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  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

H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

Added to MAP: June 1999.

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To calculate the ferrite lattice parameter at room temperature of an alloy steel.

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Product form:Source code



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MAP_STEEL_FERR is used in the analysis of the transformation from austenite to ferrite. It calculates the lattice parameter of the ferrite phase at room temperature (25°C), using equation 1 in reference 1, given the mean concentrations of C, Si, Mn, Ni, Mo, Cr and V in the material and the C concentration in the ferrite:

a (nm) = aFe + [(aFe-0.0279xC)2.(aFe+0.2496xC)-aFe3]/(3.aFe2) - 0.003xSi + 0.006xMn
+ 0.007xNi + 0.031xMo + 0.005xCr + 0.0096xV

where xi is the mole fraction of element i in the ferrite and aFe (nm) is the lattice parameter of pure iron at room temperature. The concentrations of the solute elements other than C are assumed to be evenly distributed between the phases. The effect of molybdenum is derived from reference 2, the vanadium coefficient is from reference 3 and the expansion due to carbon is taken from reference 4. A value of 2.8664 Å for pure iron is given by reference 5.

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  1. H.K.D.H Bhadeshia, S.A. David, J.M. Vitek and R.W. Reed, 1991, Materials Science and Technology, 7, 686-698.
  2. F. Wever, 1928, Zeitschrift für Metallkunde, 20, 363-370.
  3. Hume-Rothery and Sutton, Structure of Iron and Alloys.
  4. C.S. Roberts, 1953, Trans. AIME, 197, 203.
  5. National Bureau of Standards (USA), 1955, Circ. 539, 43.

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Input parameters

C - real
C is the mean carbon concentration (weight percent) of the material.

SI - real
SI is the silicon concentration (weight percent).

MN - real
MN is the manganese concentration (weight percent).

NI - real
NI is the nickel concentration (weight percent).

MO - real
MO is the molybdenum concentration (weight percent).

CR - real
CR is the chromium concentration (weight percent).

V - real
V is the vanadium concentration (weight percent).

CALP - real
CALP is the concentration of carbon dissolved in ferrite (weight percent).

PFE - real
PFE is the lattice parameter of pure iron at room temperature (metres). Reference 5 gives a value of 2.8664 Å.

Output parameters

P - real
P is the ferrite lattice parameter at 298K (metres).

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Error Indicators


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No information supplied.

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Further Comments

The remaining wt.% of the steel is assumed to be iron. The calculations of the solute atom concentrations assume that the C concentration is small.

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1. Program text

      PFE = 2.8664D-10
      WRITE(*,*) 'Input C  Si  Mn  Ni  Mo  Cr  V  wt%:'
      READ (*,*) C,SI,MN,NI,MO,CR,V
      WRITE(*,*) 'Input C concentration dissolved in ferrite (wt%):'
      READ (*,*) CALP
      P = P * 1D10
      WRITE (*,1) P
    1 FORMAT ('Ferrite lattice parameter at 298K = ',F8.5,' Angstroms')

2. Program data

 Input C  Si  Mn  Ni  Mo  Cr  V  wt%:
     0.05 0.5  1   0   0 0.01 0
 Input C concentration dissolved in ferrite (wt%):

3. Program results

Ferrite lattice parameter at 298K =  2.86731 Angstroms

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Auxiliary Routines


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ferrite, lattice parameter

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Download source code

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