Study On The Cooling Capacity Of Partial Mould By Phase Transformation Heat Changing

It's easy to lead to hot spot at local of mould because of the casting complex shape or the factor of wall thickness. Series of problems result in the casting hot spot, such as the unbalance of casting temperature field, disordered solidifying and causing casting defect easily. At the same time, the hot spot disorder the mould temperature field. Unbalanced mould temperature field cause thermal fatigue of mould. This is an important factor which cause loss of life and degrade casting dimensional precision. Because the casting heat-transfer process is transient and nonlinear, the research of mould temperature field was based on experiment. As the development of computer technology and numerical simulation, it became possible that study mould temperature field by numerical simulation software. A new method of studying the relation between temperature field and its effected factors by CAE is presented in this thesis. The boss hot spot where casting defect happen easily is commonly among casting hot spot. This thesis studies the boss hot spot by ANSYS thermal solution. The cooling way is the key factor of effect the boss core hot spot. At the condition of natural cooling of core, this thesis research how core diameter, casting wall thickness and the wall thickness at the part of hot spot effect the hot spot of core; at the condition of water cooling of core, this thesis study how heat-transfer coefficient of cooling water effect the hot spot of core; at the condition of heat pipe cooling, this thesis study how the diameter of heat-pipe, the length ratio of condensation part and the heat pipe fin effect the hot spot core. Based on the above consideration, these conclusions were drawn from the simulation analysis: At the condition of natural cooling of core, analysis derived the relation expression between the D-value which is the result of the maximum temperature subtracting the temperature at casting center and the effective factors; at the condition of water cooling of core, analysis derived the relation expression between the D-value and convective heat-transfer coefficient; at the condition of heat pipe cooling, analysis derived the relation curve between the D-value and the way of cooling heat-pipe.