SHIELDED METAL ARC WELDING (SMAW)

1.Applications of SMAW the
 process are fluctuated and wide spread. De-
forthcoming upon the covered cathodes accessible it tracks down broad use in all major
creation businesses which might incorporate things of various fixes to shipbuilding and tension vessel manufacture.
Average terminals utilized for significant creation with their particular uses are
depicted momentarily.
1.1Electrodes for Welding Low Carbon Steels
These are very much evolved anodes and are advertised under various brand names. A large portion of these have a place with cellulosic, rutile, and essential covered
types regardless of iron powder. Weighty covered assortment can be utilized as contact
cathode which is magnificent for welding in vertical-up position.
1.1.1. Cellulose Coated Electrodes (IS : E100413; AWS E6010)
These are typically light covered, all position cathodes with a powerful
infiltrating bend and slight weak slag; appropriate for all position work. The weld metal saved is exceptionally bendable.
 appplications: Pipelines, tanks, pressure vessels, structurals, and field work where profound infiltration is important. exceptionally appropriate for pressure pipelines which can't be welded from inside.
1.1.2 Rutile Coated Electrodes
There are three principle classifications of rutile covered cathodes.
Classification 1(IS : E206411; AWS E6012)
it is an all position cathode, with great entrance and fast freezing
slag. It is not difficult to work in all positions including vertical-down
Applications: Storage tanks, gear spaces, hardware, steel furniture,
truck bodies, foundry hardware, shaft develop, and so on
Classification 2 (IS : E307411; AWS 6013)
An all position cathode which gives solid and smooth curve with medium infiltration. It gives low scatter and simple to eliminate slag. The anode is appropriate for crossing over holes in joints. It gives high affidavit rate.
Applications : Structures, building development, tanks, pipelines, apparatus parts, auto bodies, steel window outlines, ranch hardware, and so forth
Class 3(IS : E307412; AWS E6013)
An all position cathode for primary work. Medium entrance, least
scatter. Slag is not difficult to separate. Smooth dab and simple to work in all positions
counting vertical-down.
Applications : Building development, vessels, tanks and boilers, pipe-
lines, spans, rail route carts, ships, trailors.
Pressure pipelines which can't be welded from inside, oil capacity
tanks, railroad mentor boards.
Train fire-boxes, bike outlines.
1.1.3/Rutile Plus Iron Powder Coated Electrodes
There are three principle classes of these coatings.
Classification 1 (IS : E307512; AWS E7014)
A medium weighty covered all position cathode containing iron powder
that empowers the utilization of weighty current which subsequently prompts higher
welding yield with a statement productivity of upto every available ounce of effort. The weld metal is
exceptionally flexible.
Applications: Used for welding pressure pipelines, oil capacity tanks,
ships, boilers, rail route carts, and so forth at high welding speeds. Likewise appropriate
for fixing steel castings.
Classification 2 (IS: 327512 K; AWS E7024)
It is a weighty covered cathode with high statement rate for downhand
butt and filet welds as well as flat filet welds. The anode is very
simple to control and delivers smooth welds with extremely low scatter misfortune.
High welding current can be utilized to increment welding result and usefulness.
Testimony proficiency is almost 140%. It tends to be utilized as a "contact anode".

Applications: bridge priles., aeribly of carth' moving enuipment, neary maniten)e

etc.

Category 3 (IS : E347512L; AWS E7024)

=* Si her heavy copied non powder laitre de djoWhhanatal recovery in

horizontal fillet welds. It can also be used as a 'touch electrode

" plications : Useful for high spect, "wowing, ef weave straunds lie

crane and bridge girders, assembly of earth moving equipment, and paili

heavy machinery, etc.

7.9.1.4. Acid Coatings (IS : E422413; A WS E6020)

A medium heavy coated electrode producing, a luid shag for downhim.

horizontal, and vertical welding. It is specially suited to welding or low calt)

steel where high strength and high quality weld deposits are required; partia.

larly suited to applications where resistance to high stress and fatigue is inp

Lant. Use of high current and high welding speeds are recommended ior ex.

nomical welding with these electrodes.

Applications : Used for welding heavy structural work, bridges, crana,

locomotive fire boxes, truck chasis and frames. Excellent for continuous

downhand, horizontal fillet welds and for vertical-up welding.

