Influence of steel preheat temperature and molten casting alloy AlSi9Cu3(Fe) impact speed on wear of X38CrMoV5-1 steel in high pressure die casting conditions

摘要

This paper is a part of experimental research in the area of high pressure die casting (HPDC) mould wear. Influence of mould preheat temperature and molten aluminium alloy impact speed on total mould wear was researched using novel laboratory die casting testing equipment. Testing parameters were set to simulate HPDC of aluminium alloy AlSi9Cu3(Fe). The specimens were made from X38CrMoV5-1 hot work steel (H11). Experiment was designed using central composite design. Following the experiment design, 13 specimens were heat treated and the surface was modified by "Tenifer" nitrocarburizing. Specimen wear was measured by a Mettler B5 scale (Kusnacht, Switzerland) and shown graphically by 3D scan before and after the experiment; the 3D scans were overlapped to determine main wear areas. Response surface was acquired. Most influential tribological wear mechanisms were determined by ANSYS CFX 17.2 analysis. It was found that preheat temperature and molten aluminium alloy impact speed directly affects total wear of the mould surface. An increase of preheat temperature decreases total wear, while an increase of molten aluminium alloy impact speed increases total wear. Conditions for minimum and maximum wear were quantified; most significant wear was observed on sharp edges of nitrided mould material specimens. ANSYS CFX 17.2 hard particle erosion rate simulation suggested erosion occurrence mostly at impact angles perpendicular to the specimen surface. Other ANSYS CFX 17.2 simulation suggested occurrence of cavitation erosion.