2012

alhuzaim_af

[Type the company name]

8/2/2012

Welding 2 go

2

“One must try by doing the thing; for though you

think you know it, you have no certainty until you try.”-

Sophocles

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I would like to express my gratitude to all those

who gave me the possibility to complete this

handbook.

I want to thank the Royal

Commission for Jubail for giving me

the opportunity to continue my

education and be able to prepare

such a handbook.

Special thanks are reserved for

Jubail Technical Institute for

support and providing the facility

and workshops

Many thanks are represented to Hobart

institute of welding Technology for

providing great training and materials

Also I would to thank My Photographer Mr.

Mohanad Mohammed Alnajdi for his great

photos

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What is welding?

Welding is the joining of metals or other materials

at their molecular level. There are four components

to a weld. The four components are the metals

“weldment”, a heat source, filler material, and

shield from the air whether its gas or flux.

Welding Concept

The welding process works as following. The

weldment gets heated to its melting point, with

shielding from the air to protecting the weldment

from oxidizing, and then a filler metal is added to

the area that needs to be joined eventually

producing a single piece of metal.

History of Welding

A process known as forge welding was used when

the Industrial Revolution began around 1750 AD.

It’s a very simple process that takes two or more

pieces of metal and heated. When the metal is hot

enough you simply hammer the joint areas together

until they fuse. This all worked well enough until

1886.

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Introduction

It is very important to know the difference between a

“joint” and a “weld” and use terms properly

Standard terms must be used when dealing with

weld joint and weld geometry to avoid errors in

communication

5 Basic Joint Types

Butt Joint

Corner Joint

T-Joint

Lap Joint

Edge Joint

Butt Joint

A Joint between two members aligned in the same plane

Bevel-groove

Flare-bevel-groove

Flare-V-groove

J-groove

Square-groove

U-groove

V-groove

Edge-flange

Braze

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Corner Joint

A joint between two members located approximately at

right angle to each other

Fillet

Bevel-groove

Flare-bevel-groove

Flare-V-groove

J-groove

Square-groove

U-groove

V-groove

T-Joint

A Joint between two members located approximately at

right angles to each other in the form of a T

Corner-Flange

Edge-flange

Plug

Slot

Spot

Seam

Projection

Fillet

Bevel-groove

Flare-bevel-groove

J-groove

Square-groove

Plug

Slot

Spot

Seam

Projection

Braze

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Lap-Joint

A Joint between two overlapping members in parallel

planes

Fillet

Bevel-groove

Flare-bevel-groove

J-groove

Plug

Edge Joint

A joint between the edges of two or more parallel or

nearly parallel members

Slot

Spot

Seam

Projection

Braze

Bevel-groove

Flare-bevel-groove

Flare-V-groove

J-groove

Square-groove

U-Groove

V-groove

Edge

Corner-flange

Edge-flange

Seam

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Groove-Weld Type

Square-Groove

Single-V-Groove

Double-V-Groove

Single-Bevel-Groove Weld

Single-U-Groove Weld

Welding type that the

edge of the weldment is

square with or without

root opening

The edge of the

weldment is beveled

to a cretin degree

usually 37

Used with thicker

material to

maintain

penetration and

prevent distortion

Used to provide

accessibility and

help in penetration

This design reduce

the stress in the joint

therefore less

cracking

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Fillet- weld Type

Surfacing Weld

Seam Welds and Spot Welds

A weld usually

accurse in T-joints or

Lap joints

Used in corroded

material to rebuilt

and increase

thickness

This is resister weld

where the electrode

apply pressure and heat

to form the weld usually

used in sheet metals and

automobiles

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Welding Sequence

Z-weave a technique used to

move the electrode in Z

motion to fill up the joint

Stringer bead multiple

beads beside each other

to fill up the joint this

technique reduce the

heat input in the joint

Boxing technique used

in welding pressure

vessels prevent leaking

from corners

Chine intermittent

fillet weld used to

save consumables

and reduce the

heat input in the

weldments

Staggered

interment fillet

weld used to

prevent distortion

in weldments

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Parts of a Weld

Back-step Sequence

used to reduce the

heat input in the

weldments

Weld Face: is the contour of the weld this could be

convex, concave and flat

Face Reinforcement: is the distance from the

parents’ metal to the weld face

Root reinforcement: is the distance from the parents’

metal to the weld root

Weld Toes: is the side lines where the weld ends and

the Heat Affected Zone starts

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Root Surface: is the contour of the root

