Developing 1D MM of Axisymmetric Transient Quenched Chromium Steel to Determine LHP

Abstract

The modelling of an axisymmetric industrial quenched chromium steel bar AISI-SAE 8650H based on finite element method has been produced to investigate the impact of process history on metallurgical and material properties. Mathematical modelling of 1-dimensional line (radius) element axisymmetric model has been adopted to predict temperature history and consequently the hardness of the quenched steel bar at any point (node). The lowest hardness point (LHP) is determined. In this paper hardness in specimen points was calculated by the conversion of calculated characteristic cooling time for phase transformation t8/5 to hardness. The model can be employed as a guideline to design cooling approach to achieve desired microstructure and mechanical properties such as hardness. The developed mathematical model is converted to a computer program. This program can be used independently or incorporated into a temperature history calculator to continuously calculate and display temperature history of the industrial quenched steel bar and thereby calculate LHP. The developed program from the mathematical model has been verified and validated by comparing its hardness results with commercial finite element software results.

Developing 1-Dimensional Transient Heat Transfer Axi-Symmetric MM to Predict the Hardness, Determination LHP and to Study the Effect of Radius on E-LHP of Industrial Quenched Steel Bar

“…Quenching is physically one of the most complex processes in engineering, and very difficult to understand. Simulation of steel quenching is thus a complex problem [2,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Quenching is a heat treatment usually employed in industrial processes in order to control mechanical properties of steels such as toughness and hardness [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…Simulation of steel quenching is thus a complex problem [2,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Quenching is a heat treatment usually employed in industrial processes in order to control mechanical properties of steels such as toughness and hardness [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The process consists of raising the steel temperature above a certain critical value, holding it at that temperature for a specified time and then rapidly cooling it in a suitable medium to room temperature [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…Quenching is a heat treatment usually employed in industrial processes in order to control mechanical properties of steels such as toughness and hardness [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The process consists of raising the steel temperature above a certain critical value, holding it at that temperature for a specified time and then rapidly cooling it in a suitable medium to room temperature [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The resulting microstructures formed from quenching (ferrite, cementite, pearlite, upper bainite, lower bainite and martensite) depend on cooling rate and on chemical composition of the steel [3,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

“…The process consists of raising the steel temperature above a certain critical value, holding it at that temperature for a specified time and then rapidly cooling it in a suitable medium to room temperature [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The resulting microstructures formed from quenching (ferrite, cementite, pearlite, upper bainite, lower bainite and martensite) depend on cooling rate and on chemical composition of the steel [3,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Quenching of steels is a multi-physics process involving a complicated pattern of couplings among heat transfer, because of the complexity, coupled (thermal-mechanical-metallurgical) theory and non-linear nature of the problem, no analytical solution exists; however, numerical solution is possible by finite difference method, finite volume method, and the most popular one -finite element method (FEM) which will be used in this study [9][10][11][12][13][14][15][16][17][18][19]…”

“…The resulting microstructures formed from quenching (ferrite, cementite, pearlite, upper bainite, lower bainite and martensite) depend on cooling rate and on chemical composition of the steel [3,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Quenching of steels is a multi-physics process involving a complicated pattern of couplings among heat transfer, because of the complexity, coupled (thermal-mechanical-metallurgical) theory and non-linear nature of the problem, no analytical solution exists; however, numerical solution is possible by finite difference method, finite volume method, and the most popular one -finite element method (FEM) which will be used in this study [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. A larger diameter rod quenched in a particular medium will obviously cool more slowly than a smaller diameter rod given with a similar heat treatment [4].…”