H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.
To calculate the martensite and bainite start-temperatures.
Language: | FORTRAN |
Product form: | Source code |
MAP_STEEL_BSMS calculates the martensite-start and bainite-start temperatures. The bainite-start temperature is calculated on the growth condition alone. It is defined by the point where the driving force for diffusionless transformation exceeds the stored energy of bainite. A linear regression of the free energy change, for the transformation of austenite to ferrite of the same chemical composition, as a function of the temperature is obtained. From this the bainite start energy is calculated, assuming that the stored energy is 400 J/mol [3]. The calculation of the martensite start temperature is based on the thermodynamics of martensitic transformations in plain carbon steels given in references 4 and 5. Also given are the slopes and intercepts of the To and To' lines in the phase diagram. The To line is the locus of all temperatures at which austenite and ferrite of the same composition have identical free energies. The To' line is the same as the To line except that the stored energy of ferrite is increased by a specified amount, in this case 400 J/mol.
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 of substitutional solute, to the temperature at which Delta G{gamma alpha} is calculated. These quantities are functions of the substitutional solute content of the alloy and can be calculated using subroutine MAP_STEEL_OMEGA
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No information supplied.
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DOUBLE PRECISION T10,T20,W,W1,X1,BS,MS,XTOSL,XTOCN,XTOSL2,XTOCN2 DOUBLE PRECISION R INTEGER JTLOW,JTHIGH,JT C C R is the molar gas constant (in joules per mole per kelvin, J/(mol K)) C R=8.31451D+00 C WRITE(*,*) WRITE(*,*) 'Input T10, T20, W, W1, X1:' READ (*,*) T10,T20,W,W1,X1 WRITE(*,*) WRITE(*,*) 'Input lowest T, highest T, T interval (K):' READ (*,*) JTLOW, JTHIGH, JT CALL MAP_STEEL_BSMS(T10,T20,W,W1,JTLOW,JTHIGH,JT, & BS,MS,X1,XTOSL,XTOCN,XTOSL2,XTOCN2,R) WRITE (*,10) BS WRITE (*,20) MS WRITE (*,30) XTOSL, XTOCN WRITE (*,40) XTOSL2, XTOCN2 STOP 10 FORMAT (//'Bainite-start temperature = ',F8.2, ' deg. C') 20 FORMAT ('Martensite-start temperature = ',F8.2, ' deg. C') 30 FORMAT (/'To line: slope = ',D12.5,', intercept = ',D12.5) 40 FORMAT ('To-prime line: slope = ',D12.5,', intercept = ',D12.5/) END
Input T10, T20, W, W1, X1: -0.0097 -0.42 8414.5 48570 0.032 Input lowest T, highest T, T interval (K): 473 873 40
Bainite-start temperature = 386.47 deg. C Martensite-start temperature = 213.62 deg. C To line: slope = -0.15081D-03, intercept = 0.10355D+00 To-prime line: slope = -0.13788D-03, intercept = 0.85872D-01
Subroutines
MAP_UTIL_ANALY
MAP_STEEL_AXTO
Functions
MAP_STEEL_ENERGY
MAP_STEEL_FTO1 (called by MAP_STEEL_AXTO)
MAP_STEEL_G91 (called by MAP_STEEL_AXTO)
martensite, bainite, start-temperature
MAP originated from a joint project of the National Physical Laboratory and the University of Cambridge.
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