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BULK STORAGE TANK
OVERVIEWS
TO DETERMINE THE MATERIAL, FOLLOWING DATA IS REQUIRED: -
1. GRADE2. CLASS3. TYPE4. SPECIFICATION
GRADE REQUIREMENT: -
GRADE SUBSTITUTION OCCURS WHEN: -
MATERIAL CONTAINS AN ELEMENT THAT IS SPECIFIED FOR ONE OF THE GRADE.THE AMOUNT OF THAT ELEMENT PRESENT IN MATERIALS MEET THE MIN & MAX COMPOSITION LIMIT FOR ELEMENT IN ANOTHER GRADE.
SPECIFICATION REQUIREMENT
TO FIND THE MATERIAL THAT IS SUITABLE FOR MANUFACTURING A PRODUCT OR NOT WE REQUIRE THIS SPECIFICATION.
NAME OF ORGANISATION, WHICH DESCRIBES THE CODES FOR ALL ELEMENTS: -
ASME-----------------------AMERICAN SOCIETY OF MECHANICAL ENGINEERS
ANSI------------------------AMERICAN NATIONAL STANDARD INSTITUTE
ASTM-----------------------AMERICAN SOCIETY FOR TESTING AND MATERIALS
IS -----------------------INDIAN STANDARDS
BULK STORAGE TANK FOR COCHIN SHIPYARD LIMITED
“ MATERIAL REQUIRED & THEIR SPECIFICATION”
MATERIAL SPECIFICATION
DOUBLING PLATE NV-2
AIR SLIDE NV-2
ENTRY HANDLE NV-2
NAME PLATE NV-2
DRAIN ARRANGEMENT NV-2
LADDER NV-2
SUPPORT OF DISH PIPE SA106GrB
HATCH DRGS: 413-364-C
REDUCER ASTM A106GrB
BEND SA106GrB
PIPE SA106GrB
SOCKET ST.52
SOCKET ST.52
SOCKET ST.52
PIPE SA106GrB
FLANGE ST.37
BLIND FLANGE ST.37
BLIND FLANGE ST.37
HEXAGON BOLT & NUT ST.37
PIPE SA106GrB
DOUBLING PLATE NV4-2
PILLAR CAP NVA
LIFTING EYE ST.52
TORISPHERICAL TOP NV4-2
CYLINDER UPPER PART NV4-2
CYLINDER LOWER PART NV4-2
TORISPHERICAL BOTTOM NV4-2
SPECIFICATION FOR CARBON STEEL FORGING FOR PIPING APPLICATION
SA-105/SA-105M
THIS SPECIFICATION COVERS FORGED CARBON STEEL PIPING COMPONENT FOR AMBIENT AND HIGHER TEMPERATURE SERVICE IN PRESSURE SYSTEM.THIS SPECIFICATION INCLUDE ALL FLANGE, FITTING FOR VALVES.
CHEMICAL COMPOSITION
ELEMENT COMPOSITION (%) GRADE B
CARBON 0.35
MANGANESE 0.60
SULPHER 0.35
SILICON .010-0.35
COPPER 0.40
NICKEL 0.40
MOLYBDENUM 0.12
CHROMIUM 0.30
VANADIUM 0.05
TENSILE STRENGTH 485Mpa
YIELD STRENGTH 250Mpa
SPECIFICATIONS FOR SEAMLESS CARBON STEEL PIPE FOR HIGH TEMPERATURE SERVICE
SA-106 / SA-106MTHIS SPECIFICATION COVERS SEAMLESS CARBON STEEL PIPE FOR HIGH TEMPERATURE SERVICES.PIPE ORDERED UNDER THIS SPECIFICATION ARE SUITABLE FOR BENDING, FLANZING & FOR WELDING PROCESS.
CHEMICAL REQUIREMENT
ELEMENT COMPOSITIONS (%), GRADE B
CARBON, MAX 0.30
MANGANESE 0.29
PHOSPHORUS 0.035
SULPHUR, MAX 0.035
SILICON, MIN 0.10
CHROME, MAX 0.40
COPPER, MAX 0.40
MOLYBDENUM, MAX 0.15
NICKEL, MAX 0.40
VANADIUM 0.08
SPECIFICATION FOR ALLOYS STEEL & STAINLESS STEEL BOLTING MATERIAL SUITABLE FOR HIGH TEMPERATURE SERVICES
SA-193 /SA-193M
THIS SPECIFICATION COVERS ALLOYS & STAINLESS STEEL BOLTING MATERIAL FOR PRESSURE VESSEL, VALVES, BOLTS, SCREW, STUDS BOLTS ALLOYS STEEL BOLTING MATERIALS SUITABLE FOR USE IN LOW TEMPERATURE APPLICATON.
CHEMICAL COMPOSITION
ELEMENT COMPOSITION
CARBON 0.10
MANGANESE 1.00
PHOSFUR 0.040
SILICON 1.00
CHROMIUM 4.0-6.0
MOLYBDENUM 0.40-0.60
SPECIFICATION FOR PRESSURE VESSEL PLATE, CARBON STEEL, FOR MODERATE & LOWER TEMPERATURE SERVICE
SA-516 / SA-516M
THIS SPECIFICATION COVERS CARBON STEEL PLATE INTENDED PRIMARILY FOR SERVICE IN WELDED PRESSURE VESSEL WHERE NOTCH TOUGHNESS IS IMPORTANT.THE MAXIMUM THICKNESS OF PLATE IS LIMITED ONLY BY THE CAPACITY OF COMPOSITION TO MEET THE SPECIFIED MECHANICAL PROPERTY REQUIREMENT. NORMALLY LIMITS THE MAXIMUM THICKNESS OF PLATES FURNISHED THIS SPECIFICATION.
GRADE, U.S (SI) MAXIMUM THICKNESS IN (mm)
55 ( 380 ) 12 MM
60 ( 415 ) 8 MM
65 ( 450 ) 8 MM
70 ( 485 ) 8 MM
CHEMICAL COMPOSITION
ELEMENTS COMPOSITION (%)
CARBON 0.18
MANGANESE 0.60-0.90
PHOSPHORUS 0.035
SULFUR 0.035
SILICON 0.15-0.40
TENSILE STRENGTH 380-515 MPA
YIELD STRENGTH 205 MPA
SPECIFICATION FOR PRESSURE VESSEL PLATE, ALLOYS STEEL, HIGH STRENGTH, QUENCHED & TEMPERED
SA-517 / SA-517 M
THIS SPECIFICATION COVERS HIGH STRENGTH QUENCHED AND TEMPERED ALLOYED STEEL PLATE INTENDED FOR USE IN WELDED BOILERS AND PRESSURE VESSEL.
CHEMICAL COMPOSITION
ELEMENTS COMPOSITION (%), GRADE ‘B’
CARBON 0.15-0.21
MANGNESE 0.70-1.00
PHOSPHORUS 0.035
SILICON 0.15-0.35
NICKEL 0.15-0.35
CHROMIUM 0.40-0.65
TENSILE STRENGTH 795-930 MPA
YIELD STRENGTH 690 MPA
SPECIFICATION FOR CARBON STEEL ELECTRODES FOR SHIELDED METAL ARC WELDING
GRADE – 1SFA – 5.1
THIS SPECIFICATION PRESCRIBES REQUIREMENT FOR CLASSIFICATION OF CARBON STEEL ELECTRODES FOR SMAW.
THE WELDING ELECTRODE COVERED BY THIS SPECIFICATION ARE CLASSIFIED ACCORDING TO THE FOLLOWING
1. TYPE OF CURRENT 2. TYPE OF COVERING
2. WELDING POSITION
MECHANICAL PROPERTIES OF WELD METAL IN WELDED CONDITION,MATERIAL CLASSIFIED UNDER ONE CLASSIFICATION SHALL NOT BE CLASSIFIED UNDER ANY OTHER CLASSIFICATION OF THIS SPECIFICATION EXCEPT THAT E7018M MAY ALSO BE CLASSIFIED AS E7018 PROVIDED THE ELECTRODE MEET ALL REQUIREMENT OF BOTH CLASSIFICATION.
