Heat transfer during squeeze casting of aluminium alloy A380

Abstract

ABSTRACT In this study, a step die was made by P20 steel for squeeze casting aluminium alloy A380 with five different section thicknesses of 2, 4, 8, 12, and 20 mm under an applied pressure of 90 MPa. K-type thermocouples were employed to measure temperatures of the squeeze casting surfaces as well as three different depths, i.e., 2, 4, and 8 mm from the die inner wall at each step. With the temperature measurements, interfacial heat transfer coefficients (IHTC) at the casting and die inner surface and heat fluxes were determined by solving one-dimensional heat conduction formulae using the inverse method. The results of the calculated IHTCs showed that, upon the commencement of squeeze casting, the IHTC values for all the five steps rose rapidly. Before decreasing, the IHTC at each step reached its own individual pinnacles. As the section step thickness changed from 2 mm (step 1) to 20 mm (step 5), the IHTC peak values increased significantly. It took longer time for a thicker step to attain its peak IHTC value, and also to decrease its IHTC values to a low and steady level.