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Provenance of Source Code

Pieter van der Wolk
Heat Treatment Science and Technology Group
Laboratory of Materials Science
Delft University of Technology
Rotterdamseweg 137
2628 AL Delft

Contact: P.J.vanderWolk@STM.TUDelft.nl

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Provides a database giving Ms data for steels of various composition, and a trained neural network model (provided as a spreadsheet) for calculating Ms temperatures for steels of arbitrary composition.

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The distribution contains three types of file, as described :-

  1. neur-ms.txt is a text version of this document.
  2. MS.TXT is an tab-delimited ASCII text file containing a database of steel compositions and their martensite start temperatures. Each row represents one steel composition. Columns are :-

    Columns 1 and 2 give the Ac3 temperature and the austenising temperature respectively (in Kelvin).
    Columns 3-19 specify alloying element in mass%. The elements are :-

    Alloying elements which were not specified in the original paper have been set to zero.

    Column 20 gives Martensite start temperature in Kelvin.
    Column 21 gives a reference number; the meaning of these reference numbers is listed at the bottom of the file, and in the reference list below.

  3. MsANN.WK1 and MsANN.xls contain a neural network model converted into LOTUS1-2-3 and EXCEL3 formats respectively.

    After editing the cells with the alloying elements (B5..B16) the Ms-temperature (F8..F10) is updated automatically according to the neural network model. The model is incorporated in the spreadsheet below row 18.

    The neural network model has been trained with 311 steel compositions from the above database; 233 data have been used to calibrate the model, and 78 data have been used to validate the model.

    It is a hierarchical feed-forward backpropagating neural network with a 12:5:1 architecture. For a detailed description, see [5].

    Testing the model

    The initial steel composition gives :-

    Constituent Mass% Ms Temp (Kelvin)
    C 0.2000 718.0
    Si 0.2500
    Mn 0.7000
    P 0.0010
    S 0.0005
    Ni 0.1000
    Cr 0.3500
    Mo 0.0100
    V 0.0000
    Cu 0.0000
    Al 0.0200
    N 0.0050

    If the following compositions give the indicated Ms temperatures, the model is working properly.

    Constituent Mass%
    Ms Temp (Kelvin)
    Ms Temp (Kelvin)
    C 0.6000 523.3 0.1100 722.6
    Si 0.4800 1.0000
    Mn 1.6100 0.5000
    P 0.0140 0.0000
    S 0.0280 0.0000
    Ni 0.0500 0.9000
    Cr 1.0000 0.0300
    Mo 0.0200 0.1000
    V 0.1600 0.0000
    Cu 0.1000 0.0000
    Al 0.0220 0.0000
    N 0.0070 0.0000

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  1. Atlas of Continuous cooling transformation diagrams for Vanadium Steels, Vanitec, Kent, June 1985
  2. Atlas zur Warmebehaendlung der Staehle, Verlag Stahleisen mbH, Duesseldorf, Germany 1954.
  3. W.W. Cias, Phase transformation kinetics and hardenability of medium-carbon alloy steels, Climax Molybdenum Company, Greenwich 1973.
  4. G. Ghosh and B. Olsen, Acta Metall. Mater., 1994, 42, 3361-3370
  5. W.G. Vermeulen et al, Ironmaking and Steelmaking 1996, 23, (5), 433-437

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Further Comments


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materials, data, neural, network, martensite, start temperature, steel, composition, concentration, start, temperature

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