Die soldering and corrosion failure of high temperature tool steel for high-pressure die casting Al alloy

Abstract

High-pressure die casting (HPDC) is regularly used to produce aluminum components. The die-casting molds are subjected to severe localized corrosion due to contact with the hot melted aluminum (700 °C) and accelerated by the intense thermal cycling generated by the cooling system. The correct understanding of each failure mode that occurs during the operation of these molds can increase tool life and reduce operational costs. Different components used in aluminum components production were evaluated after completing their useful tool life, and the failure modes were compared with two high-temperature laboratory tests, molten aluminum corrosion and die soldering tests. The primary crack mechanism observed in the HPDC die was heat checking, with a surface reaction of the tool steel with the molten aluminum. PVD coating increases the die's tool life, reducing the reactivity with the molten aluminum, which was observed in both laboratory tests. Die soldering tests represent the die mold behavior in HPDC production, showing a similar intermetallic phase and crack formation. Laboratory corrosion tests showed a more aggressive corrosion behavior than that observed in molds and dies used in HPDC industrial production.