AWS CLASSIFICATION TYPE OF COVERING WELDING POSITION CURRENT E7018 LOW HYDROGEN “K”IRON POWDER F,V,H AC OR DC
E7018 LOW HYDROGEN IRON POWDER F,V,OH,H DC
SPECIFICATION FOR CARBON STEEL ELECTRODES AND FLUX FOR SUBMERGED ARC WELDING
SFA - 5.17
THIS SPECIFICATION PRESCRIBE REQUIREMENT FOR CLASSIFICATION FOR CARBON STEEL ELECTRODE (BOTH SOLID & COMPOSITION) AND FLUX FOR SAW.
“M” IS APPLICABLE ONLY TO THOSE PRODUCT CLASSIFIED TO THE SYSTEM BASED UPON THE INTERNATIONAL SYSTEM OF UNIT (SI) UNDER THE 5.17M SPECIFICATION.
MANDATORY CLASSIFICATION DESIGNATORS
S F * * * - C * * * - H *
S--------------INDICATE THE WELDING FLUX BEING CLASSIFIED IS MADE SOLELY FROM CRUSHED SLAG WITH UNUSED FLUX.OMISSION OF “S” INDICATE THAT THE FLUX BEING CLASSIFIED IS VIRGIN FLUX.
F---------------INDICATE A SUBMERGED ARC WELDING FLUX
***------------INDICATE MIN TENSILE STRENGTH OF WELD METAL DEPOSITED
EC-------------CLASSIFICATION OF ELECTRODE USED IN PRODUCING THE WELD METAL, THE FIRST LETTER “ E” INDICATE THE ELECTRODE & “C” INDICATE COMPOSITE ELECTRODE.
***-------------INDICATE THE TEMPERATURE
H---------------OPTIONAL SUPPLEMENTAL DESIGNATOR, DIFFUSIBLE HYDROGEN DESIGNATOR
ELECTRODE FOR DIFFERENT TYPE OF WELDING
TIG (TUNGSTON INERT GAS WELDING)---------------AWS /SFA 5.9:ER316L
STAINLESS STEEL ARC WELDING----------------------AWS /A 5.1: E 6013
SMAW------------------------------------------------------SA516 GR70/ SA106GR B
MIG---------------------------------------------------------SA516 GR B
BULK STORAGE TANK
(COCHIN SHIPYARD LIMITED)
OVERVIEWS
MATERIAL REQUIRED CARBON STEEL PLATE OR MILD STEEL
COST OF ONE TANK RS 7,86,450.00
DIMENSIONS ACCORDING TO DRAWING OF BULK STORAGE TANK
CARBON STEEL PLATE THICKNESS 12 MM
DISH TOP SIDE THICKNESS 22 MM
DISH BOTTOM SIDE THICKNESS 26 MM
DIAMETER OF TANK 4300 MM DIAMETER OF MANHOLE 560 MM
LENGTH OF TANK 9144 MM
WEIGHT OF BULK STORAGE TANK 14800 KG
DISH HEIGHT FROM UPPER PORTION 907 MM
DISH HEIGHT FROM LOWER PORTION 907 MM
MIDDLE PORTION HEIGHT 3635 MM
TOTAL HEIGHT OF BULK STORAGE TANK 5733MM
HEIGHT OF UPPER CARBON STEEL PLATE 2435 MM
HEIGHT OF LOWER CARBON STEEL PLATE 1200 MM
DESIGN – DATA
WORKING PRESSURE 5.6 BAR
DESIGN PRESSURE 5.8 BAR
DENSITY OF CARGO 2.18 TONNE/ M3
VOLUME OF TANK 54 M3
WEIGHT OF TANK 14.8 TONNE
HYDRAULIC TEST PRESSURE 9.2 BAR
WELD TESTING DNV4.7.8, D102
MANUFACTURING PROCESS
VARIOUS PROCESS TO MANUFACTURING THE BULK STORAGE TANK ARE AS FOLLOWS
1. MEASUREMENT & MARKING / INSPECTION2. CUTTING3. ROLLING, ROLL BENDING4. SETTING / INSPECTIONS5. WELDING6. GRINDING7. TESTING OR INSPECTIONS8. ABRASIVE BLASTING9. PAINTING10. DISPATCHING
MEASUREMENT & MARKING/INSPECTION
MEASUREMENT
ACCORDING TO THE NAME, “MEASUREMENT” IS A PROCESS TO MEASURE ALL THE DIMENSIONS FOR A JOB. THE DIMENSIONS MAY BE LENGTH, HEIGHT, WIDTH, DIAMETER, THICKNESS, ETC. WITH THE HELP OF MEASURING TOOLS THE DIMENSIONS CAN BE ACCURATELY MEASURED THERE MAY BE VARIANCE IN DIMENSIONS AFTER MEASURING BUT IT SHOULD BE WITHIN TOLERABLE LIMITSPECIFIED BY THE CLIENT.
MEASURING TOOLS
1. TRY SQUIRE2. STEEL RULE3. BEVEL PROTECTOR4. SPRIT LEVEL INDICATOR5. TAPE
MARKING
EACH TANK AND PRESSURE VESSEL IS TO BE PERMANANTLY AND LEGIBLY MARKED ON BOILER OR BULK STORAGE TANK. MARKING IS A VERY IMPORTANT PROCESS AFTER MEASUREMENT. WITOUT MARKING WE CAN NOT GET ACCURATE DIMENSIONS TO MANUFACTURE A PRODUCT. MARKING CAN BE DONE BY DIFFERENT MARKING TOOLS.THE TOOLS MAY BE AS FOLLOWS
1. THREAD2. CHALK3. CENTRE PUNCH OR DOT PUNCH4. BALL PIN HAMMER
MARKING ON DIFFERENT SECTINOS
1. MARKING ON CARBON STEEL PLATE2. MARKING ON CARBON STEEL PIPES3. MARKING TO MAKE MANHOLES4. MARKING ON DISH5. MARKING ON LEADING PLATES
ACCORDING TO DRAWING EVERY PART IS MARKED BY THE MARKING TOOL.DRAWING & CARBON STEEL PLATE BOTH ARE PROVIDED BY COCHIN SHIPYARD LIMITED.
CUTTING CUTTING OPERATION IS VERY NECESSARY FOR MANUFACTURING A PRODUCT IN WORKSHOP.CUTTING IS THE PROCESS TO CUT THE MATERIAL INTO TWO OR MORE PARTS TO MAKE THE JOB OF REQUIRED SIZE.
CUTTING PROCESS:- THERE ARE ONLY TWO PROCESS TO CUT THE MATERIAL IN FEW.
1. GAS CUTTING2. SHEAR CUTTING
GAS CUTTING:- GAS CUTTING IS ALSO OF TWO TYPES
1. MANUALLY GAS CUTTING2. PUG OR AUTOMATED CUTTING.
MANUALLY GAS CUTTINGIN MANUAL CUTTING OPERATION THE OPERATOR SHOULD BE VERY CAREFUL TO CUT THE MATERIAL BECAUSE SMALL MISTAKES IN CUTTING CAN CHANGE THE ACCURACY OF A JOB.IN MANUAL GAS CUTTING OPERATION, HAND OF OPERATOR SHOULD NOT BE TRUMBLE. FLAME IS USED TO CUT THE METAL PLATE HENCE OPERATOR MUST WEAR THE APRON & GLOVES TO CUT THE METAL.
PUG OR AUTOMATED CUTTINGPUG CUTTING MACHINE IS A FULLY AUTOMATED MACHINE TO CUT THE MATERIALS OR CARBON STEEL PLATE VERY ACCURATELY.PUG CUTTING CAN BE PERFORMED IN ANY DIRECTION OR AT ANY ANGLE.CUTTING THICKNESS DEPENDS ONLY ON THE FLAME LENGTH.TO CUT THE METAL THE OXY-ACETYLENE CUTTING FLAME IS USED.THERE IS A PLATFORM TO MOVE THE PUG MACHINE.IT CAN BE STRAIGHT OR ROUND OR AT ANY ANGLE.
CUTTING GASESMETAL CUTTING GAS (LIQUIFIED PETROLEUM GAS), ACETYLENE AND OXYGEN, MIXTURE ARE USING TO CUT THE METALS.
