Saturday, May 29, 2010

2nd day at pangkor

Cam biase.....bangun pagi2 dipulau mesti cari makan dulu...coz nak g mandi laut nanti..so pagi2 dengan xmandi nyer trus g pekan Pangkor ntuk mencari makanan..huhu...dapat la makan nasi lemak..huhu..lepas makan nasi lemak trus je siap2 nak mandi air laut...objective arini nak pusing pulau naek moto,..hehe...tapi kene mandi first..then malam nak g pancing ikan kat jetty..hehe..pasal tu kene sewa moto..hooho..so ktorg mandi start kol 9am...heheh..coz air sejuk lage mase tuh...lagepon orang xramai ..semua masih tido lage kot..so lepas je mandi...rehat2 jap...then siap2 mencari moto ntuk disewa..hehe...


then sampai je tempat ktorg sewa moto...jumpa la apek cina tua nie ngan anak buah nyer 'mappler'..coz aku yang nak sewa moto so kene la nego ngan diorg ...'apek, nie moto brape satu'...apek tuh xjawab terus...anak buah dier cakap...RM 30 sehari...hahaha...murah gak coz mase kat jetty mase baru2 sampai ade apek cina offer aku rm50 sehari...demmit apek tuh mak up tnggi...hahaa..so aku tnye balik...nie kalu gua sewa dua moto xleh dapat rm50 ke...hehe...tetiba je owner apek cina tuh trus cakap...tapi pkai alat bantuan khas la yang letak kat leher tuh...then trus aku teringat series My name is Earl ..ade watak psal org tua pkai alat tuh..haha...xsangka ade gak kat Pulau Pangkor wat bisnes sewa moto..hehehehe...trus je aku amek dua moto..haha...lepas amek moto...trus g pusing pulau..haha..bes gak la...aku naik ngan sedara , abg aku naek ngan abg ipar....haha...syok gak naek moto kat pulau..hehe..coz dah lame xnaek moto..heheheheh...lepas je pusing pulau trus makan keow taw sup and ABC...combination panas dan sejuk...cam yin and yang..hahahaha....puas hati..trus balik hotel..tido...haha..sampai kol 4 ptg


Lepas je bangun tdo trus berendam balik..hehe..tapi malam nie plan nak g mancing still on la coz umpan semua da beli...hehe...lepas mandi laut mandi dalam pool lak..hahaha...mandi je keje nie...

So, bile da makan malam semua..trus je ready joran untuk g pancing ikan..so aku xde la tolong sngt coz da penat main air petang tuh.lepas siap2... g la start moto g jetty...seram gak jetty tuh..hehehe...coz tmpt dier sunyi and jelap..mula2 xjumpa jetty tuh coz gelap..then pusing balik tgk jmpa dua house guard kosong yang sunyi..hehe...kat situ la jetty..haha...ktog still xmatikan enjin moto coz gelap nak nak letak umpan..hehehe...then trus jela mancing..tetiba ade 3 moto sampai..ingt polis je ape..siap ngan lampu lage..haha..bile dekat ngan ktorg first dengar suara...brader...dapat banyak ikan ke...haha..ktorg balas la baru nak start..hehe..selepas sejam memancing ...aku masih xdapat pon ikan.hampeh btol...tapi umpan slalu abes,...kdng2 rasa la ikan tu cuit umpan...ade skali da dapat..tapi tali putus...hampeh tol...abang aku dapat 3 ekor anak ikan...hahaha...aku tgk brader laen ade la dapat anak ikan yu...berbaloi gak mancing..hehehe...tpi ktorg amature,..nak wat camne...lepas umpan abes ktorg blah dari tmpt tuh...balik2 je trus cuci tngan coz da busuk bau umpan ikan..hohoho..then trus tdo..keh,,,sampai sini je update,,,nnti balik aku update lage

Friday, May 28, 2010

1st day at pulau pangkor

Wassup ..hehe..nie baru lepas mandi laut...hehe..trus update blog..nasib baik la aku bwak laptop and maxis broadband..so leh la update skit2...bes gak mandi laut coz dah 6 bulan xmandi kan..hehe...ktorg bertolak dari rumah pukul 9pagi tadi..so pergerakan ktorg nie slow skit coz ikut jalan lama and banyak nak berenti..hehe...then bekfast nasi lemak kat hentian guthrie...lepas je berkfast trus ke manjung dulu coz nak solat jumaat dulu...lepas je solat jumaat trus g lumut waterfront and amik ferry dalam kol 3pm..tapi before naik ferry,,, g usha jap tali pancing n mata kail..mane tau nak memancing ke...hehe..abes gak la dekat rm10 beli benda2 camtu...sesudah sampai di hotel..trus makan n mandi...hehe...then tetiba abg ipar ajak lak main banana boat...gua layan jela..haha...dan2 trus diorg soh duk depan skali mase naik banana boat tuh..hahaha..layaaaannn je...hehehehehe...dah lame xnaik banana boat sejak 8 tahun lepas kot..hehe..perghhh...tpi first naek kat PD...kat PD bes giler coz 3 kali jatuh...mmg layan la...nie kat pangkor dapat jatuh skali je dlam laut..hehe..so malam nie plan nak mancing ikan...wish me luck dapat ikan..tuk kakak sedara aku kalu bace blog nie..haha..sory beb...ktorg have fun kat sini...mybe nex week g kuching lak kite enjoy kat sane...keh22...udah penat menaip nie..so gtg (got to go)..hoho..lapar

Thursday, May 27, 2010

Trip to Pulau Pangkor

Arini saya g pulau pangkor ngan family...hehe...so excited bangun awal pagi...hehehe..tpi dah banyak kali g pulau pangkor...haha...xpela...

