First, aluminum die-cast molds are affected in a complex manner by factors such as being thermally affected by repeated heating and cooling during casting, pressure during casting, mold shape/material, quenching and tempering conditions, the surface treatment method, and machining. These factors can cause damage such as heat cracks, melting damage, and seizure. Among these damage factors, quenching, tempering, and the surface treatment method are particularly important.
Such aluminum die-cast molds are mainly made of alloy tool steel for hot dies, and since strength that can withstand many large parts and harsh impacts is required, SKD-61 and improved steel grades of SKD-61 with carbon content of 0.6% or less are widely used.
Heat treatment of such mold steel is a very important technology for effectively bringing out the characteristics and mechanical performance of a material, and the performance of the mold differs greatly depending on the quality of the heat treatment. In other words, even molds made of high-grade materials may cause problems during casting unless they are properly heat-treated.
Therefore, by combining Edison Hard treatment (EH-H process) for die casting dies and the quenching developed by our group company Licht Seiko Co., Ltd. that uses a proprietary furnace (engine-driven vacuum pressurized gas cooling furnace/high efficiency vacuum pressurized gas-oil cooling furnace) to perform the treatment, we can contribute to lengthening mold life while taking advantage of the characteristics of surface treatment.

EH-H treatment is an aluminum die-cast mold specification that aims to achieve erosion resistance and anti-heat cracking in aluminum.
Edison Hard Hyper (EH-H) is a process of covering the surface of the nitrided layer normally formed by EH treatment with an oxide film of 1 to 3 μm (improved magnetite (Fe3O4) oxide film).