Materials Algorithms Project
Program Library
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Materials Algorithms Project
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Sangeeta Khare
Graduate Institute of Ferrous Technology (GIFT)
Pohang University of Science and Technology (POSTECH)
Pohang 790-784
Republic of Korea
E-mail: skhare@postech.ac.kr
Added to MAP: March 2009.
The program calculates the soluble boron in a steel containing of titanium, aluminium, nitrogen and boron using solubility product equations of nitrides.
| Language: | Fortran |
| Product form: | Source code |
Complete program.
Soluble boron in a steel containing titanium, aluminium, nitrogen and boron is calculated by stepwise approach which is based on the solubility product of various nitrides under equilibrium conditions. Nitrogen combines with that element which forms first according to solubility product equations [1-4]. The temperature at which precipitate form is calculated by assuming total nitrogen can combine with Ti, Al or B and these temperatures are given as T°TiN, T°AlN and T°BN.
It assumes that Ti, Al & B form nitrides only and are in an equilibrium state and follow solubility product equations as
log [Ti][N] = -15790 T-1 + 5.4
log [Al][N] = -7400 T-1 + 1.95
log [B][N] = -13970 T-1 + 5.24
where the temperatures are in Kelvin and the terms in square brackets represent dissolved solute concentration in wt%.
From mass balance,
Ti = TiTiN + [Ti]
Al = AlAlN + [Al]
B = BBN + [B]
In general, M = [M] + MMN where 'M' stands for a metal atom and MMN is the amount of that metal atom tied up with nitrogen and the total nitrogen is N = [N] + NTiN + NAlN + NBN.
By solving the above equations as described in [1], the residual nitrogen can be calculated. The residual nitrogen is then available for the next of two elements to form nitride and accordingly it will combine with the next metal atom forming at the next higher temperature till any residual nitrogen left otherwise the process stops and soluble boron can be determined.
The program requires four elements namely titanium, boron, aluminium and nitrogen (all in wt%) to be supplied.
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Input order |
Element |
Min.(wt%) | Max.(wt%) |
| 1 | Titanium | 0.0 | 0.05 |
| 2 | Boron | 0.0 | 0.005 |
| 3 | Aluminium | 0.0 | 2.0 |
| 4 | Nitrogen | 0.0 | 0.020 |
The output gives temperature at which each precipitate forms T°TiN, T°AlN and T°BN by allowing whole of nitrogen to combine with Ti, Al and B and the soluble boron at 920 °C in the steel.
The maximum number of alloys that can be examined is set to be 10.
T. Gladman. The Physical Metallurgy of Microalloyed Steels. IOM Communications, London, 1996.
E. T. Turkdogan. Causes and effects of nitride and carbonitride precipitation during continuous casting. Iron Steelmaker, 3 : 61-75, 1989.
L.S. Darken, R.P. Smith and E.W. Filer, Solubility of Gaseous Nitrogen in Gamma Iron and the Effect of Alloying Constituents-Aluminium Nitride Precipitation. Trans AIME. 191 :1174-1179 (1951).
W. Fountain and J. Chipman. Solubility and precipitation of boron nitride in Fe-B alloys. Trans. TMS-AIME, 224 :599-606, 1962.
Allowable range ( see description)
No information supplied.
None.
Complete program.
Identification Number ?
(zero to exit program)
1
Titanium wt.% ?
0.01
Boron wt.% ?
0.0028
Aluminium wt.% ?
0.003
Nitrogen wt.% ?
0.0050
3. Program results
*********************************************************************
Titanium = 0.0100 wt%
Boron = 0.0028 wt%
Aluminium = 0.0030 wt%
Nitrogen = 0.0050 wt%
*********************************************************************
Temperature for TiN = 1350.C
Temperature for BN = 1110.C
Temperature for AlN = 815.C
*********************************************************************
Soluble Boron = 13.9 ppm at 920C
*********************************************************************
Subroutines
MAP_SOLUBLE_BORON_CALCULATION
MAP_BN_SOLUBILITY
MAP_TIN_SOLUBILITY
MAP_ALN_SOLUBILITY
MAP_BORON_NITROGEN_ARRAY
MAP_BN_TEMPERATURE
MAP_TIN_TEMPERATURE
MAP_ALN_TEMPERATURE
MAP_CHECK_NITROGEN
MAP_BORON_SOLUBLE
MAP_BOUND
Soluble boron, titanium, aluminium, nitrogen, solubility product.