SHEAR CUT MACHINESHEAR CUT MACHINE IS BASED ON HYDRAULIC PRINCIPLE.AN ELECTRIC MOTOR IS USED TO START THE MACHINE, AND AT THE TIME OF CUTTING A HYDRAULIC FORCE IS USED TO PUSH DOWN THE CUTTING TOOL TO CUT
THE METAL. SHEAR CUT MACHINE CAN CUT THE MATAL UPTO 12mm THICKNESS FOR CARBON STEEL PLATE AND 5mm FOR STAINLESS STEEL.
ROLL BENDING ROLLING PROCESS IS USED TO BEND THE PLATE TO REQUIRED DIAMETER. THE OPERATOR IS USING THE ROLL BENDING MACHINE TO BEND THE CARBON STEEL PLATE.
TYPES OF BENDING MACHINE THAT ARE USING IN FEW
1. ROLL BENDING MACHINE -12. ROLL BENDING MACHINE -23. ROLL BENDING MACHINE -3
R-1 MACHINE CAN ROLL UPTO MAXIMUM THICKNESS OF 20mm, 2.5met WIDTH & MINIMUM DIAMETER UPTO 420mm.R-2 MACHINE CAN ROLL UPTO MAXIMUM THICKNESS OF 40mm & 2.5met WIDTH.R-3 MACHINE CAN ROLL UPTO MAXIMUM THICHNESS OF 60mm & 2.5met WIDTH.
WORKING INSTRUCTION
CLEANINGTHE SLIDING PLANES HAVE TO BE CLEANED CAREFULLY. ALL PARTS COVERED WITH RUST PROTECTION COATING HAVE TO BE CLEANED WITH A SPECIAL SOLUTION.
SETTING & INSPECTIONSETTING IS ANOTHER A VERY IMPORTANT PROCESS.IT SHOUUD BE DONE VERY CAREFULLY.AS FOR WELDING PURPOSE THE ANGLE BETWEEN TWO CARBON STEEL PLATE SHOULD NOT MORE THAN 60 AND GAP SHOULD BE MINIMUM 3mm. OTHERWISEWELDING DEFECTS MAY BE OCCUR.AFTER SETTING INSPECTION SHOULD BE THERE TO MEASURE THE THICKNESS GAP AND ANGLE.
WELDING
WELDING IS VERY IMPORTANT PROCESS TO MANUFACTURE A PRODUCT.“WELDING IS THE METAL JOINING PROCESS WHEREIN LOCALIZED COALESCENE IS PRODUCED EITHER BY HEATING THE METAL TO SUITABLE TEMPERATURE WITH OR WITHOUT THE USE OF FILLER METAL”.
OR
“WELDING IS USED TO JOIN THE TWO METAL PLATE OF SAME & DIFFERENT SIZE WITH OR WITHOUT THE USE OF FILLER METAL”.
WELDING TYPES WHICH ARE USING IN FEW
1. SAW (SUBMERGED ARC WELDING)2. SMAW (SHIELDED METAL ARC WELDING)3. MIG OR GMAW (METAL INERT GAS WELDING)4. TIG OR GTAW (TUNGSTEN INERT GAS WELDING)
SAW WELDING
SAW WELDING IS A PROCESS TO JOIN THE METALS.IN ARC WELDING PROCESS THE SOURCE OF HEAT IS ELECTRICITY.IN ARC WELDING COALESCENE IS PRODUCED BY HEATING THE WORKPIECE WITH AN ELECTRIC ARC STRUCK BETWEEN AN ELECTRODE AND WORKPIECE. WELDING MAY BE CARRIED OUT IN AIR.THE TEMPERATURE OF MAY BE APPROXIMATELY 3300deg C.THE HEAT REQUIRED FOR JOINING THE METALS IS OBTAINED FROM AN ELECTRIC ARC.THE ELECTRIC MOTOR GENERATOR OR TRANSFORMER SETS ARE USED TO SUPPLY THE HIGH ELECTRIC CURRENT AND ELECTRODE ARE USED TO PRODUCE THE NECESSARY ARC.THE ELECTRODE SERVE AS THE FILLER ROD & ARC MELT THE SURFACE SO THAT THE METALS TO BE JOINED ARE FUSED TOGETHER.A HIGH CURRENT WITH A SMALLER ARC LENGTH PRODUCES A VERY INTENSE HEAT
FILLER METALIT IS THE MATERIAL THAT IS ADDED TO THE WELD POOL TO ASSIST IN FILLING THE GAP. THE FILLER METAL IS USUALLY AVAILABLE IN ROD FORM. FILLER ROD FORMS AN INTEGRAL PART OF THE WELD.
FILLER ROD MATERIAL
FILLER ROD CAN BE MADE OF CARBON STEEL.
FLUX AT THE TIME OF WELDING IF THE METAL IS HEATED IN AIR, OXYGEN IN AIR COMBINE WITH THE METAL TO FORM OXIDES WHICH RESULT IN POOR QUALITY, LOW STRENGTH WELD.IN THESE CASES WELDING IS IMPOSSIBLE .TO AVOID THIS PROBLEM A FLUX IS ADDED DURING WELDING. THIS FLUX PREVENTS OXIDATION BY PREVENTIG OXYGEN FROM CONTACTING THE WELD ZONE.
FLUX MATERIALS TO PROTECT OXIDATION PROCESS WE USE FLUX. THE FLUX MAY BE BORIC ACID, SODA ASH, & SODIUM CHLORIDE ETC.
ELECTRODE FILLER ROD USED IN SUBMERGED ARC WELDING & METAL INERT GAS WELDING IS CALLED AS ELECTRODE. THE ELECTRODE ARE MADE OF METTALIC WIRES. IT IS COATED UNIFORMLY WITH A PROTECTIVE COATING FLUX.THE SIZE OR DIAMETER OF METTALIC WIRE WILL DEPEND UPON AMOUNT OF WELD.METAL TO BE DEPOSITED ON THE TYPE OF JOINT.“IN FEW, AHEAVY COATED IRON POWDER LOW HYDROGEN TYPE ELECTRODE IS USING TO FILL THE GAP.
ELECTRODE HOLDER IT IS A DEVICE USED FOR MECHANICALLY HOLDING THE ELECTRODE AND CONDUCTING CURRENT TO IT.
SMAW (SHIELDED METAL ARC WELDING)
SHIELDED METAL ARC WELDING IS ALSO KNOWN AS MANUAL METAL ARC WELDING MANUAL ARC WELDING PROCESS USES A CONSUMABLE
ELECTRODE COATED IN FLUX TO LAY THE WELD.AN ELECTRIC CURRENT IN THE FORM EITHER AC OR DC FROM A WELDING POWER SUPPLY UNIT IS USED TO FORM AN ELECTRIC ARC BETWEEN THE ELECTRODE AND METALS TO BE JOINED.AS THE WELD IS LAID, FLUX COATING OF ELECTRODE DISINTEGRATE, GIVING OFF VAPOURS THAT SERVE AS A SHIELDING GAS AND PROVIDE A LAYER OF SLAG,BOTH OF WHICH PROTECTTHE WELD AREA FROM ATMOSPHERIC CONTAMINATION. SMAW IS USED EXTENSIVELY IN CONSTRUCTION OF STEEL STRUCTURE & IN INDUSTRIAL FABRICATION.
OPERATION TO STRIKE THE ARC, THE ELECTRODE IS BROUGHT INTO CONTACT WITH THE WORKPIECE IN A SHORT SWEEPING MOTION AND THEN PULLED AWAY SLIGHTLY, WITH A MOVEMENT LIKE LIGHTING A MATCH. THIS INITIATE THE ARC, MELTING OF WORKPIECE AND CONSUMABLE ELECTRODE, AND CAUSE DROPLET OF ELECTRODE TO BE PASSED FROM THE ELECTRODE TO THE WELD POOL, AS THE ELECTRODE MELTS THE FLUX COVERING DISINTEGRATE, GIVING OF VAPOURS THAT PROTECT THE WELD AREA FROM OXYGEN AND OTHER ATMOSPHERIC GASES. INADDITION, THE FLUX PROVIDE MOLTEN SLAG WHICH COVERS THE FILLER METAL AS IT TRAVEL FROM THE ELECTRODE TO THE WELD POOL.ONCE PART OF WELD POOL, THE SLAG FLOATS TO THE SURFACE AND PROTECT THE WELD FROM CONTAMINATION AS IT SOLIDIFIES.ONCE HARDENED IT MUST BE CHIPPED AWAY TO REVEAL THE FINISHED WELD. THE ACTUAL WELDING TECHNIQUE UTILIZED DEPENDS UPON THE ELECTRODE, THE COMPOSITION OF WORKPIECE & POSITION OF JOINT WORKPIECE & ALSO WELDING SPEED.
