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Recommendat ions for thestorage, redry ing and hand ling ofESAB consum ables
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Fig. 1.
Recommendations for covered electrodes
The s torag e of co vered elec trod es
ca n b e a fairly d ifficult s ubjec t a s
a ir a lw a ys co ntains mo is ture a nd
elec trod e c oa tings a re prone tomo is ture pick-up. Too muc h
moisture in the co a ting c a n pro-
duce poros ity in the w eld or els e
the hydrogen coming from the
moisture c a uses cracks.
An ea sy w a y to a void a ll these
prob lems is to us e the new
Va cP a c. As long a s the vac uum ispres ent, the elec trod es a re d ry.
There a re no res tric tions rela ting to
storage climate.
After the fina l drying a t the fa c tory,
the electrodes are normally packed
in shrink-film pa pe r boxes . Thes e
boxes a re no t 100% a irtig ht, w hich
explains how moisture in thes urrounding a tmos phere c a n enter
them and b e a bs orbed by the
coa ting. The s pee d o f the mois ture
pick-up de pends on s evera l
fac tors a nd, w ithout tes ting the
mois ture conte nt, it is d ifficult to
judg e w hether or not the e lec -
trode s in a pa ckag e have toomuch moisture in their coating.
If the pa ckag es a re kept in the
storage conditions described
be low, they c a n be kept for a
ma ximum of one yea r for normal
use. Ca re must also be ta ken
during tra nsp ortation a nd ha ndling
to prevent moisture being re-absorbed.
If there is a ny do ubt a bo ut whether
a n elec trod e is dry enoug h, it
s hould be red ried a t the tempera-
ture a nd time indica ted on the
la bel on the pa ckag e.
How ever, pa cking elec trod es in
Va cP a c mea ns that there a re nores tric tions w hen it co mes to
storag e, other than that the pa ck-
a ge must be kept a t a tempera ture
that does not exceed 50C .
LMA Low Moisture Absorption
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For Va cP a c us ers , rea d the Va cP a c
s ec tion b elow.
ESAB introd uced the LMA conc ept
for ba s ic elec trod es to red uce
s ens itivity to the re-a bs orption o fmoisture. Electrodes with LMA
ha ve a low er initia l mois ture
content a nd the speed of
remo is tening is much low er than
that o f norma l ba s ic e lec trod es .
The usa b le time before red rying is
therefore inc rea s ed . This is s how n
in a climate of 32C , 75% rela tive
humidity in Figure 1.
StorageC overed elec trod es of a ny type w ill
pick up mo is ture only very s low ly if
they a re s tored under the follow ing
c lima tic cond itions :
At tempe ra tures
5-15C ma x. rela tive humidity60%
15-25C ma x. rela tive humid ity
50%
a bove 25C ma x. rela tive humidity
40%
During the w inter, it is po ss ib le to
ma inta in low rela tive humidity b y
keeping the temperature in the
s tore-room a t lea s t 10C a bove theoutdoor temperature. During
certain period s in the summer and
in a trop ica l c lima te, suffic iently
low relative humidity can be
ma inta ined by a ir dehumidific a tion.
If the elec trod es have be en s tored
in a co ld pla ce , a llow them to
reach the ambient temperaturebe fore breaking the pa ckag e.
RedryingLow -hydrog en ba sic elec trod es
s hould b e red ried before use
w henever there a re a pplic a tion
req uireme nts rela ting to w eld meta l
hydrog en c ontent a nd/or ra d io-
g ra phic s oundnes s (not needed for
Va cP a c ).
Ac id rutile s ta inles s elec trod es a nd
a ll types of ba s ic elec trod e ma y
prod uce pores in the w eld if they
ha ve no t b een s tored in s ufficiently
dry c ond itions . Red rying the
elec trod es w ill res tore the ir usa b il-ity.
Mild s tee l rutile a nd a c id elec-
trod es normally need no red rying.
Cellulose electrodes must not be
redried.
Elec trod es w hich a re s erious ly
da ma ge d b y mois ture ca n normallynot be red ried w ith firs t-c la s s
res ults . Thes e elec trod es s hould
be scra pped.
