BlockPacTM - moisture protection
for submerged arc welding fluxes
FOR READY TO USE FACTORY DRY WELDING FLUX
XA00167620
Factory dry agglomerated welding
flux for use without re-drying direct
from the bag
The moisture level of welding fluxes needs to be
controlled to prevent hydrogen induced cracking in thick
structural steels, all thickness high strength steels and
porosity in stainless or nickel based steels. This involves
climate controlled storage to prevent moisture reabsorption and/or re-drying of the flux to bring moisture
back to safe levels. These procedures and the
associated administration work are costly and time
consuming steps in welded fabrication which can be
completely avoided with ESAB’s moisture protection
BlockPac™ for agglomerated submerged arc welding
fluxes.
Submerged arc welding flux from moisture protected
25 kg BlockPac can be used direct from the package
without the need for re-drying. The laminated, multi-layer
aluminium foil has a welded seal and effectively protects
the flux against moisture re-absorption from the
atmosphere. The bags have unlimited shelf life and
require no special warehouse conditions, provided they
are handled with care and the foil is not damaged. Upon
opening, fresh and dry flux is guaranteed when the bag
is still in the block shape. This is the case either when
the bag and its contents are hard and non pliable or
when the bag is in block-shape with no air inside.
ESAB moisture protection BlockPac has been tested
extensively under adverse climatic conditions which, with
paper bags, would lead to moisture pick-up and re-drying
of the flux necessary. The diagrams on the next page
show the climate conditions and give evidence of the
100% protection provided by the BlockPac in terms of reabsorbed moisture and weld metal hydrogen content.
The diagrams on page 4 show that hydrogen levels of H5
or even H4 can easily be maintained on Column & Boom
applications while in tractor applications when only small
flux volumes are refilled, care should be taken and the
bags should be closed.
After use empty bags can be disposed environmentally
friendly. Recycling instructions according to EN13431 are
printed on the bag.
ESAB moisture protection BlockPac simplifies
consumables handling procedures and increases
customers productivity; in offshore and pressure vessel
fabrication, the petrochemical industry, nuclear, power
generation and other applications where the prevention of
cold cracking or porosity is crucial.
Benefits:
• No moisture absorption
• No re-drying prior to use
• Cost and time savings due to elimination
of the re-drying operation at customers
• Reduced risk of hydrogen induced cracking
• Storage under severe climate conditions
• Fully recyclable packaging
• Ready to use
A full 1200 x 1000 mm palette contains
1000 kg of moisture protected flux
Full protection from moisture
absorption
Climate Test Data
°C
60
% RH
60
100
55
Climate Test Data
°C
% RH
100
55
90
50
90
50
80
45
40
40
70
35
80
45
70
35
60
30
60
30
50
25
20
20
40
0
1
2
3
4
5
6
7
8
40
56 57 58 59 60 61 62 63 64 65 66 67 68 69 69 70
Weeks
Temp °C
% RH
50
25
Temp °C
% RH
Days
The moisture protection of BlockPac was tested in a climate chamber for 10 weeks at 45°C / 90% relative humidity,
corresponding to severe tropical conditions. In weeks 9 and 10 the dew point was artificially reached once a day and droplets
appeared on the outer packaging.
The moisture variations measured are within the accuracy of the test method itself which proves that no moisture absorption
takes place. Measurements of the all weld metal confirm low hydrogen levels of H4 after this severe treatment
(OK Flux 10.62/OK Autrod 12.32; hydrogen testing according to EN ISO 3690).
0,015
Hydrogen of all weld metal after climate chamber
according to EN ISO 3690
Diffusible hydrogen [ml/100g]
Moisture pick-up, 0-1000°C [%]
Moisture of flux after climate chamber
Moisture pick-up
0,010
0,005
0,000
-0,005
Accuracy of test method
-0,010
-0,015
0
1
2
3
4
5
6
Weeks
7
8
9
10
4,4
4,2
4,0
3,8
3,6
3,4
3,2
3,0
after 8 weeks
* Wrinkles and bends in foil
after 10 weeks
after 10 weeks *
Handling at customers
0,8
Tractor application; 3 kg filled into flux hopper
Weld metal hydrogen increase [ml/100g]
25°C, 60% RH
27°C, 80% RH
45°C, 90% RH
0,6
0,4
0,2
0,0
6,0
25°C, 60% RH
27°C, 80% RH
5,0
45°C, 90% RH
4,0
3,0
2,0
1,0
0,0
0
2
4
6
Open bag exposure time [h]
8
0
20
30
40
60
90
120
Open bag exposure time [min]
After opening, bags were exposed to 3 different climate conditions in order to investigate hydrogen pick up at the customers
site. Applications in which a complete bag is filled into a flux pressure tank as with a Column & Boom installation are looked at
separately from those where only 3 kg flux is filled into the hopper of a welding tractor.
In all cases it is beneficial to open BlockPac just before filling the flux into the hopper. When BlockPac is only partial emptied it
shall be reclosed and other adequate care shall be taken for temporary storage.
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international network of independent distributors brings the
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they are located.
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XA00167620 / 2014-11-17 / ESAB reserves the right to alter specifications without prior notice
Weld metal hydrogen increase [ml/100g]
CaB application; full bag filled into flux hopper