Wednesday, May 19, 2010

Airasia oh Airasia

tajuk arinie lebih kepada percutian yang telah dirancang sebelum aku masuk kerja ngan petronas...time tuh kalu tak silap aku bulan 11, so ade promotion dari airasia free seat..so aku trus la cek kat ternet..then trus la book tiket g langkawi untuk bulan 5, atau lebih detail 14hb mei 2010..aku budget mase time tuh leh amek cuti jumaat..tapiiiii...baru ahad lepas baru aku sedar psal tiket tambang murah nie..haha...mybe coz harga dier rm6 je sehala so aku terus terlupa ..hahaha..rugi gak la..hmpehh betol..nie coz byk kerja smpi lupa nak g bercuti ke langkawi..hehe

Sunday, May 2, 2010

Material Corrosion Engineer - Liquid Penetrant Examination

Liquid Penetrant Examination

Methods & Techniques
-detecting discontinuities which open to surface of nonporous metal and other material
-typical discontinuities: cracks, seams, laps, cold shuts, laminations & porosity
-either colour contrast or fluorescent penetrant, shall be used with one of the following 3 penetrant process:
Water washable
Post-emulsifying
Solvent removable
-so, six liquid penetrant techniques available

1) Technique for Standard Temperature
1. Liquid penetrant is applied to the surface, allowed to enter discontinuities
2. All excess penetrant is removed and dried
3. Developer is applied:-to absorb any penetrant trapped in discontinuities
-contrasting background to enhance the visibility of
penetrant indications
4. Dyes in penetrants are either colour contrast or fluorescent

2) Technique for Nonstandard Temperature
The examination procedure requires qualification technique of the penetrant materials
1. Fabricating the comparator block
i. shall be made of aluminium, ASTM B 209, Type 2024, 3/8 in. (9.5 mm) thick, and face dimensions of 2 in. x 3 in. (50 mm x 75 mm)
ii.at center of each face, area of 1 in. (25 mm) diameter shall be marked with 950°F (510°C) temperature-indicating crayon or paint
iii. The marked area shall be heated with a blowtorch/Bunsen burner to a temperature between 950°F (510°C) and 975°F (524°C)
iii.the specimen is immediately quenched in cold water, which produces a network of fine cracks on each face
iv. block is dried by heating to 300°F (149°C) temperature
v. after cooling, block is cut in half. One-half shall be designated block “A”, another one block “B”
vi. for alternative solution, separate blocks 2 in. x 3 in. (50 mm x 75 mm) can be made using the heating and quenching as described above, where both block shall be designated “A” and “B”

2. Comparator Application
i.For temperature less than 40°F (5°C),
-to qualify the examination procedure for temperature less than 40°F (5°C), the proposed procedure shall be applied to block “B” after the block has been cooled and held at the proposed examination temperature
-a standard procedure shall be applied to block “A” in the 40°F to 125°F (5°C to 52°C) temperature range
-indication of cracks shall be compared between blocks “A” and “B”
-if indications obtained under block “B” are essentially same as block “A”, the proposed procedure shall be qualified for use

ii. For temperature greater than 125°F (52°C),
-the qualifying procedure is same as procedure for the temperature less than 40°F (5°C)
-for this qualification procedure, the upper and lower temperature limits shall be established
-example: to qualify a procedure for the temperature range 126°F (52°C) to 200°F (93°C), the capability of penetrant to reveal indications shall be demonstrated at both temperatures
iii. Alternate techniques for Colour Contrast Penetrants,
-permissible to use a single comparator block for standard and non-standard temperatures, and make comparison by photography
-firstly, process of non-standard temperature is being done. Photograph is taken.
-block shall be cleaned
-then, process of standard temperature is being done. Photograph is taken.
-comparison between both photographs

Calibration
-light meters shall be calibrated at least once a year or whenever the meter has been repaired
-if not been used for one year or more, should calibrated again


Applications
For temperature of the penetrant and surface of the part is between 40°F (5°C) and 125°F (52°C):
Standard Temperature Technique shall be used as specified

For temperature of the penetrant and surface of the part is below 40°F (5°C) or above 125°F (52°C):
Nonstandard Temperature Technique shall be used as specified


Supervision
1. WRITTEN PROCEDURE REQUIREMENTS
-based on requirements listed in Table T-621, ASME V 2007
-any change of requirements of essential variable in Table T-621, shall require requalification of the written procedure by demonstration.
-any change of requirements of nonessential variable does not require any requalification


2. CONTROL OF CONTAMINANTS
-certification of contaminant content shall be obtained for all liquid penetrant materials used on nickel base alloys, austenitic or duplex stainless steels and titanium
-the certification shall include the penetrant manufacturers’ batch numbers and the test results


3. SURFACE PREPARATION
-by grinding, machining
-the surface to be examined and adjacent areas within at least 1 in. (25 mm) shall be dry and free of all dirt, grease, lint, scale, welding flux etc.
-typical cleaning agents are detergents, organic solvers, descaling solutions etc.
-degreasing and ultrasonic cleaning methods
-cleaning solvents shall have certification of contaminant as described before

4. EQUIPMENT¬¬¬¬¬
Penetrant material
-descriptions of liquid penetrant classification and material types are provided in ASTM E 165-02: Standard Test Method for Liquid Penetrant Examination
-Fluorescent penetrant shall not follow a colour contrast penetrant examination.
-intermixing of penetrant materials from different families or manufacturers is not permitted
-retest with water washable penetrants may cause loss of marginal indications due to contamination

Application
-may be applied by dipping, brushing, or spraying
-if by spraying, use compressed-air type apparatus. Filter shall be placed on upstream side near the air inlet, to preclude any contamination

Penetration (Dwell) Time
-the minimum penetration shall be as required in Table T-672, ASME V 2007

Types of penetrants:
i. Water-Washable Penetrants
-excess penetrant shall be removed by water spray
-water pressure shall not exceed 50 psi (350 kPa)
-water temperature shall not exceed 110°F (43°C)
-after removed with water spray, surfaces shall be dried by blotting with clean materials or using circulating air, where the surface temperature should not raised above 125°F (52°C)

ii. Post-emulsification Penetrants
Lipophilic Emulsification
-excess penetrant shall be emulsified by immersing the part with emulsifier
-emulsification time is depending on the type of emulsifier and surface condition or maybe determined experimentally
-after emulsification, mixture shall be removed by rinsing with water. Manufacturer shall recommend the water temperature and pressure



Hydrophilic Emulsification
-the parts shall be prerinsed with water spray using the same process as for water-washable penetrants
-prerinsing time shall not exceed 1 minute
-after prerinsing, excess penetrant shall be emulsified by immersing/spraying with hydrophilic emulsifier
-manufacturer shall recommend the bath concentration
-after emulsification, mixture shall be removed by rinsing with water. Manufacturer shall recommend the water temperature and pressure



For both lipophilic & hydrophilic emulsification
-after rinsing with water, surfaces shall be dried by blotting with clean materials or using circulating air, where the surface temperature should not raised above 125°F (52°C)


iii. Solvent Removable Penetrants
-excess penetrant shall be removed by wiping with cloth/absorbent paper. Repeat until most traces shall be removed
-remaining traces is removed by lightly wiping the surface with cloth/absorbent paper moistened with solvent
-care should be taken to avoid the use of excess solvent
-flushing the surface with solvent, after application of penetrant and before developing is prohibited
-after wiping the surface, it shall be dried by normal evaporation, blotting, wiping or forced air.