APPLICATION AND MATERIAL SMAW IS ONE OF THE MOST POPULAR WELDING PROCESS.IT IS PARTICULARLY DOMINANT IN MAINTENANCE AND REPAIR INDUSTRYAND IS HEAVILY USED IN CONSTRUCTION OF STEEL STRUCTURE AND IN INDUSTRIAL FABRICATION. SMAW IS OFTEN USED TO WELD CARBON STEEL, LOW AND HIGH ALLOYS STEEL, STAINLESS STEEL, CAST IRON ETC.
EQUIPMENTSMAW WELDING EQUIPMENT TYPICALLY CONSISTS OF A CONSTANT CURRENT WELDING POWER SUPPLY AND ELECTRODE WITH A N ELECTRODE HOLDER, A GROUND CLAMP ZND WELDING CABLES CONNECTING INTO THE TWO.IT CAN BE OPERATEWITH THE HELP OF AC & DC CURRENT.
ELECTRODE THE CHOICE OF ELECTRODE DEPENDS ON A NUMBER OF FACTORS, INCLUDING THE MATERIALS.WELDING POSITION AND DESIRED WELD PROPERTIES.TO IDENTIFY ELECTRODE THE AWS ESTABLISHED A SYSTEM THAT ASSIGN ELECTRODE WITH A FOUR OR FIVE DIGIT NUMBER. COVERED ELECTRODE MADE OF MILD OR LOW ALLOY STEEL CARRY THE PREFIX E, FOLLOWED BY THEIR NUMBER .THE FIRST TWO OR THREE DIGIT NUMBER SPECIFIES THE TENSILE STRENGTH OF WELD. IN FEW WE ARE USING ONLY E7018 CARBON STEEL ELECTRODE.
QUALITY THE MOST COMMON QUALITY PROBLEM ASSOCIATED WITH SMAW INCLUDING WELD SPATTER, POROSITY, POOR FUSION, SHALLOW PENETRATION, AND CRACKING.WELD SPATTER WHEN NOT AFFECTING THE INTEGRITY OF WELD, DAMAGE ITS APPEARANCE AND INCREASE CLEANING COST.
METAL INERT GAS WELDING OR GMAW
METAL INERT GAS WELDING, SOMETIMES REFFERED TO BY ITS SUBTYPES GAS METAL ARC WELDING OR METAL ACTIVE GAS WELDING IS A SEMI-AUTOMATIC OR AUTOMATIC ARC WELDING PROCESS IN WHICH ACONTINUOUS AND CONSUMABLE WIRE ELECTRODE AAND A SHIELDING GAS ARE FED THROUGH A WELDING GUN.A CONSTANT VOLTAGE DIRECT CURRENT POWER SOURCE IS MOST COMMONLY USED WITH MIG.ALTERNATIVE CURRENT CAN ALSO BE USED WITH MIG.
EQUIPMENT TO PERFORM MIG THE BESIC NECESSARY EQUIPMENT ISA WELDING GUN, A WIRE FEED UNIT, A WELDING POWER SUPPLY, AN ELECTRODE WIRE, & SHIELDED GAS SUPPLY.
WELDING GUN AND WIRE FEED UNITA TYPICAL MIG WELDING GUN HAS A NUMBER PARTS, A CONTROL SWITCH, A ONTACT TIP, A POWER CABLE, A GAS NOZZLE AND A GAS HOSE THE CONTROL SWITCH WHEN PRESSED BY THE OPERATOR, INITIATE THE WIRE FEED, ELECTRIC POWER, AND THE SHIELDED GAS FLOW, CAUSING AN ELECTRIC ARC TO BE STRUCK.THE CONTACT TIP NORMALLY MADE OF COPPER & SOMETIMES CHEMICALLY TREATED TO REDUCE WELD SPATTER.THE WIRE FEED UNIT SUPPLIES THE ELECTRODE TO WORK TO WORK DRIVING IT THROUGH CONDUITS AND ON CONTACT TIP.MOST MODEL PROVIDES THE WIRE AT ACONSTANT FEED RATE.
POWER SUPPLYMOST APPLICATION OF MIG USE A CONSTANT VOLTAGE SUPPLY. AS A RESULT ANY CHANGE IN ARC LENGTH RESULTS IN A LARGE CHANGE IN HEAT INPUT AND CURRENT.AC CURRENT IS RARELY USED WITH MIG, DIRECT CURRENT IS EMPLOYED.
ELECTRODE ELECTRODE SELECTION IS BASED PRIMARILYON COMPOSITION OF METAL BEING WELDED BUT ALSOON THE PROCESS VARIATION BEING USED, THE JOINT DESIGN, MATERIAL SURFACE CONDITION.THE CHOICE OF ELECTRODE MSTRONGLY INFLUENCE THE MECHANICAL PROPERTIES OF WELD AREA, AND IS A KEY FACTOR IN WELD QUALITY.IN GENERAL, THE FINISHED WELD METAL SHOOLD HAVE MECHANICAL PROPERTY SIMILAR TO THOSE OF BASE METAL.IN FEW CARBON STEEL ELECTRODE IS BASICALLY USING.ALL COMMERCIAL ELECTRODE CONTAIN DEOXIDIDING METALS SUCH AS SILICON,MANGNESE, TITANIUM ETCIN SMALL PERCENTAGE TO HELP PREVENT OXYGEN POROSITY & OTHER DEFECTS.
SHIELDING GAS SHIELDING GASES ARE NECESSARY FOR METAL INERT GAS WELDING TO PROTECT THE WELD AREA FROM ATMOSPHERIC GASES SUCH AS OXYGEN, NITROGEN WHICH CAN CAUSE FUION DEFECTS, POROSITY IF THEY COME IN CONTACT WITH ELECTRODE, THE ARC OR WELDING METAL.THIS PROBLEM IS COMMON TO ALL ARC WELDING PROCESS, BUT INSTEAD OF
SHIELDING GAS, MANY ARC WELDING METHODS USING A FLUX MATERIAL WHICH DISINTEGRATE INTO PROTECTIVE GAS WHEN HEATED TO WELDING TEMPERATURE.IN MIG THE ELECTRODE WIRE DOES NOT HAVE ANY FLUX COATING & ASEPERATE SHIELDING GAS IS EMPLOYED TO PROTECT THE WELD. THIS ELIMINATE SLAG, THE HARD RESIDUE FROM FLUX THAT BUILT UP AFTER WELDING AND MUST BE CHIPPING OFF TO REVEAL THE COMPLETED WELD.GENERALLY IN SHORT CIRCUIT MIG, HIGHER CARBON DIOXIDE INCREASE THE WELD HEAT AND ENERGY WHEN ALL OTHER PARAMETERS ARE HELD THE SAME.
OPERATION IN MOST APPLICATION, GAS METAL ARC WELDING IS A FAIRLY SIMPLE WELDING PROCESS TO LEARN. THE BASIC TECHNIQUE FOR MIG IS QUITE SIMPLE, SINCE THE ELECTRODE IS FED AUTOMATICALLY THROUGH THE TORCH MIG REQUIRES ONLY THAT THE OPERATOR GUIDE THE WELDING GUN WITH PROPER POSITION AND ORIENTATION ALONG THE AREA BEING WELDED. KEEPING A CONSISTENT CONTACT TIP TO WORK DISTANCE IS IMPORTANT, BECAUSE A LONG STICKOUT DISTANCE CAN CAUSE THE ELECTRODE TO OVERHEAT AND WILL ALSO WASTE SHIELDING GAS.STICKOUT DISTANCE VARIES FOR DIFFERENT MIG WELD PROCESS AND APPLICATION. FOR SHORT CIRCUITING TRANSFER THE STICKOUT IS GENERALLY 1/4 TO ½ inch.
