Energy Analysis Of Keyhole Plasma Arc Welding

Keyhole plasma-arc welding was named by the unique "keyhole effect" which means that in the plasma arc welding process. Plasma produces great arc power and has a "dig" affect to the weld pool as well as formation of a hole. Since the law keyhole plasma arc welding technique comes out, it was concerned by academic and industry. In recent years , under the development of monitoring and control technology, this method of welding has more of the new development. Keyhole plasma arc welding is wildly used in welding of the stainless steel and so does the nickel base alloy. For the high density of Plasma arc energy, the work piece can be penetrated and gets a small hole along the axis. This method can realize one-sided weld the two-sided forming. Compared to TIG, it has a higher superiority. In keyhole plasma arc welding process, the key factor is the transform of the Plasma and the keyhole behavior of the weld pool is affecting the stability and quality of welding.Through designing the contrast experiment for many times, the main welding parameter under this experimental welding condition can be obtained, simultaneously, the keyhole master data can be obtained, such as the upper and lower surface pool width, weld pool back dragging angle, with which a plasma arc energy distribution and loss model was established, and a qualitative analysis was done. And then force and energy balance was calculated quantitatively, plasma arc energy equation and its derivation process was established and thereby plasma arc energy and loss was calculated.In this paper, keyhole model and formation mechanism of the keyhole was conducted a comprehensive discussion. Through establishing of geometry, physics, mathematical model of keyhole for further study laying the foundation, for providing a basis for numerical simulation. Through the keyhole of plasma arc welding analysis, establishment of a set of available analytical methods, improving welding process, optimizing the welding parameters were provided help. Heat welding process on the establishment of keyhole formed a decisive role. Therefore, plasma arc welding power conversion analysis and the numerical simulation of the welding process, can provides an important basis for the data for keyhole plasma arc welding have important theoretical and practical value.