Dynamic measurement of temperature field and deformation in hydraulic turbine blade at cooling stage of heat treatment
The hydraulic turbine blade is a kind of large, complex and curved casting. It is susceptible to significant warping deformation in the heat treatment process because of no-uniform cooling and phase transformation, which is a serious problem for the dimension control of the blade. A non-contact temperature field and dynamic displacement measurement system is established with the infrared thermal imaging system used for temperature measurement and special devices for the deformation measurement. It is adopted to investigate the temperature distribution and deformation behavior of a blade at the cooling stages of normalizing and tempering in production. The results reveal the temperature evolutions and dynamic deformation of the blade in heat treatment. The deformations of the blade mainly occur at the cooling stage of normalizing owing to the effect of uneven cooling and phase transformation. While, it is small during tempering in which only uneven cooling effect exists. This research and the results are of great significance to the exploration and study of the deformation behavior of hydraulic turbine blades. And the established system is useful for temperature fields and deformation measurement for parts during heat treatment.