Finite Element Simulation Of The Transient Temperature Field During Laser Surface Quenching And Forecasted Depth Of The Hardness Layer

Laser surface quenching is a technical multi-parameter synthetic process, which is a very difficult process to use for measuring transient temperature distribution directly by experimentation. According to this situation, it is also very difficult to quantify those factors which affect the layer thickness of the metallographic changes. With the development of advanced computer technology, it is now much easier to quantify these factors. This paper simulates the temperature field associated with laser surface quenching using ANSYS - a finite element analysis software, and a series of studies are carried out based on this simulation.This paper sets up a three-dimensional finite element analysis model using ANSYS according to the heat transfer differential equation of Physical antetype. Furthermore, considering that the load condition is close to the actual, the paper simulates the transient changed process of the temperature field during the laser scanning. During the laser quenching process, the hardness layer distribution remains nearly the same, aside from the input-output area. If only the hardness layer distribution is considered, the paper also sets up a two-dimensional model of the laser surface quenching, which decreases the operation largely and improves the precision at the same time.The hardness layer depth during the laser surface quenching is the main guide line to evaluate whether or not the effects are good. It is associated with technical parameters like the laser power P, the facular dimension, and the scanning speed V. It is also associated with the energy absorption of the material. This energy transfer coefficient 77 is defined as the ratio between the material absorption energy and the laser energy. The factors that affect 77 include the optical energy loss when the beam of light goes through the optical system, the loss caused by the convection and the radiance, and the absorption coefficient change following the temperature in the pretreated material surface. Combining the experimental datumand the simulated datum, and further studying the changed rule between the energy transfer coefficient η and the technical parameter P and V, the paper sets up a mathematic model to forecast the layer depth, which is verified with high precision through experimentation. Compared with the iterant experimentation, the 5% tolerance of the forecasted layer depth is controlled and also verified by the simulation. This paper analyses the energy transfer coefficient during the laser surface quenching using ANSYS; however, it is just for 45" steel with the same surface. Therefore, it does not be used for all materials or the different pretreated case. This paper mainly provides a new study, and based on the advanced computer technology, it provides some insight for studying how to precisely control the technical parameters and the layer depth of the metallographic changes. Until now, it has always been an assumption when forecasting the hardness layer thickness for the metallographic changes. This paper tries to provide a new method for precisely forecasting the layer thickness from this point.This paper also analyzes the evenness for the hardness layer after the laser surface quenching, which mainly indicates the difference between the input-output area. The optimization for the cross section of the hardness layer can be reached by the change of the facular power and density distribution. It is also verified abstractly by the ANSYS simulation. This paper tries to study how to decrease the difference in the input-output area, and infers a set of rules by mass of experimentations.