7.9.1.5. Basic Coatings (IS : E616514 HJ; AWS E7018)

A medium-heavy coated 'low-hydrogen' iron powder type electrode

giving an extremely smooth arc, medium penetration and least spalter. Slag is

easily removable. Easy to operate in all positions. The weld metal is highly

ductile and crack resistant. Specially recommended for heavy joints under I-

straint and subject to dynamic loading. Deposition efficiency about 115%. I

needs to be kept dry; bake before use at recommended temperature.

Applications :

Used for welding blast furnace steel work, atomic

reactor shell and pipework, heavy welded fabrications as replacements for

castings, bridges, penstocks, root runs in heavy and restrained joints, Also

used for welding steels designed for service at sub-zero temperatures down 0

-33°C.

79.1.6 Special Coatings (IS : E922xxxP; A WS E6027)

A super-heavy coated iron powder electrode for deep penetration bull

and fillet welds. Square butt welds in plates upto 14 mm thick can be made. Il

can, however, be used only in flat and horizontal welding positions.

Applications : Used for welding of heavy deck plates, structurals,el

by the deep penetration technique thus it avoids beveling and riling o

ÉtOOVe:dt can also be used for depositing sealing run on the backside with)

the precessity of chipping out the Too, and ror deposiling Fillet welds wit

penetration beyond the root as in plate girders for bridge work.

72.2. Electrodes for Welding Low Alloy and High Tensile Steels

ysome of the coaled electrodes used for welding MISLA (high sites"

low alloy) steels for specific applications are listed.

[7:56 pm, 19/03/2022] ⚙️BIPUL⚙️: 79,21. Cellulose Coatings (S : E10022A; AWS 7010 -A1)

It is a cellulosic type, light coated, all position electrode that gives a thin

friable slag and good ponetration. The weld metal deposited is 07 0-59%0 Mo

sieel that has good ductility and creep resistance.

Applications : Used for welding C-Mo piping, road building equipment,

boilers, pressure vessels, alloy steel chain links, truck frames and bodies, high

tensile sice! pipelines for oil and gas transmission. Also recommended in

welded fabrication to be used for service at elevated temperature upto 525°C

79.2.2. Rutile Coatings

Three categories of elcctrodes, depending upon the core wire composi-

tion, are included.

Category 1, 0-5% Mo-steel (IS : E31422 A; AWS E 7013-A1)

A heavy coated rutile type all position, low alloy, medium-high tensile

sieel electrode that gives 0-5% Mo-steel weld deposit. The electrode gives

quiet arc, low spatter, and easily detachable slag. In a butt joint of a pipe or a

tube, arc is very easy to strike or restrike and hence specially recommended for

pipe welding . The weld profile produced is smooth with regular ripples.

Applications : Recommended for welding medium-high tensile and low

alloy steel of 0-5% Mo, and 1% Cr-0-5% Mo compositions. Also recom-

mended for welding steels used in boilers, power plant, oil refineries and

chemical plants in the form of structurals and pipes for elevated temperature

service upto 525 °C.

Category 2, 1-2% Cr-0-5% Mo Steel (IS: E31432C; AWS E8013 B2)

A heavy-coated all position rutile type, low alloy medium-high tensile

strength electrode that gives 1-2% Cr-0-5% Mo steel deposit. The electrode

gives quiet arc, negligible spatter, and easily detachable slag. Easy arc initia-

tion in pipe Or tube butt joint; hence specially recommended for pipe welding.

Applications : Used for welding pipes and structures in boilers, power

plants, oil refineries, and chemical plants for clevated temperature service upto

550°C.

Category 3, 2-25% Cr - 1% Mo steel (IS : E31431-D; AWS E 9013 B3)

It has characteristics similar to those for category 2 except that the weld

deposit obtained is 2-25% Cr - 1% Mo steel.

Applications: Used for welding pipes and structurals in boilers, oil

refineries, and chemical plants for service at elevated temperatures upto

600°C.

7.9.2.3. Basic Coated Electrodes

Maximum number of electrodes used for welding HSLA steels are of

¡he basic coated type; characieristics of a few of these, which are used for

lypical applications, are described under six categories.

Category 1 (IS : E611514H; AWS E 7016)

A medium-heavy coated, all position, low-hydrogen electrode suitable

tor welding cast steel, difficult to weld steels high in carbon and sulphur, and