Progress in the application of cold gas dynamic spraying to repairing continuous casting molds

A new continuous casting mold repairing method -- cold gas dynamic spraying (CGDS) is introduced. The study investigates the advantages of the CGDS process regarding repairing operation, such as convenient, in-situ repairation, little heat delivery, microstructural and dimensional stability and other special applications. Experimental results have demonstrated the relative density of the copper alloy coating is as high as 98.7%, and that no obvious difference can be observed between the CrZrCu substrate and the Cu alloy coating in terms of microstructures; thus the interface is quite difficult to be identified. The bonding strength and micro-hardness of the Cu alloy coating reach up to 37 MPa and 310 HV sub( 0.2), respectively. Complete recrystallization occurred after annealing at 900 degrees Celsius for one hour, while its micro-hardness remains as high as 124.1 HV02. All these results have indicated, that CGDS is a promising technology for repairing the continuous casting mold and that its future development is prosperous as well.