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Program MAP_STEEL_TR

  1. Provenance of code.
  2. Purpose of code.
  3. Specification.
  4. Description of program's operation.
  5. References.
  6. Parameter descriptions.
  7. Error indicators.
  8. Accuracy estimate.
  9. Any additional information.
  10. Example of code
  11. Auxiliary routines required.
  12. Keywords.
  13. Download source code.
  14. Links.


Provenance of Source Code

C. Capdevila and H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge CB2 3QZ, U.K.

E-mail: cc226@cus.cam.ac.uk

Added to MAP: October 2000.

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Purpose

The recrystallisation behaviour of PM2000 oxide dispersion strengthened ferritic alloy has been investigated for samples which were cold deformed after extrusion. This program deals with the evolution of the recrystallisation temperature TR, defined as the minimum temperature at which the sample begins to recrystallise during heat treatment for one hour, as a function of the level of deformation and the heating rate.

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Specification

Language:

Fortran 77

Product form:

Source code

Complete program.

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Description

PM2000 is an iron-base superalloy designed for power plant applications, strengthened with yttria particles [1]. It is manufactured by mechanical alloying [2], in which elemental powders or compounds are heavily deformed while in intimate contact, to such large strains that the mechanical mixture of powders changes into a solid solution, with the exception of the yttrium oxide particles which are dispersed uniformly. The alloyed powder is then canned and hot extruded; the microstructure at this stage consists of incredibly fine (0.5 micrometers) equiaxed [3]. Subsequent annealing at exceptionally high temperatures, of the order of 0.9 of the melting temperature, yields recrystallised grains which are columnar and aligned along the extrusion direction giving excellent creep strength along the tube axis. The columnar growth is primarily a consequence of the alignment of oxide particles along the extrusion direction. However, in pressurised tubes, the maximum principal stress is in the hoop direction where the tubes are weakest in creep. To improve the hoop strength, tubes are deformed in torsion prior to heat treatment, in order to recrystallise the material into a helical grain structure which follows the twisted alignment of the oxide particles [4,5].

Calculations using the model and experimental values obtained for PM2000 illustrate the variation in TR as a function of heating rate and of the deformation level. A comparison between calculated and predicted results is presented in Fig. 1. The results confirm that recrystallisation can be expected to occur at higher temperatures as deformation becomes more uniform. Furthermore, the increase of TR with the heating rate is more important at about 50% in reduction in area, when deformation is most heterogeneous.

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References

  1. D. Sporer and G. Korb, Procc. Of the 2nd International Conference on Structural Applications of Mechanically Alloying, Vancouver, British Columbia, Canada, (1993), p.109.
  2. J. S. Benjamin, Metall. Trans., 1, (1970), p.2943.
  3. D. Sporer and K. Lempenauer, Proceedings of 13th International Plansee Seminar, Eds. H. Bildstein and R. Eck, Metallwerk Plansee, Reutte, (1993), p.796.
  4. D.M. Jaeger and A.R. Jones, Proc. Conf. 'Materials for Advanced Power Engineering', Liege, Ed.: Coutsouradis et al., Kluwer Academic, (1993), 1994), p. 1515.
  5. D.M. Jaeger and A.R. Jones, Proc. Conf. 'Materials for Advanced Power Engineering', Liege, Ed.: Coutsouradis et al., Kluwer Academic, (1993), 1994), p. 1507.

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Parameters

Input parameters

HR - Double precision
Heating Rate (oC/min).
TM - Double precision
Isothermal Melting Temperature (oC)

Output parameters

CTEMP - Double precision
TR temperature (oC).
RECRYS - Double Precision
Vol. Fraction. Recrystallised.
IDEF- Double Precision
Level of Deformation (%).

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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

Complete program.

2. Program data


TM=1482 oC

3. Program results

Temperature

Frac. Recrys.

Deformation Level

1378

0.502838E-01

0

1178.

0.523008E-01

10

1018.

0.518034E-01

20

906.

0.510580E-01

30

846.

0.529337E-01

40

834.

0.559039E-01

50

866.

0.540186E-01

60

946.

0.518452E-01

70

1074.

0.512006E-01

80

1244.

0.517920E-01

90

 

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Auxiliary Routines

none

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Keywords

ODS, Ferritic Steel, Steel, Recrystallisation

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Download

Download source code

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

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