Erosion mechanism of austenitic steel and martensitic steel in aluminum alloy melt

Due to the washout of aluminum alloy melt, the erosion failure of steel is a complex problem in die casting. To explain the erosion mechanism in flowing aluminum alloy melt, 6Mn14Cr3Mo2Si1V2 steel, and 4Cr5Mo2V steel were stirred at 700 degrees C in ADC12 melt. The erosion characteristics were studied via the scanning electron microscope. At the test time increased from 600 to 1800 s, the weight loss rate of 6Mn14Cr3Mo2Si1V2 steel increased from 5.0% to 14.1%, and the weight loss rate of 4Cr5Mo2V steel increased from 5.4% to 12.8%. If the corrosion time reaches more than 1200 s, 6Mn14Cr3Mo2Si1V2 steel has lower erosion resistance because intergranular corrosion causes the matrix to peel off. Besides, the lump-like Vanadium carbides with a low erosion rate act as obstacles to prevent the invasion of aluminum alloy melt. The reaction product of steel and aluminum alloy melt is identified as Fe2Al8Si. Fe2Al8Si is easier to form in 4Cr5Mo2V steel than in 6Mn14Cr3Mo2Si1V2 steel. The growth activation energy of Fe2Al8Si in 6Mn14Cr3Mo2Si1V2 steel and 4Cr5Mo2V steel is 89.2 and 71.3 kJ/mol, respectively.