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Program MAP_STEEL_MS

  1. Provenance of code.
  2. Purpose of code.
  3. Specification.
  4. Description of subroutine'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

Tracey Cool*,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

*TC is now with the Materials Engineering Department, Parsons Power Generation Systems Ltd, Heaton Works, Shields Road, Newcastle Upon Tyne, NE6 2YL

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Purpose

To estimate the MS temperature of an alloy steel as a function of the free energy, calculated from the chemical composition.

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Specification

Complete program.

Language:FORTRAN
Product form:Source code

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Description

The program reads in the chemical composition of a steel and thermodynamic results from MTDATA, calculated for a steel of the same composition. It is used here to predict the free energy of austenite, and of ferrite of the same composition, over a range of temperatures. The program calculates the free energy due to the composition of the steel after Ghosh and Olson [2, 3], and the free energy chance for the austenite -> ferrite transformation over the temperature range, including a Zener ordering term. Equating these two values allows the martensite-start temperature to be calculated.

Initial composition, temperature and free energy values are read from a data file, default name ms-profile.dat

MTDATA is a computer based package used for thermodynamic predictions, and is a trademarked product of the National Physical Laboratory.[5]

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References

  1. T. Cool, PhD Thesis, University of Cambridge, 1996
  2. G. Ghosh and G.B. Olson, Proceedings of ICOMAT '92, International Conference on Martensitic Transformations, Monterey Institute for Advanced Studies, California, U.S.A. 353-358, 1993
  3. G. Ghosh and G.B. Olson, Acta Metallurgica et Materialia, 42 3361-3370, 1994
  4. T. Cool and H.K.D.H. Bhadeshia, Materials Science and Technology, 12 40-44, 1996
  5. MTDATA, Metallurgical Thermochemistry and Thermodynamic Database, National Physical Laboratory, Teddington, U. K., 1996

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Parameters

Input parameters

Note that input parameters are read from a data file, default name ms-profile.dat

J6 - integer
Identification number for the alloy

C(1) - double precision
Carbon composition in weight%. 0<C(1)<2%

C(2) - double precision
Silicon composition in weight%. 0<C(2)<3.5

C(3) - double precision
Manganese composition in weight%. 0<C(3)<5

C(4) - double precision
Nickel composition in weight%. 0<C(4)<6

C(5) - double precision
Molybdenum composition in weight%. 0<C(5)<5.6

C(6) - double precision
Chromium composition in weight%. 0<C(6)<15.5

C(7) - double precision
Vanadium composition in weight%. 0<C(7)<1.8

C(8) - double precision
Copper composition in weight%. 0<C(8)<1.5

C(9) - double precision
Tungsten composition in weight%. 0<C(9)<18

C(10) - double precision
Niobium composition in weight%. 0<C(10)<1.5

C(11) - double precision
Nitrogen composition in weight%. 0<C(11)<1.5

C(12) - double precision
Cobalt composition in weight%. 0<C(12)<3.5

Y - double precision
Experimental MS value in °C. If no value is available, a zero is requested as an input.

J7 - integer
The number of temperatures at which the free energies of austenite and ferrite have been calculated using MTDATA. Work in [1] has used 25 temperatures at 25°C intervals.

T(n) - double precision array
The temperature(s) in Kelvin at which MTDATA has been run. n = 1-J7

D(n) - double precision array
The ferrite free energies (in J/kg) at the corresponding temperatures, T(n). These are determined from MTDATA by allowing only the ferrite phase to exist at the range of temperatures.

E(n) - double precision array
The austenite free energies (in J/kg) at the corresponding temperatures, T(n). These are determined from MTDATA runs at the same temperatures, allowing only the austenite phase to exist.

Output parameters

FE - double precision
Predicted free energy due to composition [2,3] with K1 = 1010 kJmol-1 (new value).

L1 - double precision
MS predicted from the free energy (new K1) without consideration of the Zener ordering term.

L2 - double precision
MS predicted from the free energy (new K1) with inclusion of the Zener ordering term.

FFE - double precision
Predicted free energy due to composition [2,3] with K1 = 683 kJmol-1 (old value).

L3 - double precision
MS predicted from the free energy (old K1) without consideration of the Zener ordering term.

L4 - double precision
MS predicted from the free energy (old K1) with inclusion of the Zener ordering term.

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Error Indicators

A warning is returned if the user attempts to enter an invalid composition. The user is prompted to re-supply the value.

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Accuracy

No information supplied.

