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Subroutine MAP_STEEL_NITSUB

  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

H.K.D.H. Bhadeshia,
Phase Transformations Group,
Department of Materials Science and Metallurgy,
University of Cambridge,
Cambridge, U.K.

Added to MAP: August 1999.

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Purpose

To calculate the nitrogen concentration in undiluted submerged arc welds.

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Specification

Language:FORTRAN
Product form:Source code

 SUBROUTINE MAP_STEEL_NITSUB(C,SI,MN,NI,MO,CR,V,AL,TI,CO,NB,TA,
&                            W,ZR,CU,NITPPM,CURR,NW,IFAIL)

 DOUBLE PRECISION C,SI,MN,NI,MO,CR,V,AL,TI,CO,NB,TA,W,ZR,CU
 DOUBLE PRECISION NITPPM,CURR,NW

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Description

MAP_STEEL_NITSUB calculates the nitrogen concentration in undiluted submerged arc welds for welding currents of between 450 and 650 Amps. It uses a fit to the results given in reference 1 to obtain an estimate for the nitrogen concentration, Nc, (ppm by weight):

Nc = {12.6141 - 0.0082 Iw} . Nw0.5 / F

where Iw is the welding current (Amps), Nw is the nitrogen content of the welding wire and F is the activity coefficient of the steel [2].

The activity coefficient is a factor which accounts for the influence of alloying elements on the solubility of nitrogen in dilute liquid steel. It is calculated from the concentrations (wt. %) of C, Si, Mn, Ni, Mo, Cr, V, Al, Ti, Co, Cu, Nb, Ta, W, and Zr present in the steel weld by calling MAP_STEEL_NITR. If any of the input values for the concentrations of C, Si, Mn, Ni, Mo, Cr, or V, are greater than certain specified limits, beyond which the nitrogen calculation is uncertain, then the value for the upper limit is used in the calculations. The input variables, however, remain unchanged on exit from the subroutine. It is assumed that Al, Ti, Co, Cu, Nb, Ta, W, and Zr are present as trace elements only.

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References

  1. H.K.D.H. Bhadeshia, L.-E. Svensson and B. Gretoft, 1988, Journal of Materials Science Letters, 7, 610-612.
  2. See MAP_STEEL_NITR.

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Parameters

Input parameters

C - real
C is the carbon concentration (weight percent). Upper limit for C is 0.2 wt%.

SI - real
SI is the silicon concentration (weight percent). Upper limit for Si is 0.8 wt%.

MN - real
MN is the manganese concentration (weight percent). Upper limit for Mn is 2.0 wt%.

NI - real
NI is the nickel concentration (weight percent). Upper limit for Ni is 3.0 wt%.

MO - real
MO is the molybdenum concentration (weight percent). Upper limit for Mo is 1.0 wt%.

CR - real
CR is the chromium concentration (weight percent). Upper limit for Cr is 1.0 wt%.

V - real
V is the vanadium concentration (weight percent). Upper limit for V is 0.5 wt%.

AL - real
AL is the dissolved aluminium (weight percent).

TI - real
TI is the dissolved titanium (weight percent).

CO - real
CO is the dissolved cobalt (weight percent).

NB - real
NB is the dissolved niobium (weight percent).

TA - real
TA is the dissolved tantalum (weight percent).

W - real
W is the dissolved tungsten (weight percent).

ZR - real
ZR is the dissolved zirconium (weight percent).

CU - real
CU is the dissolved copper (weight percent).

CURR - real
CURR is the welding current (Amps).

NW - real
NW is the nitrogen content of the welding wire (parts per million by weight).

Output parameters

NITPPM - real
NITPPM is the nitrogen content of the weld metal (parts per million by weight).

IFAIL - integer
IFAIL = 1 on exit if any of the concentrations of C, Si, Mn, Ni, Mo, Cr, or V exceed the specified limits. IFAIL = 0 otherwise.

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Error Indicators

IFAIL = 1 on exit if any of the concentrations of C, Si, Mn, Ni, Mo, Cr, or V exceed the specified limits. IFAIL = 0 otherwise.

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Accuracy

The typical error is ±13 ppmw.

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Further Comments

If the estimated value for the nitrogen concentration, obtained using the above equation, is less than zero, then it is set to zero.

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Example

1. Program text

      DOUBLE PRECISION AL,TI,CO,NB,TA,W,ZR,CU
      DOUBLE PRECISION C,SI,MN,NI,MO,CR,V,NW,CURR,NITPPM
      INTEGER IFAIL
C
      WRITE(*,*) 'Input C, Si, Mn, Ni, Mo, Cr, V (wt%):'
      READ (*,*) C, SI, MN, NI, MO, CR, V
      WRITE(*,*) 'Input Al, Ti, Co, Nb, Ta, W, Zr, Cu (wt%):'
      READ (*,*) AL, TI, CO, NB, TA, W, ZR, CU
      WRITE(*,*) 'Input nitrogen content of wire (ppmw):'
      READ (*,*) NW
      WRITE(*,*) 'Input welding current (Amps):'
      READ (*,*) CURR
      CALL MAP_STEEL_NITSUB(C,SI,MN,NI,MO,CR,V,AL,TI,CO,NB,TA,W,
     &                      ZR,CU,NITPPM,CURR,NW,IFAIL)
      WRITE (*,1) NITPPM
      IF (IFAIL.EQ.1) 
     &  WRITE(*,*) '**** WARNING **** Input data exceeded limits.'
      STOP
    1 FORMAT(//' Nitrogen content of weld = ',F7.2, ' ppmw')
      END

2. Program data

 Input C, Si, Mn, Ni, Mo, Cr, V (wt%):
    0.05 0.5 1.0 0.0 0.0 0.5 0.5
 Input Al, Ti, Co, Nb, Ta, W, Zr, Cu (wt%):
        0   0   0   0   0  0   0   0
 Input nitrogen content of wire (ppmw):
 50
 Input welding current (Amps):
 180

3. Program results

 Nitrogen content of weld =   89.70 ppmw

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Auxiliary Routines

MAP_STEEL_NITR

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Keywords

nitrogen, submerged arc, weld, activity coefficient

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Download

Download source code

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