Enhanced cooling channel efficiency of high-pressure die-casting molds with pure copper linings in cooling channels via explosive bonding

Abstract

The cooling efficiency of aluminum die-casting molds is critical to prevent soldering, extend mold life and manufacture high quality castings. In this paper, we discuss a method of inserting a pure copper (Cu) lining using explosive expansion bonding process. A pure Cu bush was inserted into a cooling channel of die casting mold and bonded to the inner surface of the cooling channel through explosive bonding technology to form a copper lining in the cooling channel to improve the cooling performance of high pressure die casting (HPDC) mold fabricated from SKD61 material. Furthermore, the microstructure and mechanical properties of the bonding zone between the SKD61 tool steel and pure Cu lining were analyzed. By changing the thickness of the Cu bush, stand-off distance between the Cu bush and the predrilled cooling hole, and mold heat treatment sequence, the optimal explosive bonding process parameters were established for these cases. A high-frequency induction heating-cooling system was used to examine, the performance of the cooling channel sample bonded with pure copper lining, and it was confirmed that the cooling rate was improved by 12 %. After inserting the pure copper lining into the cooling channel for a practical die casting application, it was confirmed that the mold temperature was lowered, and soldering was prevented. The explosive bonding technology used in this study is an effective method to bond pure copper lining onto the inner surface of a cooling channel, thereby providing an alternative approach to increasing the cooling efficiency.