In plate forming by line heating the usage of water as a cooling source is common. However, the relationship between water-cooling and plate deformation is not well established. This reduces the possibility of automating the process. In order to solve this problem, the influence of the rate of cooling on inherent deformation is first examined. Then, the inherent deformation produced by line heating is studied in detail. Finally, the relationship between inherent deformation and heating condition is recorded into an inherent deformation database. This database can be used to directly predict inherent deformation due to line heating and therefore enable the automation of the process.
In plate forming by line heating, water-cooling is usually used due to its effectiveness in increasing plate deformation. However, the mechanism of forced cooling such as water cooling is highly complex and it is not fully understood. Therefore, it is necessary to create a method to predict the influence of water-cooling on plate deformation and therefore, enable the usage of automatic machines. Although there have been many papers reporting the line heating method, very few papers are dealing with the effect of water cooling on deformation of plates due to line heating, [e.g. Satoh, Matsui, Terai and Iwamura (1970), Jamg, Kim, Ha and Lee (2005), Ji, Yujun, Zhuoshang, Yanping and Jun (2006), Ha and Jang (2007)]. Not a clear relationship between water-cooling and deformation of plates due to line heating has been found yet. Various attempts have been made to understand the mechanism of heat transfer in pool boiling (the key to explain the influence of water-cooling on line heating process), [e.g. Davidson and Schueler (1960), Han and Griffith (1965), Mikic and Rohsenow (1969), Judd and Hwang (1976), Haramura and Katto (1983), Liu and Wang (2001), Wu, Yang and Yuan (2002), etc.]. However, the calculation of the convection coefficient is a difficult problem and cannot be described by using a single relationship.