Developer
-shall be applied as soon as possible after penetrant removal
-with colour contrast penetrants, only wet developer is used
-with fluorescent penetrants, a wet/dry developer is used

Dry Developer Application
-applied by soft brush, hand powder bulb, powder gun (dusted evenly on the examined surface)

Wet Developer Application
-before applying suspension type wet developer to the surface, developer must be agitated to ensure adequate dispersion

i. Aqueous Developer Application
-may be applied to either wet or dry surface
-shall be obtained by dipping, brushing or spraying. Provided a thin coating is obtained over entire surface
-drying time might be reduced using warm air, provided the surface temperature is not raised above 125°F (52°C)
-blotting not permitted

ii. Nonaqueous Developer Application
-applied only to a dry surface, by spraying or brushing
-drying shall be normal evaporation





Developing time
-shall be begins immediately after application of dry developer or when the wet developer coating is dry
-based on Table T-672, ASME V 2007

Interpretation

-final interpretation shall be made within 10 to 60 min after developing time
-if bleed-out does not alter the examination results, longer period are permitted
-examination shall be performed in increments if the surface is large enough
-if penetrant diffuses excessively into developer, observation of the formation of indications during application of developer may be closed

a) Colour Contrast Penetrants
-developer forms a uniform white coating
-surface discontinuities indicated by bleed-out of penetrant, normally deep red colour that stains the developer
-excessive cleaning indicated by pink colour
-inadequate cleaning may produce excessive background, making interpretation difficult
-minimum light intensity of 100 fc (1000 1x) is required during surface examination

b) Fluorescent Penetrants
-examination is performed using ultraviolet light (black light) in darkened area
-examiners shall be in darkened area for at least 5 min before performing examination, to enable their eye to adapt darkened area. Glasses or lens worn shall not be photosensitive
-black light shall achieve minimum of 1000 µW/cm2 on the surface part
-reflector and filters should be checked. Broken filters shall be replaced
-black light intensity shall be checked with light meter



c) Interpretation based on application

i. Welded Pipeline
-any indication with maximum dimension of 1/16 in. (2 mm) or less may be classified as nonrelevant
-any unknown indication status shall be regarded as relevant until re-examined to determine whether the imperfections really exist
-surface may be ground or conditioned before re-examination
-after indication is determined to be nonrelevant, it doesn’t need to be re-examined
-relevant indications are those caused by imperfections
-linear indication is where the length is more than three times the width
-rounded indication is where the length is three times the width or less

Acceptance Standards
-relevant indication shall be considered defects if any of the following conditions occur.

For linear indication:
1) evaluated as crater or star cracks and exceed 5/32 in. (4 mm) in length
2) evaluated as cracks other than star or crater cracks
3) evaluated as incomplete fusion and exceed 1 in. (25 mm) in total length in continuous 12 in. (300 mm) length of weld or 8% of length of weld length

For rounded indication (individual pore):
1) Size of individual pore exceeds 1/8 in. (3 mm)
2) Size of individual pore exceeds 25 % of thinner of nominal wall thicknesses joined
3) Distribution of scattered porosity exceeds the concentration permitted in Fig. 19 or Fig. 20, in API 1104.

For rounded indication (cluster pore):
1) Diameter of cluster exceeds ½ in. (13 mm)
2) Aggregate length of cluster in any continuous 12 in. (300 mm) of weld length exceeds ½ in. (13 mm)

Material Corrosion Engineering HIC Testing

INTRODUCTION

Hydrogen Induced Cracking (HIC) occurs when carbon steel is exposed to hydrogen sulfide (H2S). It’s a direct result of electrochemical corrosion reactions between the sour service and wet H2S environment. The risk of this should be considered when hydrogen sulfide partial pressure becomes greater than 3.5mbar in standard.

Carbon steel pressure vessels should not be affected by HIC damage where H2S levels are lower than 3.5mbar in a normal service life cycle. HIC is common in wet a H2S environment which is often known as sour service. The cracking over a prolonged period of time without inspection will reach a critical point and the steel component i.e. pressure vessel that could easily fail. Simply put hydrogen induced cracking damage increases as the level of hydrogen sulfide increases. Examples of hydrogen induced damage are:

1) Formation of internal cracks, blisters or voids in steels.
2) embrittlement (i.e. loss of ductility).
3) High temperature hydrogen attack (i.e. surface decarburation and chemical reaction with hydrogen).

Prevention or Remedial Action
1. internal cracking or blistering
o Use of steel with low levels of impurities (i.e. sulfur and phosphorus).
o Modifying environment to reduce hydrogen charging.
o Use of surface coatings and effective inhibitors.

2. hydrogen embrittlement
o Use of lower strength (hardness) or high resistance alloys.
o Selection of materials of construction and plating systems.
o Heat treatment to remove absorbed hydrogen.

3. high temperature hydrogen attack
o Selection of material (for steels, use of low and high alloy Cr-Mo steels; selected Cu alloys; non-ferrous alloys).
o Limit temperature and partial pressure H2.

2.0 OBJECTIVE
This testing is establish to evaluate the resistance of pipeline and the pressure vessel plate steels to HIC caused by hydrogen absorption from aqueous sulfide corrosion.
As a corrosion engineer, need to observe and witness all the steps and the equipments to perform the testing are complied as per written in the approved procedure.



3.0 PROCEDURE
Materials and Testing Apparatus
1) Reagent – Solution A which is N2 gas for purging, H2S gas, NaCl, CH3COOH and distilled or demonized water.

