Modeling and Simulation of Steel Heat Treatment—Prediction of Microstructure, Distortion, Residual Stresses, and Cracking

Abstract

This article describes the fundamental concepts of heat treatment simulation, including the physical events and their interactions, the heat treatment simulation software, and the commonly used simulation strategies. It summarizes material data needed for heat treatment simulations and discusses reliable data sources as well as experimental and computational methods for material data acquisition. The article provides information on the process data needed for accurate heat treatment simulation and the methods for their determination. Methods for validating heat treatment simulations are also discussed with an emphasis on the underlying philosophy for the selection and design of validation tests. The article also discusses the applications, capabilities, and limitations of heat treatment simulations via selected industrial case studies for a better understanding of the effect of microstructure, distortion, residual stress, and cracking in gears, shafts, and bearing rings.

A Review of the Boiling Curve with Reference to Steel Quenching

“…The term that appears inside the curly brackets represents the local heat transfer coefficient for a single-phase fluid flowing parallel to the wall. Equation (2) shows that heat flux increases with the square root of the fluid velocity. During quenching, the previous equation is only valid under the single-phase convection regime.…”

“…1 Units may be rpm or m/s as it is indicated. 2 Computed values from CHF, T max and T f data. 3 28 and 44 mm are the diameters of cylindrical probes, steel grade AISI 1040.…”

“…Each cooling curve is used in the solution of the Inverse Heat Conduction Problem to determine the heat flux at the wall as a function of time. The heat transfer coefficient can be computed from this heat flux using Equation (2). In essence, this procedure measures the temperature evolution at one, or more points, within the workpiece and then uses the solution of the IHCP to compute the temperature evolution in the rest of the workpiece.…”

“…For example, in ref. [2], heat transfer coefficient is also a function of position on the workpiece surface and time. The authors do not explain additional factors, other than fluid flow, affecting this dependence.…”

“…Two classical handbooks on heat treatment and quenching [1,2] were identified as the point to start for this work. In addition, the document reflects opinions emerged from more than 20 years of professional experience (FAAG), in production line, laboratory and computer modeling, on heat transfer in continuous casting of steel.…”