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Subroutine MAP_STEEL_CCT

1. Provenance of code.
2. Purpose of code.
3. Specification.
4. Description of model's operation.
5. References.
6. Parameter descriptions.
7. Error indicators.
8. Accuracy estimate.
9. Any additional information.
10. Example of code
11. Auxiliary subroutines required.
12. Keywords.
13. Download source code.
14. Links.

Provenance of Source Code

E-mail:dg241@cam.ac.uk
 
 

Added to MAP:  2002.

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Purpose

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Specification

Description

There is a script ('start_mdl') that starts all the submodels needed and even does the housekeeping deleting unwanted temporary files once the calculations are over, leaving only the 'results.dat' and 'evolphse.dat' files (in case of being interested in the complete set of calculation results, use instead 'start_mdl_nrm' and 'rm_files').

There are three modes of operation with this model. The first mode does not require a temperature history file, whereas the other two do. Instead, in the first one, a constant cooling rate is asked for and used throughout the calculations. The only difference between the second and the third mode is the method they use to determine the suitable cooling rates from the temperature history file. When using a smooth thermal history, like when it has been calculated using some simulation method, the second mode would be more adequate. The third mode should be used when the thermal history file is noisy, i.e. when it consists of experimental data.

The first part of model (prepare.f) starts reading the composition of the steel from a file called 'compos.dat', its equiaxed austenite grain size from 'grainsz.dat' and the cooling cycle from 'temper.dat'. The cooling cycle is assumed to start at Ac3 or above and to finish below Ms, and the temperature to decrease continuously with time. Very high cooling rates can be accounted for. Paraequilibrium Ac3, Bs and Ms temperatures are calculated for steel of the given composition. Two equivalent continuous cooling rates are considered, as averaged cooling rates at Ac3 and Bs and Bs and Ms.  All this information will then be passed on to the next submodels.

'Struct3.f' takes over and determines the extent of diffusive transformations occurring during cooling. This part of the model is a modified version of MAP_STEEL_STRUCTURE.  This information, together with the composition of the steel and the equivalent constant cooling rate during the displacive reactions are then passed on to 'bainite.f'.

'Bainite3.f' determines the extent of displacive phase transformations. For this model to be used in a wider range of steels, the original program 'bainite3.f' has been modified to include the special behaviour of low silicon steels in which the excess of carbon in austenite precipitates as carbides instead of enriching the remaining austenite as it happens with the high silicon steels.

Finally all the information calculated is collected and the final microstructure at room temperature is written in 'results.dat', and the phases volume fraction evolution over time saved in 'evolphse.dat'.

 
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References

  2. H. K. D. H. Bhadeshia and D. V. Edmonds, Acta Metallurgica, 28, (1980), 1265.

  3. H.K.D.H. Bhadeshia, Metal Science, 15, (1981), 175-177.

  4. H.K.D.H. Bhadeshia, Metal Science, 15, (1981), 178-180.

  5. H.K.D.H. Bhadeshia, Bainite in Steels, Institute of Materials, London, (1992), 1-454.

  6. R. H. Fowler and E. A. Guggenhiem, Statistical Thermodynamics, Cambridge University Press, New York,
(1939), 442.

  7. S.A. Khan and H.K.D.H. Bhadeshia, "Kinetics of martensitic transformation in partially bainitic 300M steel", Materials science and engineering, A129, (1990), 257-272
 
  8. J. R. Lacher, Proc. Cambridge Phil. Soc., 33, (1937), 518.

  9. J.A. Lobo and G.H. Geiger, Metallurgical Transactions, 7A, (1976), 1347 & 1359.

 10. S. J. Jones and H. K. D. H. Bhadeshia, "Kinetics of the Simultaneous Decomposition of Austenite into Several Transformation Products", Acta Materialia, Vol. 45, 1997, pp. 2911-2920.
 