2) Testing apparatus – As shown in figure 3.1 & 3.2


3) Specimen – a) Size - Cut into 100mm long by 20mm wide.
b) Thickness - 1) Max at 30mm, for greater than 30mm, a max of 1mm
shall be removed from each of surface.
2) For small diameter, thin wall ERW and seamless, the
thickness must be 80% of full wall thickness of that
pipe.
c) Number – Three (3) specimens from each pipe.
d) Location – 1) For welded, taken from the weld, 90 deg from the weld, 180 deg from the weld.
2) For seamless, taken 120 deg apart around the circ.
e) Orientation – 1) Seamless: Parallel to longitudinal axis of the pipe.
2) Welded: Parent metal of longitudinally welded pipe.
3) Spiral welded: Parallel to the weld for the parent metal
4) Welded: Perpendicular to the weld for weld area.
5) ERW pipe: Parallel to the weld of the weld area.
4) Sample preparation – test specimen shall be ground either wet or dry and finished with 320 grit paper.
5) Sample Cleaning – test specimen shall be degreased with degreasing solution and rinsed with acetone.



Procedures
1. Test specimen is set in the test vessel with the wide faces vertically in place.
2. All the specimens are separated by glass or non metallic rods with min 6mm.
3. The ratio test solution: total surface = 3 ml: 1 cm2
4. Solution A shall be prepared in a separate sealed vessel and purged with N2 for at least 1 hour at rate of 100 ml per min per liter. The pH for the solution shall be at 2.7.
5. The N2 purge and the H2S gas shall be introduced near the bottom of the test vessel.
6. Purging of N2 if needed for at least 1 hour with rate 100 ml per min per liter, after that H2S gas shall be bubble through the test solution 200 ml per min per liter for the first 60mins. Thereafter, a positive pressure of H2S shall be maintained.
7. The concentration of H2S in the solution should be at 2,300ppm which measure by titration.
8. pH at start for solution A after H2S saturation shall not exceed 3.3. If Solution B, pH shall be in the range of 4.8 to 5.4.
9. pH at the end of the test for solution A shall not exceed 4.0 while solution B, the pH should be in the range of 4.8 to 5.4.
10. The test duration is 96 hours which begin immediately after the initial 60mins H2S introduction period.
11. The temperature during the test shall be maintained at 25ºC



1. After testing, the specimen shall be cut into pieces as shown in the figure 3.3 and 3.4.


2. Each section shall be polished metallographically and etched to distinguish between crack and other defects such as inclusion, lamination and scratches. Prior to polish the samples, all faces shall be examined under the scope. After polishing, crack shall be visible if present. For any crack, it will be measured for the length and thickness as shown in figure below





4.0 OBSERVATION/ FINDING
The testing has successfully been done. All of the procedures were complied and conform accordingly. The samples were taken out at 1230 hour from the test vessel after 96 hours by the personnel with fully PPE to avoid the noxious of H2S gas. All the samples were washed to remove the chemical on the samples. Next, the lab personnel punch the numbers for identification prior to cutting process. After cut into pieces, the faces were ground using abrasive paper. After obtain the clear shiny surface, all the samples were examine under a scope using low magnification to identify any crack or other defects. Once finished, the samples were then polished using the alumina solution and polishing cloth until obtain the mirror like surface. The samples were once again examine under a scope before etch using 2% nitrate acid to reveal the microstructure of the surfaces. Each of the samples was examine at 100x magnification and the micrographs of the samples were saved as data for report purposes.
As per my observation and random check, there is only one visible crack was found on the samples but it’s within the allowable range. The testing was adjourned at 1700 hour.


5.0 CONCLUSION
From the HIC witness test, I’ve learn the procedure of HIC (Hydrogen Induced Cracking) and the measurement and calculation of crack. Procedure of HIC testing is based on NACE TM 0284 & NACE TM 0177. For the acceptance criteria, this testing was followed (Linepipe for oil and gas for sour service) standard. The acceptance criteria for CLR is 15% max, CSR 1.5% max and CTR 5% max.




Reference
Standard Test Methods
• NACE TM0177 - laboratory testing of metals for resistance to sulfide stress cracking in H2S environments.
• NACE TM0284 - evaluation of pipeline and plate steels for resistance to stepwise cracking.
• ASTM G129 - slow strain rate test for determination of environmentally assisted cracking.
• ASTM G142 - tension tests in hydrogen environments.
• ASTM G146 - hydrogen induced disbonding of stainless clad steel plate in refinery hydrogen service.
• ASTM F-326 - method for electronic hydrogen embrittlement test for cadmium electroplating processes.
• ASTM F-519 - method for mechanical hydrogen embrittlement testing of plating processes and aircraft maintenance chemicals.
• ASTM A-143 - practice of safeguarding against embrittlement of hot dip galvanized structural steel products and detecting embrittlement.
• ASTM B-577 - hydrogen embrittlement of deoxidized and oxygen free copper.
Evaluation for Hydrogen Induced Damage
Since hydrogen can induce many types of damage in engineering materials, it’s impossible to look to only one test method for all problems.
• Slow strain rate test methods are good to obtain general information on the inherent susceptibility to hydrogen embrittlement is a short period of time. However, the results will generally be very conservative.
• For higher strength materials, the use of constant load tests for determination of an apparent threshold stress for cracking is a generally accepted technique.
• Hydrogen induced cracking and blistering of low strength steels can be tested using non-stressed coupons exposed to the test environment. However, in some cases, the addition of an externally applied or residual tensile stress can cause materials to crack that do not show cracking in the non-stressed condition. Also, constant load specimens may not fail under tensile stress even though they may have extensive internal cracking or blistering.
High temperature hydrogen damage and disbonding must be evaluated for the specific conditions of time and temperature for the intended use. However, it can in many cases, be accelerated with the combination of higher temperature and/or hydrogen pressure.