QUALITY TWO OF THE MOST PREVELENT QUALITY PROBLEMS IN MIG WELDING ARE DROSS AND POROSITY. IN MIG THE PRIMARY CAUSE OF POROSITY IS GAS ENTRPMENT IN WELDING POOL, WHICH OCCURS WHEN THE METAL SOLIDIFIES BEFORE GAS ESCAPES.THE GAS CAN COME FROM IMPURITIES IN THE SHIELDING GAS OR ON WORKPIECEAS WELL AS FROM AN EXCESSIVELY LONG OR VIOLENT ARC.GENERALLY THE AMOUNT OF GAS ENTARPPED IS DIRECTLY RELATED TO THE COOLING RATE OF THE WELD POOL. TO REDUCE IT THE ELECTRODE AND WORKPIECE SHOULD BE CLEAN.
TUNGSTEN INERT GAS WELDING OR GTAW
GAS TUNGSTEN INERT GAS SHIELDED ARC WELDING IS AN ARC WELDING PROCESS WHICH EMPLOYS AN INERT GAS TO PROTECT THE WELD FROM ATMOSPHERE. IN THIS PROCESS HEAT IS SUPPLIED BY AN ARC STRUCK BETWEEN A TUNGSTEN ELECTRODE AND THE BASE METAL. A SEPARATE FILLER ROD IS USED TO FILL UP THE GROOVES.IN TUNGSTEN ARC WELDING, THE WELDER MUST HANDLE A WELDING TORCH IN ONE HAND AND A SEPARATE FILLER WIRE IN OTHER HAND.
INERT GAS CYLINDER WITH REGULATOR AN INERT GAS CYLINDER IS USED TO SUPPLY INERT GAS TO PROTECT THE MOLTEN METAL FROM ATMOSPHERIC CONTAMINATIONS, AND REGULATOR IS USED TO REGULATE THE PRESSURE AND FLOW OF THE INERT GAS SUPPLY.
INERT GAS IN TUNGSTEN INERT GAS WELDING PROCESS THE ARGON OR HELIUM CAN BE USED FRQUENTLY BUT IN FEW THE ARGON GAS IS USING.
WELDING TORCH A WELDING TORCH HAS AN ELECTRODE HOLDING DEVICE, GAS FLOW PASSAGE AND ETC.
WATER SUPPLY UNIT THIS UNIT SUPPLY WATER TO TORCH THROUGH HOSE FOR COOLING TORCH.THE HOSE CARRY THE WATER FROM WATER UNIT.
ELECTRODE THE ELECTRODE IS USED TO PRODUCE THE ARC .FOR GOOD WELDING THE SHAPE OF TIP MUST BE IN CORRECT POSITION. ELECTRODE IS USUALLY MADE OF TUNGSTEN IN TIG WELDING BUT CARBON STEEL ELECTRODE CAN ALSO BE USED.
OPERATION INITIALLY, OPERATOR PREPARE THE MATERIAL AS PER DRAWING. THEN WELDER KEEP THE WELDING TORCH NEAR THE WELD STARTED POINT, INITIATE THE ARC WITHOUT TOUCHING THE ELECTRODE BY PRESSING THE BUTTON ON TORCH, THE METAL ELECTRODE IS FUSED INTO THE GROOVE. AND WELDING PROCESS IS COMPLETE. ARGON GAS IS USED TO PROTECT THE WELDED AREA FROM ATMOSPHERIC CONTAMINATION LIKE OXYGEN & NITROGEN ETC.
APPLICATION
1. HIGH WELDING SPEED2. HIGH METAL DEPOSITION RATE3. DEEP PENETRATION4. NO SLAG FORMATION, LESS HEAT AFFECTED ZONE.
TYPES OF JOINT
1. SINGLE BUTT V-TYPE JOINT2. DOUBLE BUTT V-TYPE JOINT3. T-TYPE JOINT
SEQUENCE OF OPERATION
1. EDGE PREPARATION2. TACKING3. WELDING4. COOLING5. CHIPPING6. CLEANING
TOOL REQUIRED
1. POWER SUPPLY2. WELDING TORCH3. ELECTRODE4. CHIPPING HAMMER5. WIRE BRUSH6. GLOVES7. APRON8. SAFETY GOGGLES9. SHIELD
GRINDING
AFTER COMPLETING WELDING PROCESS, THE NEED OF SURFACE FINISH IS OCCURS. TO REMOVE THE EXCESS METAL FROM THE SURFACE GRINDING PROCESS IS STARTED.GRINDING IS A FINISHING PROCESS USED TO IMPROVE SURFACE FINISH. IN GRINDING, AN ABRASIVE MATERIAL RUBS AGAINST METAL PART & REMOVE THE SLAG OR IMPURITY OF MATERIAL.THE ABRASIVE MATERIAL IS TYPICALLY ON SURFACE OF WHEEL.ABRASIVE ACTION OF GRINDING GENERATE EXCESSIVE HEAT SO THAT FLOODING OF MATERIAL WITH FLUID IS NECESSARY.
REASONS FOR GRINDING
1. THE MATERIAL IS TOO HARD TO BE MACHINNED ECONOMICALLY2. TOLERANCE REQUIRED PRECLUDE MACHINING
3. MACHINING REMOVES EXCESSIVE MATERIAL
GRINDING TOOLS MATERIALS
GRINDING TOOL MATERIALS ARE BASICALLY MADE OF SILICA.SILICON DIOXIDE, ALUMINIUM TRIOXIDE. SAND ETC.
SPECIFICATION OF TOOLS
1. GEMINI D3MC
MAXIMUM RPM 8500
SIZE 180 * 7 * 22.23 (ALL DIMENSIONS ARE IN MM)
180mm-OUTER DIAMETER 7mm-THICKNESS 22.23mm-INNER DIAMETER
2. CARBORUNDUM
MAXIMUM RPM 8730
SIZE 180 * 3 * 22.23 (ALL DIMENSIONS ARE IN MM)
180mm-OUTER DIAMETER 3mm- THICKNESS 22.23mm-INNER DIAMETER
3. GEMINI
MAXIMUM RPM 9200
SIZE 100 * 20 * 12.70 (ALL DIMENSIONS ARE IN MM)
100mm-OUTER DIAMETER 20mm- THICKNESS 12.70-INNER DIAMETER
GRADE OF TOOLS A16S3BL4
TESTING / INSPECTION
AFTER COMPLETION OF ALL NECESSARY MANUFACTURING PROCESS, INSPECTION PROCESS IS VERY URGENT FOR SUITABILITY OF A JOB. INSPECTION PROCESS IS USED TO FIND OUT THE DEFECT IN THE JOB LIKE CRACKS, GAP, POROSITY, GAP ETC.
INSPECTION TECHNIQUES
1. VISUAL INSPECTION2. ULTRASONIC TESTING3. DYE PENETRANT TESTING4. MAGNETIC PARTICLE INSPECTION5. HYDRAULIC TESTING6. X-RAYS RADIOGRAPHY
VISUAL INSPECTIONS
IT IS A DESTRUCTIVE TESTING WHICH IS USED TO FIND OUT THE SURFACE AND SUB SURFACE DEFECT.THIS FUNCTION SIMPLY PERFORMED BY THE HELP OF TORCH .SUN LIGHT IS NOT SUFFICIENT TO SEE SMALL HOLES CRACKS AND GAP ON SURFACE SO SOME EXTRA LIGHT IS VERY NECESSARY TO FIND OUT THE SURFACE DEFECT. IF SOME SURFACE DEFECT ARE FIND OUT BY VISUAL INSPECTION THEN THAT PORTION AGAIN GRINDED OR WELDED AND SURFACE DEFECTS IS REMOVED.
ADVANTAGE
1. VISUAL INSPECTION IS VERY EASY PROCESS TO PERFORM.IT CAN BE DONE SIMPLY WITH THE HELP OF A TORCH.
2. NOT MORE SKILL IS REQUIRED TO PERFORM THIS FUNCTION.
DISADVANTAGE
1. ALL DEFECT CAN NOT SEEN BY THE HELP OF EYES.2. INTERNAL DEFECTS ARE NOT DETECTS BY VISUAL INSPECTIONS
ULTRASONIC TESTING
ULTRASONIC INSPECTIONS PROCESS ARE NON-DESTRUCTIVE METHODS FOR THE DETECTION OF SUB SURFACE DEFECTS OR INNER DEFECTS IN FERROUS MATERIALS.NON DESTRUCTIVE TESTING IN GREAT VARIETY ARE IN WORLDWIDE USE TO DETECT VARIATION IN STRUCTURE, MINUTE CHANGES IN SURFACE FINISH, THE PRESENCE OF CRACKS OR OTHER PHYSICAL DISCONTINUITIES, TO MEASURE THE THICKNESS OF MATERIAL AND COATING.ULTRASONIC TECHNIQUE BASICALLY A MECHANICAL PHENOMENA THESE ARE PARTICULARLY ADAPTABLE TO DETERMINATION OF STRUCTURAL INTEGRITY OF ENGINEERING MATERIALS.
