Research On Casting Process And Properties Of Ductile Iron Castings Produced By Copper-based Alloy Mold

The objective of this paper is to develop a permanent mold casting technique with rapid solidification of metal melts by using high-conductive copper-based alloy molds and to obtain ductile iron castings with resultant refined grains. Taking as a typical example the ductile iron idle gear castings for automobile in our country, the casting process of ductile iron using water-cooled copper-based alloy molds was developed.The use of water-cooled copper-based alloy mold is an important step in the process, in which the heat of the metal mold can be carried away by cold water, and thus temperature of the permanent mold during the high speed casting process remains constant. According to the requirements for the permanent mold to insure high-conductivity, comparatively good wear resistance and easy machinability, a new Cr-Zr-Cu copper-based alloy was developed for permanent mold casting. Its chemical composition, mechanical properties and metallurgical processing technology were developed.Based on the Windows XP operating system, UG pattern software and FoxPro database, and using the UG secondary development function for the development of application program, the general framework of the CAD system for the permanent copper-based alloy mold was established. Methods for realizing the structural design module of the mold cavity were studied, aiming at achieving CAD/CAE software available for copper-based alloy mold.For the metal mold castings (e. g., the iron mold ductile iron idle gear and the copper mold ductile iron idle gear), a numerical simulation method for mold filling and temperature field calculation was proposed, so as to predict casting defects in the idle gear castings. Temperature variation during mold filling and metal solidification was measured, and the corresponding CAE software (Z-cast software) was written. The application of this technology is beneficial to the improvement of accuracy and efficiency of the permanent mold design and shortening of the manufacturing cycle.