Research on Model of Plastic Flow Heat Transfer during Linear Friction Welding for Low Melting Point Metal

Abstract

With the self-developed physical simulation equipment of linear friction welding, the plastic flow heat transfer simulation experiment of low melting point Lead metal was implemented. A physical model of plastic flow heat transfer of linear friction welding low melting point metal was established based on the process of the Lead metal plastic flow recorded by high speed digital camera and the Lead metal temperature variation recorded by infrared thermal imager. Introducing the plastic flow element into one-dimensional unsteady heat transfer differential equation, heat transfer mathematical model of plastic zone, perpendicular to the direction of vibration, was proposed. Using finite difference method to solve this mathematical model, calculated value of this model and measured temperature was compared. The results show that the two values correspond basically, which indicates that the proposed model could be used to characterize the process of heat transfer of plastic zone during linear friction welding low melting point metal.

Numerical Simulation of Temperature Field and Stress Field to Multiple Laser Cladding Co Coatings

“…Fig. 4 Temperature distribution of multi pass laser coatings with different scanning speed (a), (b) 3 mm/s (c), (d) 5 mm/s Because of molten pool is very small, and the cooling rate of the molten pool is very fast, instantaneous cooling rate o is calculated by heat transfer theory (rough estimate is used, solidification and crystallization conditions of pool are only considered) [5] , instantaneous cooling rate of molten pool for thick plate as…”

“…Instantaneous cooling rate of molten pool can be obtained by a correction coefficient multiply formula (5) for the work-piece (8 ~ 25 mm) as…”

“…Whether the actual situation is accurately reflected by analysis results is largely depended on the heat source model which is appropriate choose or not, the calculating precision of temperature field has important effect, especially on the molten pool area near the heat source [5] . Considering the influence of heat source, a part of heat of laser cladding process is input to the work-piece by heat conduction and radiation, the heat source model of Gauss distribution is choose in this paper, and Gauss distribution function is used as follow.…”