Holding ovenThe ho ld ing oven is used for
intermed ia te s tora g e to a void
moisture pick-up in the coating of
low -hydrog en elec trod es a nd a cidrutile s ta inles s electrod es . The
elec trod es w hich s hould be s tored
in the holding oven are:
1.Elec trod es that ha ve bee n
redried
2.Elec trod es that ha ve bee n
removed from their hermetica lly-
sea led conta iner
3.Elec trod es that a re reg a rde d a s
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80oC 150oC 200oC 250oC 300oC 350oC
43.32 50.10 39.95 33.30 53.16 38.48 67.6246.00 94.25 63.35 33.65 61.10 38.65 67.7046.16 94.55 67.15 63.53 61.41 38.85 68.1246.64 67.75 63.80 61.81 38.95 68.1792.18 68.15 67.13 63.10 48.00 73.0892.78 83.28 67.45 63.20 48.04 73.68
83.65 68.60 63.32 48.08 73.7884.58 68.81 63.41 48.15 73.79
85.65 69.21 63.53 48.30 74.4686.08 84.42 63.71 48.68 74.7892.26 84.52 68.82 53.00 74.7992.45 86.20 69.33 53.18 75.6592.58 93.13 83.50 53.35 75.75
92.15 84.60 53.68 75.7884.78 55.00 76.1892.86 61.30 76.28
61.50 76.3563.30 76.9663.34 76.9864.30 78.1667.50 83.2967.52 86.2867.60 92.35
Table 1. Recommended redrying temperatures, holding time two hours for
OK electrodes
be ing in go od co ndition a nd a re
trans ferred d irec tly from the
storeroom after unpacking.
Holding oven temperature: 120-
150C .
Precautions on siteKeep the electrodes in electrically-
hea ted q uivers a t a minimum
temperature o f 70C .
After w ork, return the rema ining
electrodes to the holding oven.
Redrying conditionsRed rying temperatures a nd hold-
ing times a re s pec ified on the
pa ckag e la bel.
The red rying tempera ture is the
tempera ture in the b ulk of the
electrodes.
The redrying time is mea sured from
the point at which the redryingtempera ture ha s been rea ched.
Do not s ta ck more than four la yers
of e lec trod es in the red rying oven.
It is rec ommend ed not to redry
co vered elec trod es more tha n
three times .
A s ummary of rec ommend ed
red rying cond itions for ES AB
elec trodes is g iven in Ta ble 1.
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ESAB equipment for the dry storage and redrying ofelectrodes
PK 1 dry-storage containerThe P K 1 is a lig ht a nd ha ndy dry-
storage container for electrodes. It
is ea sy to c a rry a round . The
s tora ge temperature is a round
100C .
PK 5 drying equipmentThe P K 5 is a comb ined drying a nd
dry-storag e s ystem for most types
of e lec trod e. The drying time a t full
effec t is one to s even hours de -
pending on the type of elec trod e.
The tempera ture is thermos ta tica lly
controlled a nd rang es from 50-
300C . The electrod es should be
s tored in the P K 5 without pac ka g -
ing.
SK 40 dry-storage cabinet
The S K 40 is a dry-s torag e c a binet
w ith four remo va ble she lves fors toring elec trod es . The elec trod es
s hould be s tored w ithout pac king.
The c a b inet is eq uipped w ith a
thermometer, thermostat and
control lamp.
PK 410 drying cabinetThe P K 410 is a rob ust c a binet for
the drying a nd d ry sto ra g e ofelec trod es . The drying te mpe ra ture
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ca n be regula ted b etween 0C a nd
450C . The dry-s torag e tempera-
ture is a round 150C. The P K 410
is eq uippe d w ith a c ontrol la mp,
elec tronic thermometer a nd
electronic thermostat.
The P K 410 also has a s even-da y
timer. This timer ma kes it pos s ib le
to c ha nge a utoma tica lly from
drying to dry storag e for selec ted
times a nd temperature ra nges .
Discoloration in the coatingIf the colour of the electrodes
cha nges during s tora ge, theyshould b e sc ra pped or an
ESAB represe nta tive should
be c ontacted.
Damaged coatingMechanically damaged elec-
trod es on w hich pa rts of the
coa ting a re miss ing w ill not
perform c orrec tly a nd shouldbe scrapped.
VacPacElec trod es in Va cP a c w ill not
pick up a ny mo is ture d uring
s tora ge. They req uire no red rying
be fore us e, provide d that the
pa cka ge is unda ma g ed . This is
indica ted by a vac uum in the
package.
Handling VacPac electrodesP rotect Vac P ac from da mage at
a ll times .
The outer bo a rd pa cka g ing offers
extra protection from mechanicalda ma ge to the me ta l foil. Hand le
the single inner metal foil with
special care.
Do not us e a knife or any other
s harp objec t to open the outer
boa rd pac ka ging.
Fig ure 2 show s ho w much ea s ier it
is to hand le Va cP a c e lec trod esco mpa red w ith ordina ry pa cked
electrodes.
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Fig 2. Comparison of procedures for guaranteeing dry electrodes in a workshop
between normal packaging and VacPac .
Normal packing VacPac
Before using VacPac elec-trodesCheck that the protective foil still
co ntains a vac uum. If the va cuum
has be en los t, red ry the elec trod es
be fore us e. B efore o pening the
pa ckag e, ma ke s ure that it has the
sa me tempera ture a s the a mbienta ir.