MOST APPLICATION OF ULTRASONIC TESTING ARE AS FOLLOWS
1. FLAW DETECTION2. THICHNESS MEASUREMENT3. STUDY OF MATTALURGICAL STRUCTURE
ULTRASONIC TESTING IS OFTEN PERFORMED ON STEEL AND OTHER METALS AND ALLOYS, THOUGH IT CAN ALSO BE PERFORMED ON CONCRETE, WOOD AND COMPOSITE.IT IS A FORM OF NON-DESTRUCTIVE TESTING USED IN MANY INDUSTRIES INCLUDING AEROSPACE, AUTOMOTIVE AND OTHER TRANSPORTATION SECTOR.
OPERATION
IN ULTRASONIC TESTING AN ULTRASOUND ETRANSDUCER CONNECTED TO DIAGNOSTIC MACHINE IS PASSED OVER THE OBJECT BEING INSPECTED.THE TRANSDUCER IS TYPICALLY SEPARATED FROM THE TEST OBJECT BY A COUPLANT OR BY WATER.THERE ARE TWO METHODS OF RECEIVING THE ULTRASOUND WAVEFORM, REFLECTION AND ATTENUATION.IN REFLECTION MODE, THE TRANSDUCER PERFORM BOTH THE SENDING AND RECEIVING OF PULSE WAVE AS THE SOUND IS REFLECTED BACK TO THE DEVICE.REFLECTED ULTRASOUND COMES FROM AN INTERFACE, SUCH AS BACK WALL OF THE OBJECT OR FROM AN IMPERFECTION WITHIN AN OBJECT. THE DIAGNOSTIC MACHINE DISPLAYS THESE RESULTS IN THE FORM OF A SIGNAL WITH AN AMPLITUDE REPRESENTING THE INTENSITY OF THE REFLECTION AND THE DISTANCE, REPRESENTING THE ARRIVAL TIME OF REFLECTION.IN
ATTENUATION MODE, A TRANSMITTER SENDS ULTRASOUND THROUGH ONE SURFACE, AND A SEPARATE RECEIVER DETECT THE AMOUNT THAT HAS REACHED IT ON ANOTHER SURFACE AFTER TRAVELING THROUGH A MEDIUM.IMPERFECTION OR OTHER CONDITION IN THE SPACE BETWEEN THE TRANSMITTER AND RECEIVER REDUCE THE AMOUNT OF SOUND TRANSMITTED ,THUS REVEALING THEIR PRESENCE.ULTRASONIC FLAW DETECTOR IS USING TO FIND OUT THE IMPERFECTIONS IN FERROUS MATERIALS.
ADVANTAGE
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. NONHAZARDOUS TO OPERATIONS.5. CAPABLE OF PORTABLE OR HIGHLY AUTOMATED OPERATION.6. GREATER ACCURACY THAN OTHER NONDESTRUCTIVE METHODS IN
DETERMINING THE DEPTH OF INTERNAL FLAWS AND THICKNESS OF PARTS WITH PARALLEL SURFACE.
DISADVANTAGE
1. MANUAL OPERATION REQUIRES CAREFUL ATTENTION BY EXPERIENCE TECHNICIANS.
2. PARTS THAT ARE ROUGH, IREGULAR IN SHAPE, VERY SMALL OR THIN OR NOT HOMOGENEOUS ARE DIFFICULT TO INSPECT.
DYE PENETRANT TESTING
LIQUID OR DYEPENETRANT TESTING IS ONE OF THE OLDEST METHOD OF NON-DESTRUCTIVE TESTING.IT IS BASED ON OLD OIL & WHITING PROCESS.
OPERATION
PENETRANT INSPECTION IS VERY IMPORTANT PROCESS FOR FERROUS ALLOYS.IN THIS FIRST A LIQUID PENETRANT IS APPLIED TO THE SURFACE OF A PART .IT IS PERMITTED TO REMAIN ON THE SURFACE FOR A PERIOD OF TIME.DURING WHICH IT PENETRATE INTO ANY DEFECT OPEN AT THE SURFACE. AFTER THE PENETRATING PERIOD, THE EXCESS PENETRANT THAT REMAINS ON SURFACE IS REMOVED, THEN AN ABSORBENT, LIGHT
COLOURED POWDER MATERIAL CALLED A DEVELOPER IS APPLIED TO THE SURFACE.THIS DEVELOPER ACT AS A BLOTTER & DRAW OUT A PORTION OF THE PENETRANT WHICH HAD PREVIOUSLY SEEPED INTO THE SURFACE OPENING.AS THE PENETRANT IS DRAWN OUT, IT DIFFUSES INTO THE COATING OF DEVELOPER FORMING INDICATION THAT ARE MUCH WIDER THAN THE SURFACE OPENING WITH WHITCH THEY ARE ASSOCIATED.THEN WE SEE THE PART AND LOOKS FOR THESE COLOURED INDICATIONS AGAINST THE BACKGROUND OF THE DEVELOPING POWDER..THIS METHOD IS ONLY USED TO FIND OUT THE SURFACE DEFECTS OF MATERIALS.
TO FIND OUT THE DEFECTS, ALL PARTS MUST BE CLEAN AND DRY BEFORE A DYE PENETRANT IS APPLIED. MATERIAL MUST BE FREE OF RUST, SCALE AND WELDING FLUX, SPATTER GREASE, PAINT ETC. ANY OF THESE CONTAMINANT CAN PREVENT PENETRANT FROM ENTERING DEFECT.
PENETRATION TIME
PENETRATION TIME DEPENDS UPON FOLLOWINGS
1. TYPE OF PENETRANT USED2. TYPE OF MATERIAL TO BE INSPECTED3. SENSITIVITY DESIRED4. TYPE OF DEFECTS TO BE FOUND
MAGNETIC PARTICLE INSPECTIONS
MAGNETIC PARTICLE INSPECTIONS PROCESS IS NON-DESTRUCTIVE METHODS FOR THE DETECTION OF SURFACE DEFECT IN FERROUS MATERIALS. THEY MAKE USE OF EXTERNALLY APPLIED MAGNETIC FIELD OR ELECTRIC CURRENT THROUGH THE MATERIAL AND THE PRINCIPLE THAT THE MAGNETIC FLUX WILL LEAVE THE PARTAT THE AREA OF FLAW.THE PRESENCE OF SURFACE OR NEAR SURFACE FLAW IN THE MATERIAL CAUSES LEAKAGE OF MAGNETIC FIELD AT THE FLAW.THIS DEFORMATION OF MAGNETIC FIELD IS NOT LIMITED TO THE IMMEDIATE LOCALITY OF THE DEFECT BUT EXTEND FOR A CONSIDERABLE DISTANCE, EVEN THOUGH THE SURFACE AND INTO THE AIR IF THE MAGNETISM IS INTENSE ENOUGH.THUS THE SIZE OF DISTORTION IS MUCH LARGER THAN THAT OF DEFECT AND IS MADE VISIBLE AT THE SURFACE OF PART BY MEANS OF TINY PARTICLE THAT ARE ATTRACTED TO THE LEAKAGE FIELDS.
THE MOST COMMON METHOD OF MAGNETIC PARTICLE INSPECTION USES FINELY DIVIDED IRON OR MAGNETIC IRON OXIDE, HELD IN SUSPENSION IN A SUITABLE LIQUID. THIS IS REFFER TO CARRIER .THE PARTICLE OFTEN COLOURED AND USUALLY COATED WITH FLUORESCENT DYES THET ARE
MADE VISIBLE WITH A HAND HELD ULTRAVIOLET LIGHT. THE SUSPENSION IS SPRAYED OR PAINTED OVER MAGNETIZED SPECIMEN DURING MAGNETIZATION WITH A DIRECT CURRENT TO LOCALIZE AREAS WHERE MAGNETIC FIELD HAS PROTRUDED FROM SURFACE .THE MAGNETIC PARTICLES ARE ATTRACTED BY THE SURFACE FIELD IN THE AREA OF DEFECT AND HOLD ON TO THE EDGE OF DEFECTS TO REVEAL IT AS A BUILT UP OF PARTICLES.
