Search Results for heat treatment simulation

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.

Heat treatment simulation helps to predict heat treatment results such as component microstructures, properties, residual stresses, and distortion, and thereby assists in reducing experimental effort in defining heat treatment parameters. This article discusses the modeling and simulation of age hardening as being the most important heat treatment to strengthen aluminum alloys. It provides information on the heat treatment simulation model, the yield strength model based on the responsible strengthening mechanisms, and the flow curve model based on mechanical tests. The article also discusses simulation of the quenching process, and provides examples for aluminum quenching simulation.

This article describes the integration of thermodynamic modeling, mobility database, and phase-transformation crystallography into phase-field modeling and its combination with transformation texture modeling to predict phase equilibrium, phase transformation, microstructure evolution, and transformation texture development during heat treatment of multicomponent alpha/beta and beta titanium alloys. It includes quantitative description of Burgers orientation relationship and path, discussion of lattice correspondence between the alpha and beta phases, and determination of the total number of Burgers correspondence variants and orientation variants. The article also includes calculation of the transformation strain with contributions from defect structures developed at alpha/beta interfaces as a precipitates grow in size. In the CALculation of PHAse Diagram (CALPHAD) framework, the Gibbs free energies and atomic mobilities are established as functions of temperature, pressure, and composition and serve directly as key inputs of any microstructure modeling. The article presents examples of the integrated computation tool set in simulating microstructural evolution.

Distortion, encompassing all irreversible dimensional changes, is of two main types: size distortion and shape distortion. This article provides an overview of the nature and causes of distortion and discusses the process and material aspects of distortion specific to steels and tool steels. It also discusses the prediction of distortion and residual stresses by heat treatment simulation for optimizing production processes. The advantages and limitations of heat treatment simulation are also described.

Dimensional and shape changes caused by heat treatment have been the subject of scientific and industrial research for a very long time. This article provides an overview of the complexity of distortion and stress generation during heat treatment of steels. It discusses the measurement and evaluation of dimensional and shape changes with examples. The article describes the mechanisms at work during the generation of stresses and distortion during heat treatment. A hypothetical experiment with increasing application to real life is used to develop a systematization of unavoidable size and shape changes. The article also provides information on the carriers of distortion potential that cause measureable size and shape changes.

Integrated computational materials engineering refers to the use of computer simulations that integrate mathematical models of complex metallurgical processes with computer models used in component and process design. This article outlines an example of a computer-aided engineering tool, such as virtual aluminum castings (VAC), developed and implemented for quickly developing durable cast aluminum power train components. It describes the procedures for the model development of the VAC system. These procedures include linking the manufacturing process to microstructure, linking microstructures to mechanical properties, linking material properties to performance prediction, and model validation and integration into the engineering process. The article discusses the benefits of the VAC system in process selection, process optimization, and improving the component design criteria.

Quench cracking is a brittle fracture phenomenon, and its occurrence depends not only on the stress changes but also on the mechanical characteristics of metals. Simulation of quenching processes has become possible in the analysis of quench cracking. This article commences with a discussion on the studies conducted to determine the origin of quench cracks, and then describes various test procedures for determining the susceptibility of quench cracking. It provides a description of the brittle fracture in terms of fracture mechanics and fracture toughness of quenched metals, and discusses the effects of impurities, hydrogen, and surface roughness on cracking. The article exemplifies simulation works applied to several successful cracking tests on cylindrical and complex-shaped steel parts.

This article illustrates the simulation procedure of casting process. It describes important elements and points of the simulations. These include the setting of clear simulation objectives, selection of proper simulation code, hints in modeling of shape and phenomena, initial and boundary conditions, physical properties, enmeshing, and evaluation of simulation results. The article also provides some insights into the application of models to real world problem for foundry process engineers.

This article presents the three levels of investigations of distortion engineering. On Level 1, the parameters and variables influencing distortion in every manufacturing step must be identified. More than 200 parameters can affect distortion. The design of experiments approach allows for the investigation of larger numbers of parameters by a limited number of samples, and can be structured into system analysis, test strategy, test procedure, and test evaluation. Level 2 focuses on understanding the distortion mechanisms by using the concept of distortion potential and its carriers. Distortion engineering aims to compensate distortion using the so-called compensation potential (Level 3). Level 3 discusses the measures to improve homogeneity, and respectively the symmetry, of the carriers of the distortion potential. The article also discusses the compensation of the resulting size and shape changes of the existing asymmetries by well-directed insertions of additional inhomogeneity/asymmetries in one or more of the distributions of the carriers.

This article discusses special considerations relative to induction heating of stainless steels and nickel-base superalloys. It focuses on the various industrial and high-temperature applications of induction heating to stainless steel and superalloy components, namely, primary melting processes, preheating for primary and secondary forming processes, heat treatments, brazing, and thermal processing for fusion welds. The article also provides information on computational modeling of induction heating processes for super alloys and stainless steels.

This article presents an overview of the techniques used in the design for heat treatment and discusses the primary criteria for design: minimization of distortion and undesirable residual stresses. It provides theoretical and empirical guidelines to understand the sources of common heat treat defects. A simple example is presented to demonstrate how thermal and phase-transformation-induced strains cause dimensional changes and residual stresses. The article concludes with a discussion on the heat treatment process modeling technology.

This article provides information on the boundary conditions that must be applied to model the heat-transfer coefficient (HTC) in a component being cooled. It describes the historical perspective of various experiments to determine the HTCs. Computational fluid dynamics codes have also been used to predict the HTCs around a part. The article provides information on the various modeling studies used to predict cooling rates in a component. The prediction of residual stresses by validation and optimization of residual stress models is also discussed. Several techniques, such as models neglecting and incorporating material transformation effects, used to predict residual stresses are reviewed. The article also explains the various aspects of models used to prevent cracking during heating and quenching.

This article provides a detailed discussion on the effect of boron in heat-treated steel and thermomechanically-simulated steel. It describes the boron hardenability mechanism and the effect of composition and heat treatment parameters on boron hardenability. The article examines the hardening behavior of unalloyed boron steel and low-alloyed boron steel in heat treatment experiments by varying the austenitizing temperatures and cooling conditions. It also discusses the applications of boron steels.

Low-pressure carburizing (LPC) is one of the most popular case-hardening processes and is applied to increase the fatigue limit of dynamically loaded components. It takes place in a pressure range between 5 and 15 mbar (4 and 11 torr) and at temperature range between 870 and 1050 deg C. The LPC process runs in two different types of equipment: single-chamber furnaces and treatment chambers. This article reviews the use of simulation software for prediction of carbon profiles and typical quality control procedures. It describes the physical principles and typical applications of LPC.