Steel Composition
The Steel Composition node is used to specify the chemical composition of a steel in terms of weight percentages of its alloying elements. Different empirical relationships are then used to establish characteristic transformation temperatures to be used in phase transformation modeling. In addition, the equilibrium phase fractions of metallurgical phases are computed as functions of temperature.
Steel Composition
In the table Weight percent of alloying elements, specify the weight percentage (wt%) of each alloying element. For example, type 0.4 for Carbon for a steel with 0.4 percent carbon by weight (wt%).
Definitions
This section is used to specify the particular models used to compute composition-dependent phase transformation temperatures.
•
Under Ae1 and Ae3 temperatures, specify how to model the Ae1 and Ae3 lines of an iron–carbon (Fe–C) diagram. If Andrews is selected, (constant) Ae1 and (nonlinear) Ae3 temperature lines are computed using empirical relationships based on the specified alloying content of the steel. If Parameterized is selected, (constant) Ae1 and (linear) Ae3 temperature lines are given in terms of three characteristic values. Specify the carbon concentration at the eutectoid, . Select Upper Ae3 temperature to give the Ae3 temperature at zero carbon concentration, , or select Ae3 to specify Ae3 directly. Specify the Ae1 temperature.
•
Under Bainite start temperatures, specify how to model the bainite start temperature. Select Steven–Haynes Bs or Kirkaldy–Venugopalan Bs.
•
Under Martensite start temperatures, specify how to model the martensite start temperature. Select Andrews Ms or Steven–Haynes Ms.
Transformation Temperatures
Select Calculate equilibrium phase fractions to compute the equilibrium phase fraction of ferrite, as well as equilibrium phase fractions for pearlite and bainite. Select Define phase transformation functions to enable the definition of functions used by the Microstructure based phase transformation model.
Equilibrium Phase Fractions
This section is available if Calculate equilibrium phase fractions has been selected. Specify the maximum ferrite solubility (at the eutectoid temperature), . Under Ferrite formation below the eutectoid, specify how ferrite is formed below the temperature Ae1. Select None to set the ferrite equilibrium phase fraction to zero below the eutectoid (no formation of free ferrite). Select Constant to set the ferrite equilibrium phase fraction below the eutectoid equal to that at the eutectoid temperature. Select Hultgren extrapolation to model the ferrite equilibrium phase fraction based on the linear extrapolation method by Hultgren. For Hultgren extrapolation, specify the lowest temperature of the ferrite region in the Fe–C diagram, , and the lowest temperature for the formation of free ferrite, TC.
Equilibrium Phase Fractions
Phase Transformation Modeling
This section is available if Define phase transformation functions has been selected. It is used to define functions that become available to the Microstructure based phase transformation model in the Phase transformation node. Specify an expression for the ASTM grain size number GASTM. Select a Phase transformation model formulation— Kirkaldy–Venugopalan or Li–Niebuhr–Meekisho–Atteridge. For Kirkaldy–Venugopalan, the phase transformation functions can be modified to account for the presence of boron. Select Åkerström–Oldenburg modification for boron steel, and then under Weight percent of boron, enter an expression for wt%B.