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Further Comments

The data file ms-profile.dat is configured as follows :- 

Row  1   J6
Row  2   C(1)
Row  3   C(2)
Row  4   C(3)
Row  5   C(4)
Row  6   C(5)
Row  7   C(6)
Row  8   C(7)
Row  9   C(8)
Row 10   C(9)
Row 11   C(10)
Row 12   C(11)
Row 13   C(12)
Row 14   Y
Row 15   J7
Row 16   T(1), D(1), E(1)
Row 17   T(2), D(2), E(2)
.
.
.
Row  n   T(n), D(n), E(n)

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Example

1. Program text

       Complete program

2. Program data

Example of contents of ms-profile.dat 

1
0.08
0.43
1.02 
2.23 
0.71 
1.86 
0.01 
0.03 
0 
0.008 
0.01 
0 
0 
25 
973.0000, -7.8159414481E+05, -7.8112221055E+05
948.0000, -7.5085427769E+05, -7.4897941982E+05
923.0000, -7.2071918466E+05, -7.1721440685E+05
898.0000, -6.9117439454E+05, -6.8583476688E+05
873.0000, -6.6220894490E+05, -6.5484851561E+05
848.0000, -6.3381478019E+05, -6.2426412408E+05
823.0000, -6.0598629400E+05, -5.9409055753E+05
798.0000, -5.7871998519E+05, -5.6433731864E+05
773.0000, -5.5201420414E+05, -5.3501449600E+05
748.0000, -5.2586897107E+05, -5.0613281854E+05
723.0000, -5.0028585226E+05, -4.7770371666E+05
698.0000, -4.7526788374E+05, -4.4973939142E+05
673.0000, -4.5081953488E+05, -4.2225289286E+05
648.0000, -4.2694670623E+05, -3.9525820922E+05
623.0000, -4.0365675818E+05, -3.6877036873E+05
598.0000, -3.8095856840E+05, -3.4280555638E+05
573.0000, -3.5886261742E+05, -3.1738124832E+05
548.0000, -3.3738110299E+05, -2.9251636733E+05
523.0000, -3.1652808518E+05, -2.6823146333E+05
498.0000, -2.9631966529E+05, -2.4454892401E+05
473.0000, -2.7677420306E+05, -2.2149322170E+05
448.0000, -2.5791257808E+05, -1.9909120393E+05
423.0000, -2.3975850300E+05, -1.7737243695E+05
398.0000, -2.2233889775E+05, -1.5636961299E+05
373.0000, -2.0568433547E+05, -1.3611903445E+05

3. Program results

Composition of sample  1
  Element        C      Si      Mn      Ni      Mo      Cr       V      Cu       W      Nb       N      Co      Fe
     Wt%    0.0800  0.4300  1.0200  2.2300  0.7100  1.8600  0.0100  0.0300  0.0000  0.0080  0.0100  0.0000 93.6120
At fract.   0.0037  0.0085  0.0103  0.0211  0.0041  0.0199  0.0001  0.0003  0.0000  0.0000  0.0004  0.0000  0.9316
              700. Centigrade              -26.41 J/mol
              675. Centigrade             -104.92 J/mol
              650. Centigrade             -196.13 J/mol
              625. Centigrade             -298.81 J/mol
              600. Centigrade             -411.90 J/mol
              575. Centigrade             -534.46 J/mol
              550. Centigrade             -665.69 J/mol
              525. Centigrade             -804.86 J/mol
              500. Centigrade             -951.32 J/mol
              475. Centigrade            -1104.45 J/mol
              450. Centigrade            -1263.71 J/mol
              425. Centigrade            -1428.59 J/mol
              400. Centigrade            -1598.61 J/mol
              375. Centigrade            -1773.31 J/mol
              350. Centigrade            -1952.27 J/mol
              325. Centigrade            -2135.07 J/mol
              300. Centigrade            -2321.33 J/mol
              275. Centigrade            -2510.66 J/mol
              250. Centigrade            -2702.72 J/mol
              225. Centigrade            -2897.13 J/mol
              200. Centigrade            -3093.57 J/mol
              175. Centigrade            -3291.69 J/mol
              150. Centigrade            -3491.17 J/mol
              125. Centigrade            -3691.69 J/mol
              100. Centigrade            -3892.93 J/mol
 
***NEW K1***
Predicted free energy due to comp =    -1783.1726231491 J/mol
 
 
Without Zener ordering
 
          Ms (new) approximately     374. Centigrade
 
With Zener ordering
 
          Ms (new) approximately     374. Centigrade
 
***OLD K1***
Predicted free energy due to comp =    -2109.8726231491 J/mol
  
 
Without Zener ordering
 
          Ms (old) approximately     328. Centigrade
 
With Zener ordering
 
          Ms (old) approximately     328. Centigrade
 
No experimental data was provided for comparison

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Auxiliary Routines

MAP_UTIL_REED
MAP_UTIL_REEDI

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Keywords

martensite transformation, martensite, start temperature, steel

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Download

Download source code

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MAP originated from a joint project of the National Physical Laboratory and the University of Cambridge.

MAP Website administration / map@msm.cam.ac.uk

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