Weld Root: the filler metal penetrating between

parent metals

Back Weld: is a weld made from the root side of the

joint after the main weld is done

Backing Weld: is a weld made from the root side of the

joint before the main weld is done

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Joint spacer: used to fill the root opening between

parent metal

Fusion Face: is the beveled face where the fusion

takes place

HAZ: is the area next to the weld that been affected

by the heat and change the structural property

Weld Interface: is the deepest penetration the

filler metal reach in the base metal

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Weld Size: is the size of the weld from the surface of

the base metal to the deepest point in the root

Incomplete point penetration: means the joint is

not fully penetrated by the molten fillet metal

This is a combination of square groove and fillet weld

its clearly shows that this joint is not a complete joint

penetration

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Incomplete fusion is not limited to the root can

accrue in the hot, fill and even cover pass

Incomplete fusions can accrue due to the lack of

accessibility and cleaning

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Welding Positions

Correct fusion must be throw out the legs of a fillet

weld

1F Position: it’s a fillet

weld where the weld is flat

the travel angle is 10°-15 and the work angle is 90°

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2F Position: it’s a

fillet weld where the

weld is horizontal, the

travel angle is 10°-15 and the work angle is

45°

3F Position: it’s a

fillet weld where the

weld is vertical, the

travel angle is 45°and

the work angle is 10°-

15 push angle

4F Position: it’s a fillet

weld where the weld is

overhead and horizontal,

the travel angle is 10°-

15 and the work angle

is 45°

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1G Position: it’s a

groove weld where

the weld is flat the

work angle is 90°

and the travel

angle is 10°-15

2G Position: it’s a

groove weld where

the weld is

horizontal the work

angle is 90° and the

travel angle is 10°-

15

3G Position: it’s a

groove weld where

the weld is vertical

the work angle is

90° and the travel

angle is 10°-15

4G Position: it’s a

groove weld where

the weld is

overhead the work

angle is 90° and

the travel angle is

10°-15

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1G Position: the pipe

is turning while the

welding the axle of the

pipe is horizontal

2G position: the pipe

is fixed, the axle of the

pipe is vertical and the

weld is horizontal

5G Position: the pipe

is fixed, the axle of the

pipe is horizontal and

the weld is vertical

6G Position: the pipe is

fixed; the axle of the pipe

is 45°

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Welding Symbols

All welding symbols have an arrow and a

reference line.

P: Pitch (center-to-center spacing) of welds

L: Length of weld

F: Finish symbol

A: Groove angle; included Angle of countersink

For plug welds

R: Root opening; depth of filling or plug and slot

welds

S: Depth of preparation; size or strength for

certain welds

T: Specification, process or other reference

E: Groove weld size

The line between F and A is Contour symbol

(Tail omitted when reference is not used)

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Fillet Welding Symbols

Fillet weld symbols it looks just like the cross

sectional area of the weld. The symbol in the top of it

is the contour which is in this case is convex. It can

be concave or flat/flush

1/8 4 - 8

LS1

LS2

In the top fillet weld symbols 1/8”

is the leg size “LS” in this case

the leg LS1 and LS2 are equal if

they are not equal it should be

written as the following

1/8 X 3/16

Then show at the drawing which

LS should be 1/8 and which

should be 3/16. Shown one of

them is enough to know the

other.

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When the weld symbol is placed below the reference

line, it shows that a weld is on the arrow side of the

joint.

When the weld symbol is above the reference line, it

indicated that a weld is on the other side of the joint

When the weld symbol is both above and below the

reference line, it indicates that welds is in both sides

The Leg size of fillet weld is always on the left side of

the symbols

The length of a fillet weld is always in the right side

of the symbols

Example:

In this a

Double fillet weld

Size of weld “LS” 5/8”

Length of weld “segments is 5”

Length of pitch is 10”

Flat contour

Finished by machining

Methods of welding mechanized

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Fillet Weld Calculations

To find the weight of an equal leg fillet weld we need

to find the Cross Section Area “CSA”, the length of the

weld and the density of the metal. If we take the

drawing 1 as an example and we suppose it’s a mild

steel, flat face, the following steps is how to calculate the

weight of the weld

To find out the CSA for any triangle we have to

know the length of the base and the height of the

triangle and divided by two. The mathematical formula

for the triangle CSA is.

Fillet weld CSA = .5 X Base X Height

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After calculating the CSA, we can calculate the

volume of the weld by multiplying the CSA by the

length of the weld.

Finally, to find the weight of the weld we should

multiply the volume by the density that will give us the

weight of the weld.

Example 1:

Calculate the weight of the above fillet weld

we will use the below welding symbol to help us find

what essential information to calculate the weight like

the leg size and the length of the weld, if we assume the

material is a mild steel for example A36. As it shown in

the symbol the leg size is 5/16 inch and it mention only

one size that’s mean the leg size is equal. Also the

length of weld is 12 inch. The density of all steel is 0.283

lbs/in³. So now we can start following the steps above.