C ut open the protec tive foil a t one
end. Leave the foil on the pa ckag e.
Do not ta ke o ut more tha n one
elec trod e a t a time, thereb y ens ur-
ing tha t the rema ining elec trod es
are still protected inside the
pa cka ge . P ut the lid b a ck on thepla s tic b ox.
Discard or redry electrodes that
have been exposed to the a tmos-
phere in an opened Va cP a c for
more tha n 12 hours .
Recommendations for OK FluxES AB fluxes fo r S AW ha ve exc el-
lent storag e properties a nd a s -delivered OK Fluxes ha ve a mois-
ture content with a nominal level of
no mo re tha n 0.05% determined a t
1,000C.
It is of g rea t impo rta nce for the
q uality of the w eld meta l that the
mois ture c ontent is kept a s low a s
pos s ib le. OK Fluxes a re d elivered
in a moisture-resistant paper bagw ith a pla s tic lining ba g , 25 kg
B ucket, 250 kg B ig B a rrel a nd 500-
max. three times
Remaining
electrodes
Stores
< 60% RH
Rebaking
350oC, 2h
Holding o ven 150oC ,
< 24h
Quiver
80oC, < 8h
Welding
Stores
Welding
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Suitable flux quantities depend on
the d es ig n a nd ventila tion o f the
oven, b ut the heig ht of the flux
la yer should not exce ed 50 mm.
Reb a ked flux sho uld b e s tored a t
150 25C until use.
Fluxsilo JS 200 is a n elec trica llyhea ted oven for keeping flux dry. It
has a ca pa city of 200 litres a nd the
temperature c a n be reg ula ted
between 0-300C thermostati-
cally controlled.
Redrying tempera ture : 300C for
tw o to four hours
S to ra g e vo lume : 200 l
Flux hopper size: 500 x 500 x
1,700 mm
1,000 kg B igB a g . How ever, it is
pos s ib le for OK Fluxes to p ick up
mois ture during ina ppropria te
ha ndling , stora g e or tra ns port. This
is genera lly indica ted by porous
s la g a nd/or pores on the w eld.
ESAB ha s draw n up guide lines for
ha ndling to a void this .
1 OK Flux must b e s tored dry to
prevent remois tening. As a rule,
the c lima te c ond itions in the
s tore s hould not excee d 60%
rela tive humidity a t a tempera-
ture of 20C 10C .
2 Flux ba gs should not be ex-
pos ed to d irec t moisture s uch a s
ra in or snow.
If the a bo ve c onditions a re me t,
OK Flux has the follow ing s torag e
times:
Buckets andB igB a rrels ma x. 3 yea rs
P a per ba g s ma x. 2 yea rs
B igB a g ma x. 6 months
During long prod uction s toppa g es ,
flux in op en flux co nta iners on the
w eld ing ma chine or at the w eld ing
s ite s hould b e ta ken ba ck to the
s toreroo m or kept in a n oven a t
150C 25C .
If for any rea son OK Flux ha s been
remo is tened , it c a n normally b e
res tored by redrying it in a drying
oven. The follow ing va lues for
temperature a nd time a pply.
Fus ed OK Flux: 200
50CB onded OK Flux: 300
25C
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Base Metal:P os ition b a s e meta l vertica lly a nd
s pa ce a pa rt to provide for a ir
c ircula tion a nd minimise cond en-
ses conta ct points.
S tore inside, prefera b ly in a hea ted
room w ith as cons tant a tempera -
ture a s pos s ib le. Humidity c ontrol
is a ls o d es ira ble, if it ca n be
achieved.
Electrode:S tore in a hea ted roo m w ith
uniform temperature control and, if
pos s ible, w ith humidity c ontrol a s
well.
Hold w eld meta l in the w eld ing
a rea for 24 hours before unpa cking
to a llow its te mpera ture to e q ua lise
w ith tha t of the s urrounding a rea .
S tore unpa cked ma teria l in a
heated c a binet.
Recommendations for aluminium wires
Us e d ust c overs on a ll w elding
equipment.
Atmospheric conditions affectweld quality
Many fabricators experience
w eld ing prob lems a t d ifferent times
of the year. Moisture (H2O) is a
prime s ource of hyd rog en. At a rc
tempera tures, wa ter brea ks dow n
relea s ing hydrog en ato ms tha t
ca use p oros ity in we ldme nts.Shielding gas supplies are
controlled to very low moisture
content (-57C dew point or low er).
