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H.K.D.H. Bhadeshia and N.A. Chester,

Phase Transformations Group,

Department of Materials Science and Metallurgy,

University of Cambridge,

Cambridge, U.K.

To calculate the martensite-start temperature.

Language: | FORTRAN |

Product form: | Source code |

SUBROUTINE MAP_STEEL_MSTART(T10,T20,W,W1,JTLOW,JTHIGH,MS,X1,JP)

DOUBLE PRECISION DCTEMP(100), FTO(100)

DOUBLE PRECISION AJ, AJ1, CONST, CORR, F, H, H1,

& KTEMP, MS, R, S, S1, SLOPE, T10, T20,

& W, W1, XTO, X1, XMS

DOUBLE PRECISION MAP_STEEL_ENERGY, MAP_STEEL_FTO1

INTEGER J, J1, J2, JP, JTLOW, JTHIGH,

& IL, ITLOW, ITHIGH, IT

MAP_STEEL_MSTART calculates the martensite-start temperature using theory based on [3]. This is also used in subroutine MAP_STEEL_BSMS, which calculates both Bs and Ms temperatures.

If the free energy of transformation from austenite to ferrite Delta G^{{gamma alpha}} in pure iron is factorised into magnetic and non-magnetic components, then Delta TM and Delta TNM represent the temperature changes, caused by unit concentration x of substitutional solute, to the temperature
at which Delta G^{{gamma alpha}} is calculated.

- G.J. Shiflet, J.R. Bradley and H.I. Aaronsson, Metallurgical Transactions A,
__9A__, (1978), 999. - J.A. Lobo and G.H. Geiger, Metallurgical Transactions A,
__7A__, (1976), 1357 and 1359. - H.K.D.H. Bhadeshia, Metal Science,
__15__, (1981), 175-180.

**T10**- double precision- T10 = Delta TM - Delta TNM
**T20**- double precision- T20 = Delta TM
**W**- double precision- W is the carbon-carbon interaction energy in austenite (in joules per
mole, Jmol
^{-1}). **W1**- double precision- W1 is the carbon-carbon interaction energy in ferrite (in joules per
mole, Jmol
^{-1}). **JTLOW**- integer- JTLOW is the lowest temperature (in kelvin) for which results are to be
calculated.
**JTHIGH**- integer- JTHIGH is the highest temperature (in kelvin) for which results are to
be calculated.
**X1**- double precision- X1 is the carbon concentration (in mole fraction).
**JP**- integer- JP defines the amount of printing in subroutines called by this
subroutine. A value of 1 means no printing.

**MS**- double precision- MS is the martensite-start temperature (in degrees centigrade).

None.

No information supplied.

None.

PROGRAM MSTART IMPLICIT NONE DOUBLE PRECISION T10,T20,W,W1,MS,X1 INTEGER JTLOW,JTHIGH,JP C OPEN(3,FILE='data.dat') C R = 8.3143D+00 C READ(3,*) T10 READ(3,*) T20 READ(3,*) W READ(3,*) W1 READ(3,*) JTLOW READ(3,*) JTHIGH READ(3,*) X1 READ(3,*) JP C CALL MAP_STEEL_MSTART(T10,T20,W,W1,JTLOW,JTHIGH,MS,X1,JP) C WRITE(6,1001) MS C CLOSE(3) STOP 1001 FORMAT('MS is ',f6.2) END

-4.32D-02 -0.762 8488.89 48570 473 773 1.74D-02 1

MS is 320.34

**Functions**:

MAP_STEEL_ENERGY

MAP_STEEL_FTO1

**Utility Subroutines**:

MAP_UTIL_ANALY

martensite, start temperature

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