C*****************************************************************
C
        SUBROUTINE MAP_STEEL_OMEGA2(C,W,XBAR,T10,T20,ID)
C
C-----------------------------------------------------------------------------
C SUBROUTINE TO CALCULATE THE CARBON CARBON INTERACTION ENERGY IN
C AUSTENITE, AS A FUNCTION OF ALLOY COMPOSITION.  BASED ON .MUCG18
C THE ANSWER IS IN JOULES PER MOL.   **7 OCTOBER 1981**
C Feed in the alloy concentration in the following order
C  C    SI   MN   NI   MO   CR   V    CO   CU   AL    W    FE
C       In this Program first the Weight % is converted into Mol fraction
C Correction to P(11) by Mihai Tarcolea, June 2002
C----------------------------------------------------------------------------
C
C  1.   Y() contains only the at% of substitutional considering alone
C       T10 and T20 is calculated for the alloy concentration based on Y()
C  2.   Then C-C interaction (W) is calculated based on the ploynomials derived
C       Trial and Error for the interaction energies for Al and Cu
C       MODIFIED FOR OTHER ALLOYING ELEMENTS BY SURESH BABU - C - C APPROX
C       THE CARBON - CARBON INTERACTION MISSING FOR CU AND AL
C----------------------------------------------------------------------------
C
      IMPLICIT NONE
C
      DOUBLE PRECISION B1,B2,B3,T10,T20,W,XBAR
      DOUBLE PRECISION C(12), D(12), P(12), Y(12)
C
      INTEGER I,ID,IU,NCO
C
      B3=0.0D+00
      IF (ID .GE. 2) GOTO 110
      NCO = 12
      IF (NCO .GT. 12) THEN
        WRITE (6,*) '*** Error in MAP_STEEL_OMEGA2 ***'
        WRITE (6,*) ' Number of elements is greater than 12.'
        STOP
      ENDIF
      D(12)=C(1)+C(2)+C(3)+C(4)+C(5)+C(6)+C(7)+C(8)+C(9)+C(10)+C(11)
      D(12)=100.0D+00-D(12)
      D(12) =D(12)/55.84D+00
      D(1)  =C(1)/12.0115D+00
      D(2)  =C(2)/28.09D+00
      D(3)  =C(3)/54.94D+00
      D(4)  =C(4)/58.71D+00
      D(5)  =C(5)/95.94D+00
      D(6)  =C(6)/52.0D+00
      D(7)  =C(7)/50.94D+00
      D(8)  =C(8)/58.94D+00
      D(9)  =C(9)/63.54D+00
      D(10) =C(10)/26.98D+00
      D(11) =C(11)/183.85D+00
      B1=D(1)+D(2)+D(3)+D(4)+D(5)+D(6)+D(7)+D(8)+D(9)+D(10)+D(11)+D(12)
C------------------------
      DO 100 IU=1,12
        D(IU)=D(IU)/B1
100   CONTINUE
C------------------------
110   DO 120 IU=2,11
        Y(IU)=D(IU)/D(12)
120   CONTINUE
      XBAR=D(1)
      XBAR=DINT(10000.0D+00*XBAR)
      XBAR=XBAR/10000
C------------------------------------------------------------------------------
C       Delta T_nm and Delta T_mag were taken for Co from
C       Aaronson, Pound and Domain work - Trans.Met.Soc. AIME,
C       Vol.236 May, 1966, p. 769   (S. Babu, 18.7.1989)
C       C    SI   MN   NI   MO   CR   V    CO   CU   AL    W      FE
C       1    2    3    4    5    6    7    8    9    10    11     12
C------------------------------------------------------------------------------
      T10=Y(2)*(-3)+Y(3)*2+Y(4)*12+Y(5)*(-9)+Y(6)*(-1)+Y(7)*(-12)+
     &    Y(8)* 3.5 +Y(9)*7+Y(10)*(-7)+Y(11)*(-9)
C
C     T10 coefficients are actually Delt_mag - DelT_non.mag
C     T20 coefficients are actually Delt_mag
      T20=-  3*Y(2)-37.5*Y(3)-6*Y(4) -26*Y(5)-19*Y(6)-44*Y(7)+
     &    19.5*Y(8)- 4.5*Y(9)+8*Y(10)-26*Y(11)
C------------------------------------------------------------------------------
      P(2)=2013.0341D0+763.8167D0*D(2)+45802.87D0*D(2)**2-280061.63D0*
     &  D(2)**3+3.864D+06*D(2)**4-2.4233D+07*D(2)**5+6.9547D+07*D(2)**6
      P(3)=2012.067D0-1764.095D0*D(3)+6287.52D0*D(3)**2-21647.96D0*
     &  D(3)**3-2.0119D+06*D(3)**4+3.1716D+07*D(3)**5-1.3885D+08*D(3)**6
      P(4)=2006.8017D0+2330.2424D0*D(4)-54915.32D0*D(4)**2+1.6216D+06*
     &  D(4)**3-2.4968D+07*D(4)**4+1.8838D+08*D(4)**5-5.5531D+08*D(4)**6
      P(5)=2006.834D0-2997.314D0*D(5)-37906.61D0*D(5)**2+1.0328D+06*
     &  D(5)**3-1.3306D+07*D(5)**4+8.411D+07*D(5)**5-2.0826D+08*D(5)**6
      P(6)=2012.367D0-9224.2655D0*D(6)+33657.8D0*D(6)**2-566827.83D0*
     &  D(6)**3+8.5676D+06*D(6)**4-6.7482D+07*D(6)**5+2.0837D+08*D(6)**6
      P(7)=2011.9996D0-6247.9118D0*D(7)+5411.7566D0*D(7)**2
     &  +250118.1085D0*D(7)**3-4.1676D+06*D(7)**4
C------------------------------------------------------------------------------
C           CO  CU   AL    W      FE
C           8   9    10    11     12
C           EFFECT TAKEN FROM HKDB - MET.SCI - 1981
C           RESULT IN J/MOLE    (S. Babu, 18.7.1989)
C           W SAME AS MOLYBDENUM  IN INTERACION ENERGY
C------------------------------------------------------------------------------
      P(8)=(8427.00D0+5986D0*D(8))/4.187D0
      P(9)=  2011.0D0
      P(10)= 2011.0D0
      P(11)= 2006.834D0-2997.314D0*D(11)-37906.61D0*D(11)**2+1.0328D+06*
     &  D(11)**3-1.3306D+07*D(11)**4+8.411D+07*D(11)**5-2.0826D+08*D(11)**6
      B2=0.0D+00
      DO 130 IU=2,11
        B3=B3+P(IU)*Y(IU)
        B2=B2+Y(IU)
130   CONTINUE
      IF (DABS(B2) .LT. 1D-40) THEN
        W=8054.0D0
      ELSE
        W=(B3/B2)*4.187
      ENDIF
      IF (DABS(B3) .LT. 1D-40)THEN
        W = 8054.0D0
      ENDIF
      DO 140 I = 1, 12
        C(I) = D(I)
140   CONTINUE
      RETURN
      END
C
C----------------------------------------------------------------------------