Quantitative Correlation between Interfacial Heat Transfer Coefficient and Pressure for 19Cr-14Mn-0.9N High Nitrogen Steel Cylindrical Ingot

This research is aimed to correlate heat transfer coefficient to pressure at the interface between 19Cr-14Mn-0.9N high nitrogen steel cylindrical ingot and cast iron mould, during the pressurized solidification process of cylindrical ingot. The correlations were obtained by mathematical inverse model of heat conduction problem. Validation results indicate that this model is applicable to investigate the change in interfacial heat transfer coefficient during the pressurized solidification process of 19Cr-14Mn-0.9N high nitrogen steel, and guarantee the correlation accuracy. Combing with theoretical derivation for cylindrical steel ingot, the change in interfacial heat transfer coefficient with time can be described by hf,0.5 = 679.68t−0.12 W/(m3·K) for 0.5 MPa, hf,0.85 = 753.53t−0.12 W/(m3·K) for 0.85 MPa and hf,1.2 = 790.39t−0.12 W/(m3·K) for 1.2 MPa, quantitatively. Meanwhile, an empirical formula was presented to correlate interfacial heat transfer coefficient to pressure, which can be taken as heat transfer boundary to simulate the change in solidification state of 19Cr-14Mn-0.9N high nitrogen steel cylindrical ingot with pressure.