Material Corrosion Engineering - Failure Analysis/ Welding Technology

Failure Analysis

Non-destructive Test (NDT)

Visual inspection

Direct visual inspection

A visual examination of operational plant can be used to check for obvious problem areas, such as leaks, excess vibration or misalignment. On exposed metal surfaces it can also be used to check for corrosion. Specific guidance on the inspection of pressure vessels for corrosion and other flaws is given in API Recommended Practice 572, and on the inspection of piping, valves and fittings associated with pressure vessels in API Recommended Practice 574.
Plant coated with internal or external coverings, such as insulation, refractory protective linings and corrosion resistant linings, may be inspected visually if access permits. In such cases, a visual examination can be used to check that the protective layer has not separated and that it is free of breaks, holes and blisters.
In some extreme cases, a visual examination may also be able to detect cracking, particularly if the cracking is surface-breaking and extensive. There are various aids to visual inspection. As well as magnifying glasses, there are devices for measuring pit depths, weld leg length and surface profiles.
Visual examination is applicable to most surfaces, but is most effective where the surfaces have been cleaned prior to examination, i.e. any scale, loose paint has been removed by wire brushing etc. However, care must be taken to avoid peeling.
Remote visual inspection

An enhanced visual inspection using boroscopes or endoscopes can be used to check the internal surfaces of pipes or tubes for corrosion and/or erosion damage. On pipe containing a protective inner lining, boroscopes may be used to check that the lining is free of breaks, holes and blisters. Also, if the inner surface of the pipe or tube is sufficiently clean, boroscopes may be able to detect surface-breaking cracks, provided that they are sufficiently large.
Where access is restricted, and it is not possible to examine the subject area with the naked eye, boroscopes or endoscopes may be used. In simple terms, these are telescopes, which can be inserted into pipes, tubing or access holes in machinery. Most modern endoscopes use optical fibers to illuminate the subject area and to relay the image back to a closed-circuit television camera. Optical fibers enable images to be retrieved over several meters and permit access to relatively complex geometries. The inspection can also be recorded on video. Equipment costs range from a few hundreds of pounds for a manually operated endoscope to several thousand for a sophisticated video recording system.
Boroscopes and endoscopes are normally used to examine areas that are inaccessible to the naked eye. Perhaps, their most common application area is the examination of small diameter tube or pipe.

Radioactive testing

RT is a method of inspecting materials for hidden flaws by using the ability of short wavelength electromagnetic radiation, which are high energy photons to penetrate various materials. Since the amount of radiation emerging from the opposite side of the material can be detected and measured, variations in this amount or intensity of radiation are used to determine thickness or composition of material. In RT, we use ASME V and PTS 20.112 to determine the RT quality and its area of concern.


Ultrasonic Testing (UT)

Ultrasonic Testing (UT) uses high frequency sound energy to conduct examinations and make measurements. Ultrasonic inspection can be used for flaw detection/evaluation, dimensional measurements, material characterization, and more. To illustrate the general inspection principle, a typical pulse/echo inspection configuration as illustrated below will be used.
A typical UT inspection system consists of several functional units, such as the pulser/receiver, transducer, and display devices. A pulser/receiver is an electronic device that can produce high voltage electrical pulses. Driven by the pulser, the transducer generates high frequency ultrasonic energy. The sound energy is introduced and propagates through the materials in the form of waves. When there is a discontinuity (such as a crack) in the wave path, part of the energy will be reflected back from the flaw surface. The reflected wave signal is transformed into an electrical signal by the transducer and is displayed on a screen. In the applet below, the reflected signal strength is displayed versus the time from signal generation to when an echo was received. Signal travel time can be directly related to the distance that the signal traveled. From the signal, information about the reflector location, size, orientation and other features can sometimes be gained.



Ultrasonic Inspection is a very useful and versatile NDT method. Some of the advantages of ultrasonic inspection that are often cited include:
• It is sensitive to both surface and subsurface discontinuities.
• The depth of penetration for flaw detection or measurement is superior to other NDT methods.
• Only single-sided access is needed when the pulse-echo technique is used.
• It is highly accurate in determining reflector position and estimating size and shape.
• Minimal part preparation is required.
• Electronic equipment provides instantaneous results.
• Detailed images can be produced with automated systems.
• It has other uses, such as thickness measurement, in addition to flaw detection.
As with all NDT methods, ultrasonic inspection also has its limitations, which include:
• Surface must be accessible to transmit ultrasound.
• Skill and training is more extensive than with some other methods.
• It normally requires a coupling medium to promote the transfer of sound energy into the test specimen.
• Materials that are rough, irregular in shape, very small, exceptionally thin or not homogeneous are difficult to inspect.
• Cast iron and other coarse grained materials are difficult to inspect due to low sound transmission and high signal noise.
• Linear defects oriented parallel to the sound beam may go undetected.
• Reference standards are required for both equipment calibration and the characterization of flaws.
The above introduction provides a simplified introduction to the NDT method of ultrasonic testing. However, to effectively perform an inspection using ultrasonic’s, much more about the method needs to be known. The following pages present information on the science involved in ultrasonic inspection, the equipment that is commonly used, some of the measurement techniques used, as well as other information.

Advantages
1. High penetrating power, which allows the detection of flaws deep in the part.
2. High sensitivity, permitting the detection of extremely small flaws.
3. Only one surface need be accessible.
4. Greater accuracy than other nondestructive methods in determining the depth of internal flaws and the thickness of parts with parallel surfaces.
5. Some capability of estimating the size, orientation, shape and nature of defects.
6. Nonhazardous to operations or to nearby personnel and has no effect on equipment and materials in the vicinity.
7. Capable of portable or highly automated operation.

Disadvantages
1. Manual operation requires careful attention by experienced technicians
2. Extensive technical knowledge is required for the development of inspection procedures.
3. Parts that is rough, irregular in shape, very small or thin, or not homogeneous are difficult to inspect.
4. Surface must be prepared by cleaning and removing loose scale, paint, etc, although paint that is properly bonded to a surface usually need not be removed.
5. Couplants are needed to provide effective transfer of ultrasonic wave energy between transducers and parts being inspected unless a non-contact technique is used. Non-contact techniques include Laser and Electro Magnetic Acoustic Transducers (EMAT).
6. Inspected items must be water resistant, when using water based couplants that do not contain rust inhibitors.

Specimen Preparation

Band Saw

A band saw is used basically in metalworking industry which is particularly useful for cutting both irregular or curved shapes and straight cut work pieces. This machine contains a power tool which utilizes a blade consisting of a continuous band of metal with teeth along one edge. The band is riding on two wheels rotating in the same plane. The saw is powered by electrical motor and produces uniform cutting action as a result of an evenly distributed tooth load. The radius of a curve that can be cut on a particular saw is determined by the width of the band and its lateral flexibility. Figure 2.6 shows the band saw blades.





