W
W
10 min.
25 min.
a
1
25 min.
65 min.
10 min.
1
10 min.
1
10 min. I
Inter Pass <95OC
>25mm
STEP 1
SET UP THE WELD PAD
Begin byinplacing
two copper bars parallel to each other
Dimensions in
millimetres
Dimensions
millimetres
on the base plate. This setup will form the foundation for
a
I 10 min.
10the
min.weld pad. Carefully deposit single weld bead layers
between the copper bars, ensuring the height reaches a
minimum of 13 mm. Plate thickness plays a crucial role
in maintaining the weld pad’s integrity during the welding
process, so adhere to specified requirements.
ASTM A240 or A160
>64mm
STEP 3
DETERMINE WELDING PARAMETERS
Before proceeding with the welding process, identify the
appropriate welding current based on the electrode’s
size. Ensure a short arc length for precise weld seams
and uniform distribution of the weld metal. Ray diffraction
techniques, coupled with optical microscopy, aid in
evaluating the weld structure and ferrite content.
65 min.
Dimensions in millimetres
STEP 2
STEP 4
Approximate Dimensions
Electrode
diameter
mm
Welding
currenta
A
width (w)
mm
length (l)
mm
1.6
2
2.5
3.2
4
5
6.3
35 to 45
45 to 55
65 to 75
90 to 100
120 to 140
165 to 185
240 to 250
12.5
12.5
12.5
12.5
12.5
15
18
30
30
40
40
40
40
40
a Or 90% of the recommended maximum value
esab.com
ASTM A240 or A160
COPPER BAR
The size of the base metal shall follow the following
dimensions (according to the size of the electrode):
>13mm
COPPER BAR
This comprehensive guide provides a step-by-step approach to prepare
a pad for measuring delta ferrite content in duplex stainless steel. From
setting up the weld pad and selecting the right material to determining
welding parameters and employing optical microscopy, each step is
crucial for accurate ferrite number measurement. By following this guide,
welders can achieve high-quality welds with optimal ferrite content,
enhancing the overall performance and longevity of the duplex stainlesssteel components.
Short Arc Length
COPPER BAR
MEASURING FERRITE
CONTENT IN DUPLEX
STAINLESS STEEL:
STEP-BY-STEP GUIDE
SELECT THE RIGHT MATERIAL
The choice of base plate material is vital for accurate
ferrite content measurement. Opt for Type 301, 302, or
304 austenitic stainless steel, which complies with ASTM
Specification A167 or A240. Alternatively, carbon steel
may be used, but ensure the weld pad is built up to a
minimum height of 18 mm to avoid adversely affecting the
results.
IMPLEMENT WELDING PROCEDURE
To maintain homogeneity, alternate the welding direction
with each pass. Position the weld stops and starts at
the ends of the weld build-up to create consistent weld
seams. Proper welding parameters and technique are
crucial to achieving a high-quality weld with the desired
ferrite content.
MEASURING FERRITE
CONTENT IN DUPLEX
STAINLESS STEEL:
STEP-BY-STEP GUIDE
This comprehensive guide provides a step-by-step approach to prepare
a pad for measuring delta ferrite content in duplex stainless steel. From
setting up the weld pad and selecting the right material to determining
welding parameters and employing optical microscopy, each step is
crucial for accurate ferrite number measurement. By following this guide,
welders can achieve high-quality welds with optimal ferrite content,
enhancing the overall performance and longevity of the duplex stainlesssteel components.
The size of the base metal shall follow the following
dimensions (according to the size of the electrode):
W
W
10 min.
25 min.
a
1
25 min.
65 min.
10 min.
1
10 min.
1
10 min. I
CONTROL INTERPASS COOLING
Proper interpass cooling prevents stress corrosion
cracking and maintains the weld’s mechanical properties.
Clean each pass before depositing the next weld bead,
and limit the maximum interpass temperature to 95°C.
Cooling the weld pad between passes can be achieved
through quenching in water no sooner than 20s, ensuring
no adverse effects on the ferrite number measurement.
Each pass of the last layer shall be air cooled to a
temperature below 425°C before water quenching.
STEP 6
SURFACE PREPARATION FOR ACCURATE FERRITE
MEASUREMENT
Dimensions in
millimetresin millimetres
Dimensions
When the anticipated ferrite content is 30 FN or less,
a
I 10 min.
10 utilize
min. a 360 mm mill bastard file to draw file the surface.
Achieving a smooth finish with no traces of weld ripple is
vital for accurate optical microscopy and ferrite number
readings. This step ensures precise ferrite content
measurement.
65 min.
Dimensions in millimetres
Approximate Dimensions
Electrode
diameter
mm
Welding
currenta
A
width (w)
mm
length (l)
mm
1.6
2
2.5
3.2
4
5
6.3
35 to 45
45 to 55
65 to 75
90 to 100
120 to 140
165 to 185
240 to 250
12.5
12.5
12.5
12.5
12.5
15
18
30
30
40
40
40
40
40
a Or 90% of the recommended maximum value
esab.com
STEP 5
By following this step-by-step guide and incorporating
plate thickness considerations, ray diffraction techniques,
optical microscopy, and ferrite number measurement,
welders can ensure high-quality welds with desirable ferrite
content in duplex stainless steel. Properly prepared weld
pads prevent stress corrosion cracking, contributing to the
longevity and performance of welded components.
STEP 7
EMPLOYING OPTICAL MICROSCOPY
Using optical microscopy, examine the prepared surface
to evaluate the weld’s microstructure and ferrite content.
This analysis is essential for confirming the weld’s integrity
and high-quality ferrite distribution.
STEP 8
MEASURE FERRITE NUMBER
Determine the ferrite number using appropriate
methods such as ASTM E562. Accurate ferrite number
measurement aids in assessing corrosion resistance and
mechanical properties of the duplex stainless steel weld
metal.