Handling of Welding Consumables

7/28/2019 Handling of Welding Consumables

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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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Handling of Welding Consumables