Horizontal band saws may employ a gravity-fed blade or the cutting rate may be controlled by a hydraulic cylinder bleeding through an adjustable valve. Before the operations start, the operator raises the saw by hand and the material is clamped in place. When the saw is turned on, the blade slowly descending into the material, cutting it as the band blade moves. When the cutting process is complete, a switch is tripped and the saw automatically turns off. Sometimes, the brushwheels are used to remove chips away from the workpieces.
For EU-250AR, Hydraulic Vise Fully Automatic Band Saws has the medium size of 10” professional band saws. The Way Train product has a wide range of applications including processing large steel H beams and heavy steel mold forms. The blade size is 27mm x 0.9mm x 3300mm while the blade speed range is between 20mpm until 80mpm which is controlled by 2.0 hp motor. The overall band saw is controlled by hydraulic motor with 0.5 hp and the coolant motor is 0.2 hp. Figure 2.7 shows the horizontal band saw.





Horizontal band saw

Sample Preparation

The technique of sample preparation for metallurgical lab practices is an essential procedure. These samples will be examined and photomicrographs are obtained by using optical microscopes equipped with digital cameras. There are four steps in sample preparation technique which are mounting, grinding, polishing and etching.
Mounting
Small specimens generally require mounting so that the specimen is supported in a stable medium for grinding and polishing. The time, Th (curing temperature), and Tc (cooling temperature) are set on the mounting machine according to the required application. Then, the sample is loaded in the machine. The pressure is set according to the required application, and the process is started.
Grinding
Grinding is a finishing process used to improve surface finish, abrade hard materials, and tighten the tolerance on flat and cylindrical surfaces by removing a small amount of material.
In grinding, an abrasive material rubs against the metal part and removes tiny pieces of material. The abrasive material is typically on the surface of a wheel or belt and abrades material in a way similar to sanding. On a microscopic scale, the chip formation in grinding is the same as that found in other machining processes. The abrasive action of grinding generates excessive heat so that flooding of the cutting area with fluid is necessary. Grinding can produce flatness tolerances of less than ±0.0025 mm on steel surface if the surface is adequately supported. Other than that, grinding is able to remove excessive material. Figure 2.8 shows the grinding process chart which contains of several types of grit grinding starting from the least abrade surface until most abrade surface. Figure 2.9 shows the example of grit grinding wheel.






Polishing

The term mechanical polishing is frequently used to describe the various final polishing procedures involving the use of cloth-covered laps and suitable polishing abrasives. The laps have either a rotating or a vibrating motion, and the specimen are held by hand, held mechanically, or merely confined within the polishing area.

Polishing is done in a relatively dust-free area, preferably removed from the area for sectioning, mounting and rough grinding. Any contamination of a polishing lap by abrasive particles carried over from a preceding operation or by dust, dirt or other foreign matter in the air cannot be tolerated. Carryover as a result of improper cleaning between final polishing steps is another prime source of contamination. It is just as important for the operator to wash his hand meticulously as is for him to remove all traces of polishing abrasive from the specimen before proceeding to the next polishing operation. The specimen can be cleaned ultrasonically or by careful washing under running water and swabbing with cotton. In automatic equipment in which holding fixtures for the specimens are also transferred through successive polishing steps, proper cleaning of the assembly can be accomplished only by using an ultrasonic cleaner.

If a polishing lap becomes contaminated, it is virtually impossible to remove all of the contaminant by washing the polishing cloth. Instead, the operator should replace the cloth and use fresh polishing solution. Cleanness cannot be overemphasized. It takes only one particle of grit on a final polishing lap to ruin all prior preparation.









Etching

Etching of the sample is performed to reveal to grain structure and other features on the sample. Prior to etching, the grain structure and other features are unobservable. In the etching stage, the polished sample is exposed to the corrosive chemical. The chemical will attack the surface especially on the weaker bonded atoms. Any atoms at the grain boundary are removed at higher rate. As a result, the grain boundary becomes deeper and looks darker than the grain. The impurities react differently on the chemical and distinguished themselves away. There several procedures regarding the etching technique. The gloves are worn while using these caustic etchants. The time is set and the surface is covered with etchant. After several moments, the etchant is rinsed off with distilled water when proper etching time is reached. It is advisable not to dry the sample by wiping, because this will scratch the polished sample.


Brinell Hardness Test

Hardness tests are performed more frequently than any other mechanical test for several reasons. No special specimen needs to be prepared, and the testing apparatus is relatively inexpensive. The test is non-destructive where the specimen is neither fractured nor excessively deformed. A small indentation is the only deformation. Other mechanical properties may be obtained from the hardness data, such as tensile strength.

In Brinell test, a hard, spherical indenter is forced into the surface of the metal to be tested. The diameter of the indenter is 10.00 mm (0.394 inn.). Standard loads range between 500 kg until 3000 kg in 500-kg increments. Harder materials require greater applied loads. During a test, the load is maintained constant between 10 s and 30 s. The Brinell hardness number, HB is a function of both the magnitude of the load and the diameter of resulting indentation. This diameter is measured using a special low-power microscope. Figure 2.10 shows the Brinell Test equipment.







Stereo Microscope
The stereo or dissecting microscope uses two separate optical paths with two objectives and two eyepieces to provide slightly different viewing angles to the left and right eyes. In this way it produces a 3-D visualization of the sample being examined. The function of this type of microscope is to study the surfaces of solid specimens or to carry out close work such as sorting, dissection, microsurgery, watch-making, small circuit board manufacture or inspection. The illumination in a stereo microscope most often uses episcopic (reflected) illumination rather than diascopic (transmitted) illumination, that is, light reflected from the surface of an object rather than light transmitted through an object. Use of reflected light from the object allows examination of specimens that would be too thick. However, stereo microscopes are also capable of transmitted light illumination as well, typically by having a bulb or mirror beneath a transparent stage underneath the object
The Stemi SV 11 is used primarily for searching and sorting embryos. The heated stage can be added as an option. Standard configuration for Stemi SV 11 includes SV 11 Apo stereo microscope body, fine focusing mount, binocular 35 degree tube, 10x focusing eyepieces, folding eyecups, type N Stand (32mm column) and dust cover. The microscope has maximum magnification of 60 times. Figure XX shows the Stemi SV 11 Stereo Microscope.