IT IS COMMONLY USED FOR INSPECTING STRUCTURAL PARTS THAT HAVE BEEN IN SERVICE FOR SOMETIME TO FIND FATIGUE CRACKS.IT IS QUITE ECONOMIC NON-DESTRUCTIVE TEST BECAUSE IT IS EASY TO DO AND MUCH FASTER THAN ULTRASONIC AND RADIOGRAPHIC TESTING.MAGNETIC PARTICLE MAY NOT BE USED FOR NON-FERROUS MATERIALS AND NON-MAGNETIC FERROUS MATERIALS SUCH AS AUSTENITIC STAINLESS STEEL.IN SUCH CASES OTHER METHODS SUCH AS DYE PENETRANT INSPECTION ARE USED.
HYDRAULIC TESTING
A HYDROSTATIC TEST IS THE COMMON WAY IN WHICH LEAKS CAN BE FOUND IN PRESSURE VESSEL BULK STORAGE TANKS OR IN PILE LINES.HYDROSTATIC TESTING IS ALSO A WAY IN WHICH A GAS PRESSURE VESSEL SUCH AS GAS CYLINDER OR A BOILER IS CHECKED FOR LEAK OR FLAWS.TESTING IS VERY NECESSARY BECAUSE SUCH CONTAINERS CAN EXPLODE IF THEY FAIL WHEN CONTAINING CMPRESSED GAS OR LIQUID.
HYDRAULIC TEST ARE CONDUCTED UNDER CONSTRINTS OF EITHER THE INDUSTRY,S OR THE CUSTOMER,S SPECIFICATIONS.THE VESSEL IS FILLED WITH A NEARLY INCOMPRESSIBLE LIQUID USUALLY WATER AND EXAMINED FOR LEAKS OR PERMANENT CHANGE IN SHAPE.RED OR FLUORESCENT DYES ARE USUALLY ADDED TO WATER TO LEAKS EASIER TO SEE.THE TEST PRESSURE IS ALWAYS CONSIDERABLY MORE THAN THE OPERATING PRESSURE TO GIVE AMARGIN FOR SAFETYTYPICALLY 1.3 TIMES OF DESIGN PRESSURE.WATER IS COMMONLY USED BECAUSE IT IS ALMOST INCOMPRESSIBLE ( COMPRESSIBLE ONLY FOR WEIGHT NOT AIR PRESSURE )., SO WILL ONLY EXPAND BY A VERY SMALL AMOUNT SHOULD THE VESSEL SPLIT.
IN FEW THIS TEST IS PERFORMED ON BULK STORAGE TANKS AND PIPE LINES.TO PERFORM THIS OPERATION, FIRST WITH THE HELP OF WATER PUMP, WATER FILLS INSIDE THE TANK OR PIPE LINES & A PRESSURE GAUGE IS USED TO MEASURE THE INSIDE PRESSURE.AFTER FILING THE TANKS WITH WATER, WE SET THE PRESSURE 1.3 TIMES OF DESIGN PRESSURE & LEAVE THIS PROCESS FOR HALF HOUR OR FOR ONE HOURS. IF
AFTER SOME TIME THE PRESURE DECREASE LESS THE REQUIRED PRESSURE THEN WE CAN EASILY FIND OUT THAT THERE IS A LEAKAGE DEFECT IN THE TANKS OR I PIPE LINES.TO FIND OUT THAT WE USE RED OR FLUORESCENT DYES TO MAKE LEAKS EASIER TOO SEE.
X-RAYS RADIOGRAPHY
X-RAYS RADIOGRAPHY IS A FORM OF NON-DESTRUCTIVE TETING.THIS INSPECTION PLAY A VERY IMPORTANT ROLE TO FIND OUT THE INTERNAL IMPERFECTIONS IN THE TANKS.
REQUIREMENTS & COMPLIANCE FOR A WRITTEN PROCEDURE A WRITTEN PROCEDURE SHALL CONNTAIN AS MINIMUM THE FOLLOWING VARIABLES
1. MATERIAL AND THICKNESS RANGE2. ISOTOPES USED OR MAXIMUM X-RAYS VOLTAGE3. MAXIMUM SOURCE SIZE4. FILM BRAND AND DESIGNATION5. SCREEN USED
SURFACE PREPARATION
MATERIALS SURFACE SHALL SATISFY THE REQUIREMENT OF APPLICABLE MATERIALS SPECIFICATIONS. BY ANY SUITABLE PROCESS TO A DEGREE THAT SURFACE IRREGULARITIES CAN NOT BE CONFUSED WITH IRREGULARITIES.
WELDS THE WELD SURFACE IRREGULARITIES ON BOTH THE INSIDE AND OUTSIDE SHALL BE REMOVED BY ANY SUITABLE PROCESS TO SUCH A DEGREE THAT THE RESULTING RADIOGRAPHIC IMAGE DUE TO ANY IRREGULARITIES CAN NOTBE CONFUSED WITH THE IMAGE OF ANY DISCONTINUITY.
SURFACE FINISH THE FINISHED SURFACE OF ALL BUTT WELDED JOINTS MAY BE FLUSH WITH THE BASE MATERIAL.SURFACE SHOULD BE CLEAN FOR RADIOGRAPHY TESTING.
RADIOGRAPHY TECHNIQUES
1. SINGLE WALL SINGLE IMAGE2. DOUBLE WALL SINGLE IMAGE3. DOUBLE WALL DOUBLE IMAGE
X-RAYS MACHINE CAN PENETRATE THE WAL UP TO 12mm THICKNESS.FOR X-RAY RADIOGRAPHY WE USE ISOTOPES SUCH AS IRIDIUM-192, COBALT-60. ISOTOPE IRIDIUM –192 CAN PENETRATE UPTO 40mm THK, AND COBALT-60 CAN PENETRATE UPTO MORE THAN 40mm.SOURCE FILM DISTANCE IS 16 INCH.
SINGLE WALL SINGLE IMAGE TECHNIQUE
A SINGLE WALL EXPOSURE TECHNIQUE SHALL BE USED FOR RADIGRAPHY WHENEVER PRACTICAL.WHEN IT IS NOT PRACTICAL TO USED A SINGLE WALL TECHNIQUE A DOUBLE TECHNIQUE SHALL BE USED.A ADEQUATE NO. OF EXPOSURE SHALL BE MADE TO DEMONSTRATE THAT THE REQUIRED COVERAGE HAS BEEN OBTAINED.
IN SINGLE WALL TECHNIQUE THE RADIATION PASSES THROUGH ONLY ONE WALL OF THE WELD (MATERIAL) WHICH REQUIRED FOR ACCEPTANCE ON RADIOGRAPH.
DOUBLE WALL TECHNIQUE
WHEN IT IS NOT PRACTICABLE TO USE SINGLE WALL TECHNIQUE ON THE FOLLOWING DOUBLE WALL TECHNIQUE SHALL BE USED.
1. SINGLE WALL VIEWING
FOR MATERIAL AND FOR WELD IN COMPONENT A TECHNIQUE MAY BE USED IN WHICH RADIATION PASSES THROUGH TWO WALLS AND ONLY THE WELD (MATERIAL) ON THE FILM SIDE WALL IS VIEWED FOR ACCEPTANCE ON THE RADIOGRAPH.WHEN COMPLETE COVERAGE IS REQUIRED FOR CIRCUMFERENCIAL WELD (MATERIAL) A MINIMUM OF THREE EXPOSURE TAKEN 120 DEGREE TO EACH OTHER SHALL BE MADE.