Fillet weld Volume = CSA X Length of weld

Fillet weld weight = Volume X density of metal

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Step 1

Fillet weld CSA = .5 X Base X Height Fillet

weld CSA = .5 X .3125 X .3125 = .049 in²

Step 2

Fillet weld Volume = CSA X Length of weld Fillet

weld Volume = 0.49 X 12 = .59 in³

Step 3

Fillet weld weight = Volume X density of steel Fillet

weld weight = .59 X .283 = .17 lb

The weight of the fillet weld

is 0.17 lb

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Example 2

If we take example 1 and we add reinforcement as

showing in the drawing. Then we need to calculate the

reinforcement separately and then add the flat fillet to

the reinforcement to get the total weld weight.

To calculate the reinforcement we need to calculate

the Face Dimension ”FD” first, we can apply Pythagoras'

Theorem law to get the FD and then we can calculate

the reinforcement CSA.

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As we calculated in the first example the weight of

the flat fillet weld is 0.17lb. So we will pursue to

calculate the reinforcement and add the total weight for

the weld.

Face Dimension FD= √( ) ( )

FD=√( ) ( ) = .44 in

CSA Convexity = .5 X FD X reinforcement

CSA Convexity = .44 X .125 X .5 = .03 in²

Volume of convexity = CSA X Length

Volume of convexity = .03 X 12 = .36 in³

Weight of convexity = Volume X Density

Weight of convexity = .36 X .283 = .1 lb

Pythagoras'

Theorem

Total weight of the weld =

Weight of fillet weld + weight of reinforcement

Total weight of the weld = 0.17 + 0.1 = 0.27lbs

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Groove weld:

Square-groove welds are the most

economical to use, but are limited

by thickness of the members.

Welds for one side are normally

limited to a 1/4 inch or less

With thicker materials joint

accessibility must be provided for

welding to ensure weld soundness

and strength

Bevel- and J- groove welds are

more difficult to weld than V- or

U- groove welds. Bevel welds are

easier in horizontal

Welds in using J- and U-grooves

can be used to minimize weld

metal. These welds are very useful

in thicker sections

J-groove are more difficult to

weld because of the one vertical

side (except in horizontal)

J-and U- are used when

economic factors outweigh the

cost of edge preparation

Flare -bevel and flare-v-groove

welds are used in connection

with flanged or rounded member

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Groove Weld Calculations

Example:

To calculate the weld weight in a single bevel pipe

we can divide the weld into three areas as showing in

the third drawing. The root opening and the thickness of

the material will be area 1, the bevels will be area 2,

and the reinforcement will be area 3. First we calculate

the Cross Sectional Area for all three areas.

-CSA1 is basically rectangle where the area is the

width by the height

CSA1 = root opening X thickness

CSA1 = .125” X .625 = .08 in²

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-CSA2 is two triangles where the area is (.5 X the

height X base). We can calculate the height by

subtracting the thickness from the root face. To

calculate the base which is the side opposite in the

triangle we can use TAN the height or the side adjacent.

CSA2 = thickness - root face X {(thickness – root

face) X tan (

)} X .5 X 2

CSA2 = .625 - .125 X {(.625 - .125) X tan 30} X .5 X 2

= .15 in²

-CSA3 to calculate the reinforcement area we have

to calculate the face dimension first and that by

calculating the side opposite and multiply it by 2 and

add the root opening to it.

Face Dimension = (side opposite X number of bevel)

+ root opening

Face Dimension = (.5 X tan 30 X 2) + .125 =.685 in

CSA3 = Face Dimension X Reinforcement X .5

CSA3 = .685 X .125 X .5 = .04 in²

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We add the CSAs to get the total area of the weld

∑ CSA = CSA1 +CSA2 + CSA3 = .08 + .15 + .04 = .27 in²

Finally to calculate the weight we need to calculate

the length of the weld. Since it’s a pipe we need to

calculate the circumstance which (𝝅 X Diameter) then

we multiplying it by the density of the steel which is

.283 lbs/in³.

Weight of the weld = CSA X (𝝅 X Diameter) X density

Weight of the weld = .27 X (.3142 X 6”) X .283 = 1.4 lbs

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Example:

Calculate the weight of the weld in double v groove

basically solve for single V and then divided by two.

Given:

V groove weld both side plate thickness = .625”

Total root face = .125”, root opening = .067”

Included angle = 75 degree, convex reinforcement = .067”

Consumable density= .1 lbs/in³, weld length=14”

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Solution

Total CSA of the weld

CSA1 = Root Opening X thickness = .067 X .625 = .042

in

FD= Tan (37.5) X (T/2 – Root Face/2) = .767 X ( .3125 -

.0625)= .192

CSA2 =.5 X .192 X .25 = 025 in² X 4 = .096 in²

CSA3 = .5 X Face Dimension X Reinforcement

CSA3 = .5 X ( .192 + .067 + .192 ) X .067 = .015 in² X(2) =

.03 in²

Total volume of the weld

V= CSA X Length = .168 X 14 = 2.35 in³

Total weld weight = Volume X Density

Total weld weight =2.35 X.1 = .235 lbs