Likew is e, the a tmos pheric
conditions in a fabricating facility
need to b e c ontrolled to prevent
moisture condensation from
forming on elec trod e o r ba s e
metal.Aluminium, which is allowed to
repea tedly co me into co ntac t with
Fluxtork J K 50 is a n elec tric a llyheated ca binet and s tora ge silo
tha t c a n dry 50 kg of flux for ab out
three hours. The te mpe ra ture the n
drops to 150C w ithin 12 hours .
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water, will eventually form a
hyd ra ted oxide (AlOH) coa ting .
Moisture from condensation
pres ent on e ither the elec trod e o r
the ba se metal ca n cause two
prob lems during w eld ing :
P oros ity ca used b y hydrog en
g enera ted from the brea kdo w n of
w a ter or from the b rea kdo w n of
hyd ra ted oxide (AlOH) present on
the metal surfaces.
Entrapment of the actual oxide(AlOH) present on the metal
s urfac es , in the w eldment.
Terms :
Relative Humidity - The ra tio o fthe q uantity of wa ter vapo ur
pres ent in the a tmos phere to the
q uantity which w ould s a tura te the
a ir a t the e xis ting tempe ra ture.Rela tive humidity is e xpres s ed a s a
percenta ge number and need s to
Relative Relative
(Tair - Tmetal) Humidity (Tair - Tmetal) Humidity
C % C %
0 100 12 44
1 93 13 41
2 87 14 38
3 81 15 36
4 75 16 34
5* 70* 18 30
6 66 20 26
7 61 22 23
8 57 24 21
9 53 26 1810 50 28 16
11 48 30 14
Dew point conditions versus relative humidity:
be mo nitored in the we ld ing a rea .
Dip ta nks , clea ning s ta tions , etc ,
affect relative humidity.
Dew Point - The tempera ture a twhich c ondensa tion of wa ter
vapour in the a ir ta kes pla ce .
Mois ture w ill co nde nse on meta l
s urface s w hen their temperature is
eq ual to or below the dew point.
For ea ch relative humidity
perce ntag e, there is a
co rres ponding de w point.
Air Temperature - The tempera-ture o f the a ir in the w eld ing a rea
a t a ny g iven time.
Metal or Electrode Temperature- The te mpe ra ture o f the elec trod e
or ba se meta l a t a ny given time.
(Ta ir - Tmeta l) - Temperature o f
the a ir minus the temperature o fthe meta l sho w n in C.
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The a bo ve cha rt s how s the rela tive
humidity a t w hich detrimenta l
w a ter cond ens e w ill form for a
numb er of g iven d ifferentia l tempe-
ratures.
* Exa mple - If the rela tive humidity
in the we ld a rea is 70%, the ba se
meta l a nd elec trod e must b e no
co lde r than 5C b elow the air
temperature to prevent mois ture
condensation.
Conclusion:
In an aluminium welding shop, theuniformity o f a ir and meta l tempe -
ra tures is impo rta nt es pec ia lly
w hen the rela tive humidity is high.
Elec trod e a nd b a s e meta l s hould
be a llow ed to s ta bilise to the w eld
a rea temperature. The e lec trod e
s hould not b e o pened in the w eld
area for 24 hours after entry from a
co oler s tora ge a rea . The ba se
metal should be clea ned a nd
brus hed w ith a clea n sta inles s
steel brush prior to welding. ESAB
recommends mild alkaline
s olutions a nd c omme rcia l de greas -
ers tha t do not evolve toxic fumes
during w eld ing . Welders should
w ipe joint ed ge s w ith a clea n cloth
d ipped in a vola tile p etroleumba s ed s olvent. All surfac es must
be thoroughly d ried a fter clea ning .
Recommendations for cored and solid wires
When it c ome s to w ires , the o bjec t
is once a ga in to a void c ontac t with
w a ter or moisture. It is mos t
importa nt to a void direc t c onta ct
w ith w a ter.This could ta ke the fo rm
of ra in or the c onde nsa tion of
moisture o n a cold w ire.To a void cond ens a tion, keep the
w ire in the o rig ina l pa cka g ing a nd,
if nece s s a ry, lea ve the w ire to
wa rm up to a t lea st the a mbient
temperature b efore o pening the
package.
Other hydrogen-containing sub-
s ta nces . like o il, g rea s e a nd
corros ion. or subs tances tha t
co uld a bs orb moisture must a ls o
be a voide d o n the s urfac e of the
wires.
If the wire is kept in its originalunopened pa ckag ing in a clima te
of 10-30C , < 65% RH, its s helf life
is reg a rded a s virtually unlimited .
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ESAB ABB ox 8002, S E-402 77 G tebo rg, S w ed enP hone: + 46 31 50 90 00, Fa x: + 46 31 50 91 70E-ma il: co nsumab les@esa b.s eInternet: ww w.esa b.c om
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