2. DOUBLE WALL VIEWING
FOR MATERIAL AND FOR WELD IN COMPONENT 3.5 OR LESS IN NOMIAL OUTSIDE DIAMETER, A TECHNIQUE MAY BE USED IN WHICH RADIATION PASSES THROUGH TWO WALLS AND THE WELD9MATERIAL) IN BOTH WALL IS VIEWED FOR ACCEPTANCE ON SOME RADIOGRAPH.FOR DOUBLE
WALL VIEWING ONLY A SOURCE SIDE PENETRAMETER SHALL BE USED.CARE SHOULD BE EXERCISED TO ENSURE THE REQUIRED GEOMETRIC UNSHARPNESS IS NOT EXCEEDED.IF GEOMETRIC UNSHARPNESS REQUIREMENT CAN NOT BE MET THAN THE SINGLE WALL VIEWING IS USED
1. FOR WELD, THE RADIATION BEAM MAY BE OFFSET FROM THE PLANE OF WELD AT AN ANGLE SUFFICIENT TO SEPARATE THE IMAGE OF SOURCE SIDE AND FILM SIDE PORTION OF WELD SO THAT THERE IS NO OVERLAP OF AREASTO BE INTERPRETED.WHEN COMPLETE COVERAGE IS REQUIRED A MINIMUM OF TWO EXPOSURES TAKEN A 90deg TO EACH OTHER SHALL BE M ADE FOR EACH JOINT.
2. AS AN ALTERNATIVES THE WELD MAY BE RADIGRAPHED WITH THE RADIATION BEAM POSITIONED SO THAT THE IMAGE OF BOTH WALL SUPERIMPOSED WHEN COMPLETE COVERAGE IS REQUIRED,A MINIMUM OF THREE EXPOSURE TAKEN AT EITHER 60deg OR 120degree TO EACH OTHER SHALL BE MADE FOR EACH JOINT.
RECOMMENDED MINIMUM THICKNESS FOR WHICH RADIOACTIVE ISOTOPES MAY BE USED
MATERIALS MINIMUM THICKNESS IRIDIUM-192 COBALT-60
STEEL .75inch 1.50inch
COPPER .65inch 1.50inch
FOLLOWING ARE THE DEFECTS WHICH CAN NOT BE ACCEPTED 1. OFFSET OR MISMATCH WITH LACK OF PENETRATION2. LACK OF SIDE WALL FUSION3. TRANSVERSE CRACKS4. LONGITUDINAL CRACKS
OTHER DEFECTS WHICH CAN BE FIND OUT BY X-RAYS RADIOGRAPHY 1. EXTERNAL UNDERCUT2. INTERNAL UNDERCUT3. SCATTERED POROSITY4. CLUSTER POROSITY5. EXCESSIVE PENETRATION6. INTERPASS SLG INCLUSION
ABRASIVE BLASTING
IN FEW WE CALLED IT SAND BLASTING.ABRASIVE BLASTING IS THE OPERATION OF CLEANING A SURFACE BY FORCIBLY PROPELLING A STREAM OF ABRASIVE MATERIAL AGAINST IT.IN SIMPLE DEFINITION, USE A MATERIAL AGAINST ANOTHER MATERIAL TO MAKE IT SMOOTHE, REMOVE SURFACE CONTAMINANTS.
SURFACE CLEANLINESS AND ROUGHNESS ABRASIVE-BLASTED SURFACE ARE CHARACTERISED BY TWO KIND OF INFORMATION THAT ARE SURFACE CLEANLINESS & ROUGHNESS.CLEANLINESS REFLECTS THE DEGREE OF PRESENCE OF UNDESIRABLE RESUDUAL CONTAMINANTS ON SURFACES, WHEREAS ROUGHNESS REFERS TO THE MICROMATRIC SHAPE OF SURFACE, CALLED THE SURFACE PROFILE.
OPERATION ABRASIVE BLASTING IS A METHODOF PROPELLING ABRASIVE USING A COMPRESSED GAS OR PRESSURIZED LIQUID (WATER) AS A PROPELLANT.THERE ARE NUMEROUS GENERIC TERMS FOR THIS APPLICATION USUALLY RELATED TO THE ABRASIVE MEDIA IN USE, COMMON TERMS INCLUDE SAND BLASTING, SHOT BLASTING OR BLAST CLEANING.
SAND BLASTINGSAND BLASTING IS A GENERIC TERM FOR THE PROCESS OF SMOOTHING, SHAPING, AND CLEANING A HARD SURFACEBY FORCING SOLID PARTICLE ACROSS THAT SURFACE AT HIGH SPEED.SANDSBLASTING EQUIPMENT TYPICALLY CONSISTS OF A CHAMBER IN WHICH SAND AND AIR ARE MIXED.THE MIXTURE TRAVELS THROUGH A HAND-HELD NOZZLE TO DIRECT THE PARTICLE TOWARD THE SURFACE OF WORKPIECE.BORON CARBIDE IS A POPULAR MATERIAL FOR NOZZLES BECAUSE IT RESISTS ABRASIVE WEAR WELL.
.
TYPES OF ABRASIVES
1. SILICA SAND2. COAL OR SMELTER SLAG3. METALLIC, SYNTHETIC, AND MINERAL4. ORGANIC
EQUIPMENT THE MOST COMMON USED ARE COMMERCIAL BENCH-MOUNTED UNITS.THE CONSISTS OF A POWER SUPPLY AND MIXER, EXHAUST HOOD NOZZLE, AND GAS SUPPLY.EQUIPMENT FOR SAND BLASTING USUALLY CONSISTS OF BUT IS NOT LIMITED TO A HAND-HELD NOZZLE THAT DIRECTS A STREAM OF SAND PARTICLES OR OTHER MATERIAL TOWARD A WORKPIECE.THA SAND IS MIXED WITH AIR IN A MIXING CHAMBER IN ORDER TO TRANSPORT THE SAND TO THE NOZZLE WHERE IT IS SUBJECTED TO A HIGH VELOCITY AIR STREAM THAT PROPEL IT TOWARD THE WORKPIECE.
PAINTINGAFTER SAND BLASTING PROCESS, A VERY NECESSARY PROCESS TO SAVE THE TANK FROM RUST AND CORROSION, PAINTING IS DONE.TWO TIMES PAINTING IS NECESSARY.PAINTING THICKNESS ACCORDING TO REQUIREMENT THAT SHOULD NOT BE MORE THAN 2mm & 3mm.
REQUIRED PAINTS AND PAINT THICKNESS PAINT PRODUCT COLOUR DFT (MIC.) QTY
INTERTHANE870 GREY 80mic 100 lit.
INTERTHANE870 WHITE 80mic 100 lit.
FOR EACH TANK TOTAL 40 LITRE PAINT IS REQUIRED & 4 LITRE THINNER GTA 713 IS USED.
DISPATCHINGAFTER COMPLETING EACH AND EVERY MANUFACTURING & PAINTING PROCESS BULK STORAGE TANK IS DISPATCHED TO COCHIN SHIPYARD LIMITED WITH THE HELP OF BARGE.
LIST OF JOBS WHICH HAVE BEEN MANUFACTURED BY FEW ARE AS FOLLOWS
1. BULK STORAGE TANKS2. HEAT EXCHANGER3. STAEM COILS4. PIPE LINES5. NAPHTA SPLITTER
6. EXPANSION BELLOWS7. FUMES SCRUBBER FAN8. HATCH COVER9. MICRO BEND10. PEN STOCKS PIPE 11. SS EXPANSION BELLOWS
NOW FOUR JOBS ARE GOING UNDER FABRICATION FOR CPCL-
1. DISULFIDE COALESCER2. DISULFIDE SEPERATOR3. DEA SUMP4. FLARE KNOCKOUT DRUM
NAPHTHA SPLITTER WHICH IS VERY URGENTLY REQUIRED FOR CPCL IS COMPLETED. NOW THE JOBS WHICH ARE GOING UNDER FABRICATION ARE AS FOLLOWS
JOB ORDER NO. DESCRIPTION OF JOBS
8553 BULK STORAGE TANK
8572 U TUBE BUNDLE FOR MRPL
8610 U TUBE BUNDLE FOR FACT UD
8640 FUME SCRUBBER FAN
8571 NAPHTHA SPLLITER FOR CPCL
8570 PRESSURE VESSEL FOR CPCL
8568 NATURAL GAS CHILLED WATER EXCHANGER
8641 FACT PD-TUBULAR AIR PREHEATER 8639 STEAM COILS
8636 SS EXPANSION BELLOWS
8574 KMML FUEL OIL STORAGETANK
8579 SHELL ASSEMBLY FOR PHENOL COLUMNFOR HOCL
