Basics of Welding PP

8/10/2019 Basics of Welding PP

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Types Of Welding

Welding

Gas Welding Arc Welding


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Normal practiced process

Manual Metal Arc Welding MMAWGas Tungsten Arc Welding GTAW

Flux Cored Arc Welding FCAW

Sub Merged Arc Welding SAW


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WELDING PROCESS

The present process of welding used tomanufacture various components generally are as

follows

MMAW- Manual Metal Arc Welding Process GMAW- Gas Metal Arc Welding process

GTAW - Gas Tungsten Arc Welding

FCAW- Flux Cored Arc Welding

SAW- Submerged Arc Welding


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SMAW/MMAW


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GTAW


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GMAW(MIG/MAG)


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FCAW


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SAW


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Advanced process

Narrow Gap Welding Laser Beam Welding

Electron Beam Welding

Plasma Welding

Plasma Transfer Arc Technique (PTA)

Robotic Welding

Orbital Welding


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Selection of Welding process

Type of Base Material The Joint Design

The lace of weldin

Welding Position

Type of consumables availability

The skill availability of personnel

The types of equipment availability


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&

WELDING EQUIPMENTS.


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RECOMMEDATIONS

The selection of the correct welding consumablesdepends on the following parameters

Base materials composition

e we a y o e s ee Selection of the welding consumables as per

ASME section-II- C

Acceptance of AWS or any other standardsdepends on the clients requirements.


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WELDING CONSUMABLES

The Welding consumables like the welding electrodes andfiller wires that are required and are recommended are asfollows

E-6013 Welding Electrodes for Welding in MMAWprocess for Carbon steel, Mild steel, For the generalpurpose welding applications up to thickness 18 mm or3/4th inch.

For thickness over the above mentioned must be weldedwith Low Hydrogen electrodes as per AWS E 7018 orE7018-1 Type of welding consumables.


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Welding consumables for various

steels.

General Mild steel Up to 18mmAWS 6013 class welding electrodes,

ER 70 S-6 in case of GMAW process.

General Mild steel Above 18mm

AWS 7018class ER 70 S2 & ER 70 S-6


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Selection contd.

For Radiography jointsThe following grades consumables are

.

AWS E6013 & E7018 classified Electrodes

ER 70 S2 TIG welding filler wires

ER 70 S-6 MIG Welding continuous filler

wires.


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Consumables- gases

ER 70 S-6 Solid wire for welding theGMAW (MAG) welding process

- -

carbon steel welding .

The use of 100 % CO2 gas for MAG

welding and 100 % pure Argon gas for TIGwelding applications are the main criteria.


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Alloy steels

AWS class of low alloy electrodes & wires


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Consumables- LAS

In the case of use of Low alloy steels where

, ,

creep properties are important and hence the

matching composition of the weld metals

are mandatory


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Consumables S.S.

Welding of Stainless steels like commonlyused steels such as 304, 304L, 308L, 309,

316. and other cate ories such as 310 321

347, Duplex, Super Duplex Steels, therespective grade of Electrodes and the Filler

wires to be used with proper shielding

gases.


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Stainless steel

301,304,308 ClassAWS E 308 & 308 L grades Electrodes

.

316 and 316 L

-AWS E- 316 & 316 L

-ER 316 L TIG and MIG fillers


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SS Contd.

For 309 Grade steelsAWS E 309 Electrodes

Dissimilar metals of SS and SS-MS

AWS 309L and 309 MoL

ER 309L & ER 309 MoL


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SS Contd.

Stabilized steels of 321, 347Namely Niobium/Columbium, Ti and Ta stabilizedsteels the use of

- e ectro es an w res oER 347 grade is recommended.

For other grades like 310,312, 317 the respectivegrades of consumables be used.


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Other metals

Cast Iron

-

Aluminium, Copper, Nickel, Magnesium

etc.


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Welding Position


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Proper Arc Length

Long arc results in:

Large globules melting

Wavering arc

Wide spatter and irregular bead

Short arc results in: Electrode sticks Poor penetration

Convex bead

Slag inclusions Irregular bead

Use short length for vertical welds


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Speed of Travel

Travel speed influences: Bead width

Penetration

Use a uniform speed

Both hands on the electrode holder

Operator comfort

Bead should be about twice the diameter of theelectrode wire


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Read the Bead


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TYPES OF EQUIPMENTS

Standard Type of welding Equipments Arc Welding Transformers

D.C. Rectifiers

Thyristor controlled Welding Rectifiers

Welding Invertors

TIG Welding Equipments

MIG/MAG Welding machines

Sub Merged Arc Welding machines


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MMA Power sources

Transformer RectifierWelding generator


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category of MIG Welding

Pulsed MIG Welding Machines, Inverter based MIG Welding Machines

Surface Tension Transfer Machines (STT)


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Cont

Under TIG Welding category we can have DC Pulsed welding machines

AC Square wave pulsing machines


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Advanced Welding Machines:

Electron Beam Welding machines

Laser cutting and welding

Plasma Welding


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Selection of the correct equipment

Selection of the right type of equipment isimportant to get the desired welding properties.

The selection decides the feasibility of the use of

the process. The selection should be based on the availability

of the equipment,

The acceptance of the process The convenience of the operation.


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Welding Defects


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TYPE OF DEFECTS

Lack of fusion Lack of Penetration

Crack

Porosity

Slag inclusion


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Lack of Penetration


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Lac of Fusion


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Undercut


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Porosity


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Crack


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ITS CAUSES AND REMIDIES

Re-drying of Consumables/ Proper Storage Base metal Cleaning.

Welding Parameter.

Use of correct welding consumables.


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Basics of Welding PP

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