WELDING JOINT DESING AND WELDINGSYMBOLS

Welding Joint Design andWelding Symbols

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RAJA KMECHANICAL ENGINEER(TEKLA STRUCTURES)MOB :- +971 0558384955.

After completing this chapter, you will be able to:◦ Sketch the five basic welding joints◦ Explain the factors that must be considered when

choosing a weld joint design◦ Discuss the factors to consider when selecting a weld

joint design◦ List and explain the information that can be included on a

welding symbol◦ Sketch a welding symbol and identify the components

Refers to the way pieces of metal are put together or aligned with each other

◦ The five (5) basic weld joint designs are:

Butt Joint

Lap Joint

Corner Joint

Tee Joint

Edge Joint

Name five basic weld joints that may be found in a weldment.

Two ways of fitting up an outside corner joint.

Open Corner Closed Corner

NOTE: "fillet weld" = a triangular shaped weld in a corner

Name three types of joints that use fillet welds?

Accessibility for welding Strength requirements Cyclic or static loading Material thickness Welding process to be used Material type Code Requirements Cost

Side Note: some considerations in selecting a type of joint to use on a fabrication.

Bevel Groove Vee Groove

J Groove

U GrooveSquare Groove

Name two edge preparations used with butt joints.

Edge preparations used with butt joints.

More Important Groove Preparations:

Bevel Groove – single and double

Vee Groove – single and double

1

2

1 2 3

4

Single V Groove

Double V Groove

Cost◦ A number of items affect weld cost

Even a slight change in groove angle can save time and money.

Weld Size Weld Faults

NOTE:While Leg Size is the usual method to specify and measure weld size, the Effective Throat is a more accurate measure of fillet weld strength!

EffectiveThroat

Actual ThroatLeg Size2

Leg Size1

TheoreticalThroat

Convexity

¼

How is the size of a fillet determined and what is used to measure it?

1. After selecting specified size gauge from set, measure Leg1

2. Measure Leg2

3. Verify throat with other side of gauge (face of gauge should touch weld)

L1

L2

3/8

How To Use A Fillet Gauge

Undercut – most predominant weld fault

◦ Fix: Short arc length, proper amperage and speed

Describe four typical faults in single-pass horizontal fillet welds.

Other typical faults in single-pass horizontal fillet welds:

Porosity:

Lack of shielding gasWet electrodeGreasy material

Other typical faults in single-pass horizontal fillet welds:

Slag Inclusion: Improper cleaning / removal of slag

Porosity

Undercut

Poor Fitup

Lack of Penetration

F = FilletG = Groove1 = Flat2 = Horizontal3 = Vertical4 = Overhead

G = Groove1 = Horizontal Rolled2 = Vertical5 = Horizontal Fixed6 = 45 Incline

Welding Symbols

Welding Symbols (cont’d.)

3 parts of the welding symbol body:

Arrow

Reference LineTail

Welding symbols ◦ Applied to reference

line at the base Reference lines have

an arrow side (near side) and other side (far side)

No size specified

What if the symbol were on this side?

Sketch the weld required by this symbol.

As you see in this example, the weld symbol usually looks like the weld cross

section shape!

Symbol must be above the reference line

indicating make weld on "Other Side" of joint from where arrow is pointing.

Complete the welding symbol that specifies the weld shown.

1/4

1/4 3/8

1/4

(1/4 x 3/8)

Nothing in the symbol specifies unequal leg size location.

If there are not obvious reasons to put larger leg on one side of joint (e.g. thicker metal), then it must be specified on drawing.

Complete the welding symbol that specifies the weld shown including dimension specifications.

1/4

1/4

3/8

3/8

1/4

3/8


3/16

3/16

3/16 3 - 9

3/16

3 9

3/16

Sketch the weld required by this symbol including dimensions.

1/2

1/2 2 - 8

2 - 8

1/2

1/2

1/2

2 8


1/4

3/8

1 3

1 3

1/4 1 - 3

3/8 1 - 3


1/4

1/2

1/2

2 3 1/2

1/2 x 1/4 2 – 3 ½

1/2 x 1/4 2 – 3 ½


GTAW1/8

Process:Contour:

Finishing Method:

1/8

"TIG"FlatWelding

NOTE: The “Weld All Around” symbol is not required for pipe weld connections but may be included for clarity

In other cases, it is needed to specify that requirement

Sketch the weld required by this symbol including dimensions and notes.

GTAW1/8

Process:Contour:

Finishing Method:

1/8

"TIG"FlatWelding

NOTE: The “Flag” symbol.

Indicates field weld or on-site welding


NOTE: The broken arrow line should be used to point at the side to be prepared.

NOTE: The vertical line must always be on the left side.

Complete the welding symbol that specifies the weld shown.

40

3/8

3/840°


Process:Contour:

Finishing Method:

1/4FCAW

1/4 G

Flux CoredArc Welding

Convex

Grinding


3/16

3/16

NOTE: Efforts should be made to avoid Hi/Lows for a smooth surface

SURFACING FUNCTIONS: Buildup Stainless Overlay Abrasion Resistant Overlay


2

1/81/8 2


1 1/4 1/8 45

3/8 (1/2)

3/8

1/2SMAW

FCAW

SMAW3/8

1/8

45°13/8

1/2

2 3


THE ENDTHANK YOU

WORK DONE BY

RAJA KMECHANICAL ENGINEER(TEKLA STRUCTURES)MOB :- +971 0558384955.

WELDING JOINT DESING AND WELDINGSYMBOLS

Engineering

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