 11. S. J. Jones and H. K. D. H. Bhadeshia, "Competitive Formation of Inter- and Intragranularly Nucleated Ferrite", Metallurgical and Materials Transactions A, Vol. 28A, 1997, 2005-2013.
 

 12. S. J. Jones and H. K. D. H. Bhadeshia , "Kinetics of the Widmanstatten Ferrite Transformation Displacive Phase Transformations and their Applications in Materials Engineering", eds K. Inoue, K. Mukherjee, K. Otsuka and H. Chen,The Minerals, Metals and Materials Society, Warrendale, Pennsylvania, U.S.A., (1998), 419-426.

 13. A.K. Seal and R.W.K. Honeycombe, J. Iron and Steel Institute, 188, (1958), 9-15
 
 14. A.K. Seal and R.W.K. Honeycombe, J. Iron and Steel Institute, 188, (1958), 343-350

 15. G.J. Shiflet, J.R. Bradley and H.I. Aaronsson, Metallurgical Transactions, 9A, (1978), 999.
 

 16. M.Takahashi and H.K.D.H. Bhadeshia, "A model for the microstructure of some advanced bainitic steels", Materials Transactions, JIM, 32, (1991), 689-696
 
 
 

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Parameters

Input parameters

temper.dat- file

            'temper.dat' is an optional file containing the cooling thermal history,in pairs time (s) temperature (oC).

compos.dat - file

            'compos.dat' if a file containing the composition of the steel in wt.% (carbon, silicon, manganese, nickel, molybdenum, chromium and vanadium).

grainsz.dat- file

            'grainsz.dat' is a file containing the equiaxed austenite grain size, in m.

Output parameters

results.dat - file

            'results.dat' is a file containing the volume fractions of ferrite, pearlite, bainite, martensite and retained austenite after the cooling process.

evolphse.dat - file

            'evolphse.dat' is a file containing the evolution of volume fractions of ferrite, pearlite, bainite, martensite and retained austenite during the cooling process.

Error Indicators

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Accuracy

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Further Comments

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Example

2. Program data

3. Program results

  Phases present after cooling/quench:
--------------------------------------
Volume fraction of:
  Ferrite                     0.0151
  Pearlite                    0.4998
  Bainite                     0.0000
  Martensite                  0.4568
  Retained austenite          0.0283
--------------------------------------
  Total                       1.0000
--------------------------------------

    Time /s Temperature /C    Vaus    Vferr   Vpearl  Vbain   Vmart   Vtot
     0.10      690.0         1.0000  0.0000  0.0000  0.0000  0.0000  1.0000
     0.21      669.6         1.0000  0.0000  0.0000  0.0000  0.0000  1.0000
     0.32      648.5         0.9994  0.0006  0.0000  0.0000  0.0000  1.0000
     0.44      626.4         0.9973  0.0027  0.0000  0.0000  0.0000  1.0000
    ...
     1.15      482.0         0.6271  0.0146  0.3583  0.0000  0.0000  1.0000
     1.18      475.8         0.6007  0.0147  0.3846  0.0000  0.0000  1.0000
     1.22      469.2         0.5752  0.0147  0.4101  0.0000  0.0000  1.0000
     1.26      462.5         0.5505  0.0148  0.4347  0.0000  0.0000  1.0000
     1.29      455.4         0.5274  0.0148  0.4578  0.0000  0.0000  1.0000
     1.33      448.1         0.5053  0.0151  0.4796  0.0000  0.0000  1.0000
     1.37      440.5         0.4851  0.0151  0.4998  0.0000  0.0000  1.0000
     2.21      280.8         0.4851  0.0151  0.4998  0.0000  0.0000  1.0000
     2.23      278.0         0.0283  0.0151  0.4998  0.0000  0.4568  1.0000
     3.55       25.0         0.0283  0.0151  0.4998  0.0000  0.4568  1.0000

Auxiliary Routines

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Keywords

Download

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