Nature of the white layer in molds for die casting of copper alloys

1. The white layer in the surface of molds for die casting copper alloys consists of a solid solution of copper in α phase. 2. With increasing depth of the white layer the tendency to crazing increases and the mold life decreases. 3. The conditions for formation of the white layer depend on the composition of the steel. The interaction with liquid copper alloys (thickness of the white layer) is smaller in steels with a high chromium content (10–12%). 4. For molds used in die casting copper alloys it is expedient to use corrosionresistant and heat-resistant steel of the 2Kh10VMNF type (or steel 18Kh12VMBFR, GOST 5632-72).