Stemi SV 11 Stereo Microscope

Scanning Electron Microscope (SEM)
The SEM is an instrument that produces a large magnified image by using electrons instead of light to produce an image. Philips XL40 SEM is used to detect fracture surface on the material. The magnification of the microscope can reach until 100,000 times. Philips XL40 SEM is assisted by EDX software that can detect any source of corrode mechanisms. For example, any foreign elements can be detected in steel.

A beam of electrons is produced at the top of the microscope by an electron gun. The electron beam follows a vertical path through the microscope, which is held within a vacuum. The beam travels through electromagnetic fields and lenses, which focus the beam down toward the sample. Once the beam hits the sample, electrons and X-rays are ejected from the sample. Detectors collect these X-rays, backscattered electrons, and secondary electrons and convert them into a signal that is sent to a screen similar to a television screen. This produces the final image.
Because the SEM utilizes vacuum conditions and uses electrons to form an image, special preparations must be done to the sample. All water must be removed from the samples because the water would vaporize in the vacuum. All metals are conductive and require no preparation before being used. All non-metals need to be made conductive by covering the sample with a thin layer of conductive material. This is done by using a device called a ‘sputter coater’.
The sputter coater uses an electric field and argon gas. The sample is placed in a small chamber that is at a vacuum. Argon gas and an electric field cause an electron to be removed from the argon, making the atoms positively charged. The argon ions then become attracted to a negatively charged gold foil. The argon ions knock gold atoms from the surface of the gold foil. These gold atoms fall and settle onto the surface of the sample producing a thin gold coating. If there is no sputter coater being used on non-metal samples, the produced image will be discharged.















3.0 Welding
3.1 Welding Procedures

Table 3.1: Types of welding procedure
Gas Tungsten Arc Welding (GTAW) Gas Metal Arc Welding (GMAW) Flux Cored Arc Welding (FCAW)
Other name Tungsten Inert Gas (TIG) welding Metal Inert Gas (MIG) welding “Dual Shield” welding
Mechanism Uses an electric arc between a tungsten electrode (non-consumable) and the workpiece to produce the weld
Uses the heat of an electric arc between a continuous filler metal electrode and the workpiece to produce the weld
Same as GMAW
Shielding inert gas/ inert gas mixture i.e. Argon externally supplied gas or gas mixture usually CO2 Flux-cored electrode and an extra shielding gas
Power Supplies Has both DC and AC current DC DC
Applicability Commonly to weld thin sections of stainless steel and non-ferrous metals Mainly for welding carbon and low-alloy steels, stainless steels, heat-resisting alloys, aluminum alloys etc. Mainly for welding carbon and low-alloy steel
Advantages The smaller the thickness is better: usually <2”, easier for operator to control
Often permits economies in the total weld volume required because it is semi-automatic
• In closed environment can produce better and more consistent mechanical properties of welds with fewer defects as compared to either SMAW or GMAW.
• The slag created by the flux is also easy to remove.

Weakness • Relatively difficult to master
• Need proper control of welding current
• More time consuming than other techniques Porosity due to gas entrapped or generated in the weld, often caused by improper gas shielding Not suitable in windy environments as the loss of shielding gas from air will produce visible porosity on surface of the weld


GTAW GMAW FCAW


Shielded Metal Arc Welding (SMAW)

Shielded Metal Arc Welding (SMAW) is defined as "an arc welding process in which coalescence of metals is produced by heat from an electric arc that is maintained between the tip of a flux covered electrode and the surface of the base metal in the joint being welded." This process forms the gas and slag to shield the arc and molten weld pool. The slag must be chipped off the weld bead after welding. The flux also provides a method of adding scavengers, deoxidizers, and alloying elements to the weld metal. This process is commonly referred to as stick welding.


Equipment required to perform the SMAW welding process includes a constant current power source that supplies the power to the consumable rod electrode.
The SMAW welding process typically is capable of producing three types of welded joints. They are:
 Butt joint
 Lap joint,
 T-joint, and
 Fillet weld.

Advantages Limitations /Disadvantages
• Versatility - readily applied to a variety of applications and a wide choice of electrodes
• Relative simplicity and portability of equipment
• Low cost
• Adaptable to confined spaces and remote locations
• Suitable for out-of-position welding • Not as productive as continuous wire processes
• Likely to be more costly to deposit a given quantity of metal
• Frequent stop/starts to change electrode
• Relatively high metal wastage (electrode stubs)
• Current limits are lower than for continuous or automatic processes (reduces deposition rate)




Submerged Arc Welding (SAW)

Submerged Arc Welding is defined as "a process which produces coalescence of metals by heating them with a buried arc between a bare electrode and the work. The arc and molten metal are "submerged" in a blanket of granular fusible flux on the work." This process is often referred to as Sub-Arc.

This process most commonly uses a continuous, consumed, bare solid wire electrode that is shielded by the flux. The flux acts to stabilize the arc during welding, shielding the molten pool from the atmosphere. Additionally the flux covers and protects the weld during cooling and can affect weld composition and properties. The weld metal properties will vary based on the flux and consumable wire selection.


SAW process





Advantages Limitations /Disadvantages
• Very high welding rate-High deposition rate
• The process is suitable for automation-High operating factors
• High quality welds structure.
• Deep weld penetration
• Good process design and control
• Minimal welding fume or arc light is emitted.
• Suitable for both indoor and outdoor
• Welds produce are sound, uniform, ductile, corrosion resistant and have good impact value. • Weld may contain slag inclusions
• Limited applications of the process - mostly for welding horizontally located plates.
• Limited to ferrous (steel or stainless steel) and some nickel based alloys.
• Limited to the 1F, 1G, and 2F positions.
• Requires inter-pass and post weld removal.
• Normally limited to long straight seams or rotated pies vessels.



