of steel castings. Traditional methods lacked scientific accuracy, relied heavily on operator experience, and were slow, often resulting in high costs that many found impractical. To overcome these challenges, a new, portable stereometer was designed. This device features a novel sampling system that supports both thermal and cold sampling, depending on the situation. The thermal sampling system includes a heat-resistant quartz tube and a quick-connect handle, while the cold sampling system is similarly structured but optimized for lower-temperature conditions. The single-chip measurement system is based on a low-power microcontroller, incorporating low-power components for signal processing, data storage, and display. The result is a compact, lightweight, and battery-powered device that can measure carbon content in molten steel in just 5–20 seconds, offering a practical solution for foundries.
Wang Xiaoming and Li Dayong from Harbin University of Science and Technology have also developed a fast quality analyzer for single-chip cast iron furnaces. By integrating microelectronics and computer technologies with thermal analysis principles, they created a rapid testing device that enhances the control of casting quality. The system, built around an 8098 microcontroller, includes a 16-bit display, memory, a 24-key keyboard, and a microprinter. It also features four high-precision preamplifiers, an alarm circuit, and a multi-channel power supply, making it a reliable and efficient tool for real-time quality assessment in the foundry industry.
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