Abstract : Since welding thermal cycle has an important influence on the microstructure and properties of the heat-affected zone, the welding thermal cycle acquisition and analysis system uses LabWindows/CVI software as the development platform and a hardware system based on a data acquisition card as the core to collect welding thermal cycle data in real time and analyze it with welding CCT diagrams. This makes it easier to predict the microstructure and properties of the heat-affected zone. Keywords : welding thermal cycle; LabWindows/CVI; data acquisition; welding CCT diagram 1. Introduction With the development of modern welding technology, the requirements for welding quality are getting higher and higher. Since welding thermal cycle has an important influence on the microstructure and properties of the heat-affected zone[1], it has a certain impact on the welding quality of the welded joint and has therefore received attention from welding technicians. If welding thermal cycle process data can be collected accurately and in a timely manner and analyzed with welding CCT diagrams, the microstructure and properties of the heat-affected zone can be predicted more easily, thus providing a basis for selecting welding heat input energy, preheating temperature and formulating welding process. However, it is difficult to meet the needs of welding process analysis by using traditional pointer instruments and oscilloscopes, but computer-based virtual instrument technology can meet such requirements. Virtual instruments are computer-based hardware and software testing platforms. They can use software to construct virtual instrument panels on a microcomputer screen, and with sufficient hardware support, they can sample signals and obtain measurement results through software processing under offline conditions [2]. This paper uses LabWindows/CVI software as the development platform to collect welding thermal cycle data in real time and analyze it in conjunction with welding CCT diagrams. 2. Hardware Design The hardware part of this system consists of a microcomputer, thermocouple temperature sensor, amplification and filtering circuit, data acquisition card, etc. The system hardware device is shown in Figure 1. During the welding process, the thermocouple collects the temperature signal of the welding heat-affected zone, converts the temperature signal into a voltage signal, and supplies it to the acquisition system [3]. Before the signal enters the data acquisition card, it passes through the amplification and filtering circuit of the hardware part to filter out the interference signal in the voltage signal and amplify the voltage signal to be collected by an appropriate multiple. After passing through the data acquisition card, the analog signal is converted into a digital signal, that is, A/D conversion is performed so that the input voltage signal can be recognized by the microcomputer system. 2.1 Thermocouple Temperature Sensor Welding Thermal Cycle Acquisition and Analysis System Based on Virtual Instrument Technology Full Text Download