Materials Algorithms Project
Program Library

Subroutine MAP_STEEL_SOL_BOR

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

S.J. Jones^* and H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

^*Dr S.J. Jones is now with Ford Motor Co. (UK) Ltd

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Purpose

To calculate the soluble boron, soluble nitrogen and boron nitride content of austenite at any temperature.

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Specification

 SUBROUTINE MAP_STEEL_SOL_BOR(BATM,BWT,NITATM,NITWT,NIT2,TEMPC,
& BSOL,BWTSOL,NITSOL,NITWTSOL,NITB,BNIT)

 IMPLICIT NONE

 DOUBLE PRECISION BATM,BWT,NITATM,NIT2,NITWT,TEMPC,
& BSOL,BWTSOL,NITSOL,NITWTSOL,NITB,BNIT,NIT3,CONST,
& BWTSOLMAX,SOLPRODCON,DIFBATMNIT2,SQROOT,NIT3A,NIT3B

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Description

If there is only boron, all of this is assumed to remain in solution, whilst if there is only residual nitrogen (that nitrogen present after reacting with titanium to form TiN), all of this is assumed to remain in solution.

If both residual nitrogen and boron are present, then a solubility product is used to determine whether all the boron and nitrogen can remain in solution. This is determined by assuming that all the residual nitrogen enters solution and calculating the maximum possible soluble boron concentration. This is then compared with the actual boron concentration.

If the actual boron concentration is less than the maximum calculated, then all the boron and all the residual nitrogen can be remain in solution simultaneously. However, if the actual boron concentration is greater than the maximum calculated, then all the boron and the residual nitrogen cannot remain in solution simultaneously and boron nitride will precipitate. By assuming that the stoichiometry of this is represented by BN then it is possible to calculate the soluble boron by determining the positive root of the following equation which is constructed using the solubility product due to Maitrepierre et al. [2]:-

where :-

B_T^mol is the total number of moles of boron per unit mass of steel,

N_res^mol is the number of moles of residual nitrogen per unit mass of steel and

B_S^mol is the number of moles of soluble boron per unit mass of steel.

F_X denotes the factors used to convert the units of the species boron and nitrogen from wt. % to moles per unit mass of steel.

The number of moles of boron per unit mass of steel forming BN is therefore given by mass balance as :-

The number of moles of soluble nitrogen per unit mass of steel is thus :-

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References

1. S.J. Jones, PhD Thesis, University of Cambridge 1996.
2. Ph. Maitrepierre, J. Rofes-Vernis and D. Thivellier, "Structure-properties Relationships in Boron Steels", Boron in Steels, Proc. of the Metallurgical Society of AIME, Milwaukee, 1-19 1979.

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Parameters

Input parameters

BATM - real

BATM is the total number of moles of boron per 100 grams of austenite.

BWT - real

BWT is the total boron concentration (wt. %).

NITATM - real

NITATM is the total number of moles of nitrogen per 100 grams of austenite.

NITWT - real

NITWT is the total nitrogen concentration (wt. %).

NIT2 - real

NIT2 is the number of moles of residual nitrogen (after TiN formation) per 100 grams of austenite.

TEMPC - real

TEMPC is the temperature at which the solubility product is to be evaluated (°C).

Output parameters

BSOL - real

BSOL is the number of moles of soluble boron per 100 grams of austenite.

BWTSOL - real

BWTSOL is the soluble boron concentration (wt. %).

NITSOL - real

NITSOL is the number of moles of soluble nitrogen per 100 grams of austenite.

NITWTSOL - real

NITWTSOL is the soluble nitrogen concentration (wt. %).

BNIT - real

BNIT is the number of moles of boron combined with nitrogen per 100 grams of austenite.

NITB - real

NITB is the number of moles of nitrogen combined with boron per 100 grams of austenite.

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Error Indicators

None.

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Accuracy

No information supplied.

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Further Comments

None.

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Example

1. Program text

       PROGRAM MAP_STEEL_SOL_BOR
       IMPLICIT NONE
C
       DOUBLE PRECISION BATM,BWT,NITATM,NIT2,NITWT,TEMPC,
     & BSOL,BWTSOL,NITSOL,NITWTSOL,NITB,BNIT
C
       READ(*,*) BATM,BWT,NITATM,NITWT,NIT2,TEMPC
C
       CALL MAP_STEEL_SOL_BOR(BATM,BWT,NITATM,NITWT,NIT2,
     & TEMPC,BSOL,BWTSOL,NITSOL,NITWTSOL,NITB,BNIT)
C
       WRITE(*,10) BSOL,BWTSOL,NITSOL,NITWTSOL,NITB,BNIT
10     FORMAT(E10.3,1X,E10.3,1X,E10.3,1X,E10.3,1X,E10.3,1X,E10.3)
C
       STOP
C
       END

2. Program data

0.370E-5  0.400E-2  0.357E-5  0.500E-2  0.250E-2  0.940E3

3. Program results

 0.126E-08  0.136E-05  0.250E-02  0.350E+01  0.370E-05  0.370E-05

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Auxiliary Routines

None.

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Keywords

solubility product, boron, nitrogen, austenite, steel, boron nitride, temperature

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Download

Download source code

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