fabrication assign weld test

8/3/2019 Fabrication Assign Weld Test

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Materials fabrication

Welding Test

Prepared by: Walid Sayed Abd Allah

SMANF

07p4016

Submitted to: Dr. Adel El Shabasy

11/21/2011

Faculty of EngineeringCredit Hours Programs


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Weld verification

In manufacturing, welds are commonly used to join two or more metal surfaces. Because these

connections may encounter loads and fatigue during product lifetime, there is a chance that

they may fail if not created to proper specification. For example, the base metal must reach acertain temperature during the welding process, must cool at a specific rate, and must be

welded with compatible materials or the joint may not be strong enough to hold the surfaces

together, or cracks may form in the weld causing it to fail. The typical welding defects, lack of

fusion of the weld to the base metal, cracks or porosity inside the weld, and variations in weld

density, could cause a structure to break or a pipeline to rupture.

Why weld testing?

Defects occur during welding which affect the quality and hardness of the plate

Other defects occur through lack of knowledge of and skill of the welder For the training of welders

Weld testing types

weld testing

destructivetesting Non-destructivetesting
http://en.wikipedia.org/wiki/Weldinghttp://en.wikipedia.org/wiki/Fatigue_(material)http://en.wikipedia.org/wiki/Specificationhttp://en.wikipedia.org/wiki/Specificationhttp://en.wikipedia.org/wiki/Fatigue_(material)http://en.wikipedia.org/wiki/Welding


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Destructive testingDestructive testing can be divided into two parts:

Tests capable of being performed in the workshop

o Tensile

o Bendingo Impact

o Hardness

o Fatigue

o cracking

Laboratory tests

o Macroscopic

o Microscopic

o Chemical

o corrosive

Tensile testingMaterial is sectioned and edges rounded to prevent cracking.

Punch marks are made to see elongation.


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Bend testing1. Shows Physical condition of the weld

2. Determine welds efficiency

a. Tensile strength

b. Ductility

c. Fusion and penetration

Procedures:

Bend through 180O

the specimen should be a minimum of 30mm wide

The fulcrums diameter is 3x thickness of the plate

The bottom rollers have a distance of the diameter of the former + 2.2 times the

thickness of the plate

Upper and lower surfaces ground or filed flat and edges rounded off.

the tests should be one against the root -another against the face ,and in some cases a

side bend

Root bend


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Face bend

Impact testing

There are two types:

1. CHARPY

2. IZOD

Impact testing gives the toughness and shock loading of the material and weld at varying

temperatures with a notch such as under cut

The measurement is the energy required to to break a specimen with a given notch

2mm depth at a 45o

bevel or a U notch


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Charpy

Izod


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Hardness testingThis gives the metals ability to show resistance to indentation which show its resistance to wear

and abrasion

The tests are

Brinell

Rockwell

Vickers diamond pyramid

Scleroscope

Vickers Hardness


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Fatigue testing

Testing of Material that is subject to fluctuating loads

HIGH Electromagnetic tester

WOHLER Uses rotating chuck with weight

Cracking testing

REEVES Test study the hardening and cracking of welds.

The compatibility of electrodes for the metal being joined.

Three Sides Are Welded With Known Compatible Electrodes

The front edge is welded with the test electrode

if incompatible it will crack


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Microscopic

Used to determine the actual structure of the weld and parent metal

Up to 50,000 times magnification with an electron beam microscope

Polishing must be of a very high standard

Macroscopic

Examined using a magnifying glass.

Magnification from 2 to 20 times.

It will show up slag entrapment or cracks.

Polishing not as high as micro

Etching Reagents

These are acids used to show up different structures in metals For steels the most common is 1-2 % nitric acid in distilled water or alcohol.

Aluminum uses a solution of 10-20%caustic soda in water


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Non-destructive testing

DYE PENETRANTSThese are an aid to visual inspection

Will only find surface defects

Types

Red

Flouresant

CAUTION

Oil based

Water washable

Visual

while welding

The rate the

electrode melts

The way the weld

metal flows

Sound of the arc

The light given of

after welding

Under cut

Lack of root fusion

Any pin holes

from gas or slag

Amount of spatter

Dimensions of

weld


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MAGNETIC PARTICLEMainly for surface defects

Some sub surface defects can be found

Only ferrous metal

ACOUSTICS

Striking with a rounded object

Ringing tone if no defect

Tone changes when object is cracked

APPLICATION OF A LOADUsed to test pressure vessels

Pipe lines

The item for testing is filled with water or oil it is then pressurised using

a pump

A safety valve is set 1.5 to 2 times below the working pressure


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PRESSURE TEST

RADIOGRAPHICX-RAY

GAMMA RAY

Electromagnetic radiation of short duration

Both of these methods are a danger to health


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ULTRASONIC TESTINGThis uses high pitched sound

The sound will not pass through an air gap so bounces back and is picked up on a receiver

The reader is a oscilloscope


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Referenceswww.wikipedia.com

www.engfunda.com
http://www.wikipedia.com/http://www.wikipedia.com/http://www.engfunda.com/http://www.engfunda.com/http://www.engfunda.com/http://www.wikipedia.com/

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