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Transcript of Welding presentation

  • Welding Inspector4/23/20071 of 691

Main Responsibilities1.14/23/20072 of 691 Personal Attributes1.1Important qualities that good Inspectors are expected to have are:HonestyIntegrityKnowledgeGood communicatorPhysical fitnessGood eyesight4/23/20073 of 691 Standard for Visual Inspection 1.1 Basic Requirements 4/23/20074 of 691 Welding Inspection4/23/20071.25 of 691 Welding Inspection1.3Aids to Visual Inspection (to BS EN 970) When access is restricted may use: a mirrored boroscope a fibre optic viewing system welding gauges (for checking bevel angles, weld profile, fillet sizing, undercut depth) dedicated weld-gap gauges and linear misalignment (high-low) gauges straight edges and measuring tapes magnifying lens (if magnification lens used it should have magnification between X2 to X5)4/23/20076 of 691 Welding Inspectors Equipment1.3Measuring devices: flexible tape, steel ruleTemperature indicating crayonsWelding gaugesVoltmeterAmmeterMagnifying glassTorch / flash lightGas flow-meter4/23/20077 of 691 Welding Inspectors Gauges 10mm10mm1 2G.A.L.G.A.L.3 4LS.T.D. 16mmS.T.D. 16mm501/4 1/23/4HI-LO Single Purpose Welding Gauge61.3 Welding Inspectors Equipment4/23/20071.39 of 691 Welding Inspection 1.34/23/200710 of 691 Typical Duties of a Welding Inspector4/23/20071.511 of 691 Typical Duties of a Welding Inspector4/23/20071.512 of 691 Typical Duties of a Welding Inspector 1.5 Before Welding Equipment: all inspection equipment is in good condition & calibrated as necessary all safety requirements are understood & necessary equipment available Materials: can be identified & related to test certificates, traceability ! are of correct dimensions are in suitable condition (no damage/contamination)4/23/200713 of 691 Typical Duties of a Welding Inspector 1.5 Before Welding Consumables: in accordance with WPSs are being controlled in accordance with ProcedureWeld Preparations: comply with WPS/drawing free from defects & contaminationWelding Equipment: in good order & calibrated as required by Procedure4/23/200714 of 691 Typical Duties of a Welding Inspector 1.5 Before Welding Fit-up complies with WPS Number / size of tack welds to Code / good workmanship Pre-heat if specified minimum temperature complies with WPS 4/23/200715 of 691 Typical Duties of a Welding Inspector4/23/20071.516 of 691 Typical Duties of a Welding Inspector1.6During Welding Welding consumables in accordance with WPS in suitable condition controlled issue and handling Welding Parameters current, voltage & travel speed as WPS Root runs if possible, visually inspect root before single-sided welds are filled up4/23/200717 of 691 Typical Duties of a Welding Inspector1.6During Welding Inter-run cleaning in accordance with an approved method (& back gouging) to good workmanship standard Distortion control welding is balanced & over-welding is avoided4/23/200718 of 691 Typical Duties of a Welding Inspector1.6 4/23/200719 of 691 Typical Duties of a Welding Inspector1.6After Welding Repairs monitor repairs to ensure compliance with Procedure, ensure NDT after repairs is completed PWHT monitor for compliance with Procedure check chart records confirm Procedure compliance Pressure / Load Test ensure test equipment is suitably calibrated monitor to ensure compliance with Procedure ensure all records are available4/23/200720 of 691 Typical Duties of a Welding Inspector1.6After Welding Documentation ensure any modifications are on as-built drawings ensure all required documents are available Collate / file documents for manufacturing records Sign all documentation and forward it to QC department.4/23/200721 of 691 Summary of DutiesObserve To observe all relevant actions related to weld quality throughout production.Record To record, or log all production inspection points relevant to quality, including a final report showing all identified imperfectionsCompare To compare all recorded information with the acceptance criteria and any other relevant clauses in the applied application standard4/23/200722 of 691 Welding Inspector Terms & Definitions Section 24/23/200723 of 691 Welding Terminology & Definitions2.1 4/23/200724 of 691 Welding Terminology & Definitions2.1What is a Joint? The junction of members or the edges of members that are to be joined or have been joined (AWS) A configuration of members (BS499)4/23/200725 of 691 Joint Terminology 2.24/23/200726 of 691 Welded Butt Joints 2.2 __________ __________4/23/200727 of 691 Welded Tee Joints 2.2__________________4/23/200728 of 691 Weld Terminology 2.34/23/2007 Butt Preparations Sizes2.4Partial Penetration Butt Weld Actual Throat ThicknessDesign Throat ThicknessFull Penetration Butt WeldDesign Throat Thickness4/23/2007Actual Throat Thickness30 of 691 Weld Zone Terminology 2.5 FaceABWeld metal Heat Affected ZoneWeld BoundaryC4/23/2007D31 of 691 Weld Zone Terminology 2.5 Weld