Interfacial Heat Transfer Coefficient Between Sand Molds and Cast Steel: Recent Advances in Identification, Modeling, and Control

Accurate characterization of the interfacial heat transfer coefficient (IHTC) at the steel-sand interface is central to predictive simulation of solidification, porosity, microstructure, residual stress, and surface integrity in sand casting. Over the period 2022-2025, progress in this area has accelerated along three main directions: (i) robust inverse heat conduction methods (IHCP) with improved regularization and optimal experimental design; (ii) physics-aware machine-learning surrogates that map process variables to transient IHTC; and (iii) targeted experiments that isolate the roles of coating chemistry and thickness, sand permeability, and contact pressure, including frozen-sand regimes. This paper synthesizes recent advances and proposes a unified workflow for reliable IHTC identification and control in sand-cast steels. The contributions are fourfold: 1.A standardized inverse workflow integrating optimal sensor placement, regularized estimation, and posterior uncertainty quantification; 2.Consolidated experimental evidence on the influence of coating type, coating thickness, and sand system on early-time IHTC peaks and late-time plateaus; 3.A hybrid physics-ML framework for generalizing IHTC across casting geometries and process windows; 4.Practical parameter windows and implementation guidelines for industrial steel casting. The methodology is demonstrated via representative case studies on coated and uncoated molds, different sand compaction levels, and frozen-sand interfaces. Identified IHTC histories are validated against measured temperatures and microstructural indicators. The results show that properly designed inverse setups can reduce the uncertainty in IHTC estimates by more than half relative to ad-hoc thermocouple layouts, and that coating and mold preparation can be tuned systematically to achieve target cooling rates in cast steels.