SAW machine


Figure 3.4: SAW Torch
3.4 Welding Positions
Welding Positions for Groove welds:
Welding Position Test Position ISO and EN
Flat 1G PA
Horizontal 2G PC
Vertical Upwards Progression 3G PF
Vertical Downwards Progression 3G PG
Overhead 4G PE
Pipe Fixed Horizontal 5G PF
Pipe Fixed @ 45 degrees Upwards 6G HL045
Pipe Fixed @ 45 degrees Downwards 6G JL045


Welding Positions for Fillet welds:
Welding Position Test Position ISO and EN
Flat (Weld flat joint at 45 degrees) 1F PA
Horizontal 2F PB
Horizontal Rotated 2FR PB
Vertical Upwards Progression 3F PF
Vertical Downwards Progression 3F PG
Overhead 4F PD
Pipe Fixed Horizontal 5F PF















Welding positions for Plate and Pipes

IMPACT TEST

Charpy Impact Test
Charpy impact test is used to measure the impact energy, sometimes also called notch toughness. The specimen is in the shape of a bar of square cross section, into which a V-notch is machined. The apparatus for making V-notch is shown in the figure below. The load is applied as an impact blow from weight pendulum hammer that is released from a cocked position at a fixed height h. Upon release, a knife edge mounted on the pendulum strikes and fractures the specimen at the notch, which acts as a point of stress concentration for this high-velocity impact blow. The pendulum continues its swing, rising to a maximum height h’, which is lower than h. The energy absorption, computed from the difference between h and h’. This test determines the fracture properties of a material.

The notch in the sample affects the results of the impact test, thus it is necessary for the notch to be of a regular dimensions and geometry. The size of the sample can also affect results, since the dimensions determine whether or not the material is in plane strain. This difference can greatly affect conclusions made.
The quantitative result of the impact test—the energy needed to fracture a material—can be used to measure the toughness of the material and the yield strength. Also, the strain rate may be studied and analyzed for its effect on fracture.
The qualitative results of the impact test can be used to determine the ductility of a material. If the material breaks on a flat plane, the fracture was brittle, and if the material breaks with jagged edges or shear lips, then the fracture was ductile. Usually a material does not break in just one way or the other, and thus comparing the jagged to flat surface areas of the fracture will give an estimate of the percentage of ductile and brittle fracture.
According to ASTM A370, the standard specimen size for Charpy impact testing is 10mm×10mm×55mm. Subsize specimen sizes are: 10mm×7.5mm×55mm, 10mm×6.7mm×55mm, 10mm×5mm×55mm, 10mm×3.3mm×55mm, 10mm×2.5mm×55mm. Details of specimens as per ASTM A370 (Standard Test Method and Definitions for Mechanical Testing of Steel Products).


Bend Test
Many welding codes require bend tests as part of the testing required to qualify welders and welding procedures specifications (WPSs). The concept of a bend test for welds is simple: two plates are welded together and a flat strap of metal is cut from the welded plates. Next, the flat strap of a prescribed size is bent into a U-shape, stretching the material on the outer surface of the "U," while compressing the material on the inside surface.
The purpose is to make certain the weld and the base metal are properly fused, and that the weld metal and the heat affected zone (HAZ) have appropriate mechanical properties.
Although bend tests appear to be simple, any number of things can cause good welding procedure specifications or good welders to fail. The person responsible for accepting or rejecting test results must understand those factors, and know how to correct for any that are causing inappropriate failure.
Bend specimens have been called "a poor man's tensile test." Although it will not show the quantitative values associated with a tensile test, a bend test will demonstrate both the quality of the weld and its overall ductility. Usually, bend tests are designed so that the outer surface of the specimen is stretched to a ductility level that approximates the minimum percent elongation required in a tensile test. When defects exist in materials strained to these limits, the material tears locally. When tearing exceeds a specific limit, the specimen fails.




Nick Break Test

The Nick Break test is useful for determining the internal quality of the weld metal. This test reveals various internal defects (if present), such as slag inclusions, gas pockets, lack of fusion, and oxidized or burned metal. The specimen for a nick-break test is notched on two sides at the center of the weld and then the specimen is broken by a sharp blow. Examination of the exposed surfaces will indicate any inclusions, lack of fusion, or other similar defects that extend through that section of the weld through which the break progresses.

Saturday, May 1, 2010

Hommies trip to Melaka...


Gamba time makan2 at wedding hall




This is our first time visiting melaka together just in the first place just to attend Mona's sister wedding at Masjid tanah...but, before that...i just received invitation in da morning before we went there...haha..adil lambat bgtau maa....seb baik xde keje...so, we start our journey at 2pm due to unavoided situation where we all didnt bring camera for the trip...that needed adil to take his company camera....hahaha...ape2 la adil..at 330pm, we arrived at Masjid Tanah...so ok...our stomach dah penuh ngan angin...after salam2 with his parent..trus g amik makanan...ape la ktorg..but that time few people left..so doing slamba jela...after chit chat and photo session at the weeding hall...Mona ask to stay at his late grandfather house...haha..for us is no need la..cam segan lak nak datang umah time org penat after kenduri...then just 'what if we lepak2 and solat at Masjid area...so...hommies gangs vote just to lepak2 at surau..lagepon bagus what..meriahkan surau kan...









so, bab solat done..hehe..b4 that..hehe..i've made an investment (pelaburan) at surau place...hehehe..sory beb..perut not so comfortable...hehehe..butterflies in my stomach..hehe






huh ..lega after big investment...then we went for jalan2 n photo session at 'sawah' area...actually ex -sawah...org kampung now just buy rise at shop..hehehe...xde dah nak tanam sendiri..hehe...for me, i just want to catch fist at bendang area..coz didnt have that opputunity before...hehe...so after posing here n there...we siap2 mau g umbai where mona voluntarry want to belanja us..hehe..wow ikan bakar or sotong bakar...terliur gua






journey form Masjid Tanah to Umbai barely take 2 hours...due to traffic jamm...demmit...lucky for me coz i'm just a co driver..so adil n me just released tension due to jamm by karok all da way..hehe...it was fun to karok while other look like tension and we like crazy people shounting n make funny face with ecah others..choi...hahak..






skip...so sampai at umbai..trus cari meja..then we order...(im just waiting at table la...yang order kucai n laen2)...shocked they ordered 2 siakap, 2 jenahak, 4 kilos sotong aka squid, kepah , n pari paiz...haha..it like sial gler makan banyak camtu..haha,...but most important things that we enjoyed that night and definitely we will have that makan besar next time..hoho..