cap widthActual Throat ThicknessDesign Throat ThicknessExcess Root Penetration4/23/200732 of 691 Heat Affected Zone (HAZ) 2.54/23/200733 of 691 Joint Preparation Terminology 2.74/23/200734 of 691 Joint Preparation Terminology Angle of bevel4/23/20072.8 & 2.9Angle of bevel35 of 691 Single Sided Butt Preparations4/23/20072.1036 of 691 Double Sided Butt Preparations2.114/23/200737 of 691 Weld Preparation4/23/200738 of 691 Butt Weld - Toe Blend4/23/200739 of 691 Fillet Weld Features4/23/20072.1340 of 691 Fillet Weld Throat Thickness4/23/20072.1341 of 691 Deep Penetration Fillet Weld Features 2.134/23/200742 of 691 Fillet Weld Sizes2.14Calculating Throat Thickness from a known Leg Length: Design Throat Thickness = Leg Length x 0.7 Question: The Leg length is 14mm. What is the Design Throat? Answer: 14mm x 0.7 = 10mm Throat Thickness4/23/200743 of 691 Fillet Weld Sizes2.14Calculating Leg Length from a known Design Throat Thickness: Leg Length = Design Throat Thickness x 1.4 Question: The Design Throat is 10mm. What is the Leg length? Answer: 10mm x 1.4 = 14mm Leg Length4/23/200744 of 691 Features to Consider 22.14Importance of Fillet Weld Leg Length Size4/23/200745 of 691 Fillet Weld Profiles4/23/20072.1547 of 691 Fillet Features to Consider2.15EFFECTIVE THROAT THICKNESS a = Nominal throat thicknessas = Effective throat thicknesssDeep penetration fillet welds from high heat input welding process MAG, FCAW & SAW etc 4/23/200748 of 691 Welding Positions2.17PA1G/1FFlat/DownhandPB2FHorizontal-VerticalPC2GHorizontalPD4FPE4GPF3G/5GVertical-UpPG3G/5GVertical-DownHorizontal-Vertical(Overhead)OverheadH-L0456GInclinedPipe(Upwards)J-L0456GInclinedPipe(Downwards)4/23/200749 of 691 Welding Positions2.17ISO4/23/200750 of 691 Welding position designation 2.17 Butt welds in plate (see ISO 6947)Flat - PAOverhead - PEVertical up - PFVertical down - PG 4/23/2007Horizontal - PC 51 of 691 Welding position designation 2.17 Butt welds in pipe (see ISO 6947)Flat - PA axis: horizontal pipe: rotatedH-L045Vertical up - PF Vertical down - PG axis: horizontal pipe: fixedJ-L045axis: horizontal pipe: fixedHorizontal - PCaxis: inclined at 45 axis: inclined at 45 axis: vertical pipe: fixed pipe: fixed pipe: fixed4/23/200752 of 691 Welding position designation 2.17 Fillet welds on plate (see ISO 6947)Flat - PAHorizontal - PBVertical up - PF 4/23/2007Overhead - PDVertical down - PG 53 of 691 Welding position designation 2.17 Fillet welds on pipe (see ISO 6947)Flat - PAHorizontal - PBOverhead - PDaxis: inclined at 45 pipe: rotatedaxis: vertical pipe: fixedaxis: vertical pipe: fixedHorizontal - PB Vertical up - PF Vertical down - PG axis: horizontal pipe: rotated 4/23/2007axis: horizontal pipe: fixedaxis: horizontal pipe: fixed 54 of 691 Plate/Fillet Weld Positions4/23/20072.1755 of 691 4/23/200756 of 691 Welding Inspector Welding Imperfections Section 34/23/200758 of 691 Welding Imperfections3.14/23/200759 of 691 Welding Imperfections4/23/20073.160 of 691 Welding Imperfections4/23/20073.161 of 691 Welding imperfections classification3.1Cracks4/23/200762 of 691 Cracks3.1Cracks that may occur in welded materials are caused generally by many factors and may be classified by shape and position.Note: Cracks are classed as Planar Defects. 4/23/200763 of 691 Cracks4/23/20073.164 of 691 Cracks4/23/20073.165 of 691 Cracks3.2Main Crack Types 4/23/2007Solidification Cracks Hydrogen Induced Cracks Lamellar Tearing Reheat cracks66 of 691 Cracks3.2Solidification Cracking Occurs during weld solidification process Steels with high sulphur impurities content (low ductility at elevated temperature) Occur longitudinally down centre of weld4/23/200767 of 691 Cracks3.3Hydrogen Induced Cold Cracking Hydrogen enters weld via welding arc mainly as result of contaminated electrode or preparation Hydrogen diffuses out into parent metal on cooling Cracking developing most likely in HAZ4/23/200768 of 691 Lamellar Tearing3.5 Location: Parent metal Steel Type: Any steel type possible Susceptible Microstructure: Poor through thickness ductility Lamellar tearing has a step like appearance due to the solid inclusions in the parent material (e.g. sulphides and silicates) linking up under the influence of welding stressesLow ductile materials in the short transverse direction containing high levels of impurities are very susceptible to lamellar tearingIt forms when the welding stresses act in the short transverse direction of the material (through thickness direction)4/23/200769 of 691 Gas Cavities4/23/20073.670 of 691 Gas Cavities3.7PorosityRoot piping4/23/200771 of 691 Gas Cavities4/23/20073.872 of 691 Weld craterCrater pipe4/23/200773 of 691 Crater cracks (Star cracks)Crater pipe 4/23/2007 Solid Inclusions3.10Slag inclusions are defined as a non-metallic inclusion caused by some welding process Solid Inclusions4/23/20073.1176 of 691 Welding Imperfections3.13 welding current too low bevel angle too steep root face too large (sin