Research And Development On Key Technology Of Temperature Control For Big-size And Complex Die Casting Molds

Temperature control has significant impact on filling and solidification of molten metal, die span-life and casting defects. It must be one of the parameters controlled by users. There are pre-heating and cooling two parts in temperature control. In order to solve these problems ,such as low speed, heavy energy cost, and pollution of the environment in pre-heating stage, temperture of the fine core needles hardly effective controlled, high temperature of core needles, short life in cooling stage, in this paper , the die temperature control equipment based on overheated water with high presuure and the die core needle temperature control equipment based on cycle cooling-water with high pressure have been developed, which will meet the present production need in large valume dies and have significant impacts.In this paper, a kind of temperature controller based on high pressure and overheated water (Water Temperature Controller for short) has been designed and producted, with the pressure of 0.6MPa, maximum heated temperature of 160℃and flow rate of 50L/min. It owns some functions such as pre-heating, automatic cooling, water charging automatically, keeping constant pressure and temperature control. The experimental results showed that die temperature had been preheated over 100℃by in the short time, higher approximately 60℃than that of oil temperature controller. Meanwhile, pre-heated time of die had been reduced 50%, compared to oil temperature controller under the same temperature. Consequently, the equipment has some advantages with higher heating efficiency, faster heating-velocity , energy saving and no pollution etc. The apparatus was successfully applied to a complicated communication frame casting instead of oil temperature controller.Core needle cooling controller which have been designed and manufacuted in this paper includes several functions such as water temperature controlling automatically, regrigeration, circulation water cooling and air blow cooling. The equipment sets up manual operation and automatically operation, meanwhile set up independent control system for respective mode. Consumer can choose modes conveniently by using change-over switch. Refrigerating capacity is 18KW, flow rate is 50L/min and the maximum work presure is 1 Mpa. The experimental results demonstrated that in the process of developing a complicated sub-frame casting in one domestic pcv, the temperature of core needle can be high to 200～260℃without using the cooling controller; it will be reduced to 100～150℃in the condition of using controller in automatically mode; it will further reduced to 65～120℃in the condition of using controller in manual mode.Meanwhile,compared with X ray pictures in three modes , we can conclude that porositys and cracks in core needle parts were ideal.