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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/Welding8/3/2019 Fabrication Assign Weld Test
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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/