Lesson 1Distortion prevention: stitch welds, backstep technique, clamping, low heat input processes, balanced welding sequence, and pre-bending allowanceExplains stopping bend with stitch welds, backstep tricks, clamping, low heat methods, balanced weld order, and pre-bend plans suited to joint shape and material thickness.
Stitch welding and skip sequence planningBackstep technique for shrinkage controlUse of clamps, strongbacks, and fixturesLow heat input processes and passesPre-bending and presetting componentsLesson 2How to prevent hot cracking: filler selection, heat input control, bead sequencing, and use of stabilized/low-carbon fillersExplains steps against heat cracking, focusing on filler pick, heat control, bead order, and stabilised or low-carbon fillers to handle freezing mode and leftover stresses.
Selecting fillers for proper ferrite balanceUsing stabilized and low-carbon filler gradesHeat input limits and interpass temperatureBead sequencing to spread shrinkagePreheat and cooling control for crack resistanceLesson 3Repair/mitigation of distortion: mechanical straightening, local heating, re-welding strategy, acceptance criteria and rework planningAddresses fixing and easing bend, covering mechanical straightening, controlled local heat, planned re-welding, and checks against okay limits to choose fix, redo, or accept.
Measuring distortion and recording baselinesMechanical jacking, pressing, and peeningLocal heat straightening proceduresRe-welding strategies to counter shrinkageAcceptance criteria and repair documentationLesson 4Distortion and warping mechanisms in circumferential shells and brackets: longitudinal and transverse shrinkage, uneven heat distributionExplores bend and warp causes in round shells and brackets, focusing on length and width shrink, uneven heat spread, and how joint layout and weld order affect final shape.
Longitudinal shrinkage around circumferencesTransverse shrinkage and ovality in shellsBracket-induced local bending and twistHeat input distribution around the jointPredicting distortion from weld size and pathLesson 5Three-pronged prevention methods for fusion/penetration defects: joint prep, parameter control, and techniqueDetails how joint prep, setting picks, and welder skills work together to stop missing fusion and depth faults, stressing steady setups, checks, and records of approved methods.
Joint design, bevel angle, and root face selectionRoot opening, land, and fit-up tolerancesCurrent, voltage, and travel speed windowsArc length, electrode angle, and manipulationVerification of fusion with visual and NDT checksLesson 6Repair and post-weld remediation of porosity: grinding, re-weld, vacuum backing if needed, and re-inspectionDetails post-weld fixing of holes, including grinding bad spots, controlled re-welding, optional backing or vacuum help, and final re-check to meet quality rules.
Identifying porosity extent with NDTGrinding and blending porous regionsRe-welding techniques to avoid repeat poresUse of backing bars or vacuum assistanceFinal inspection, records, and traceabilityLesson 7Hot cracking (solidification cracking/intergranular cracking): root causes in stainless (composition, high sulfur/phosphorus, restraint, heat input)Analyses heat cracking in stainless welds, linking makeup, dirt levels, joint hold, and heat to freezing and grain cracks, stressing spotting risk in production.
Solidification cracking in austenitic stainless weldsIntergranular hot cracking along grain boundariesEffects of sulfur and phosphorus impuritiesInfluence of joint restraint and fit-upHeat input, cooling rate, and crack susceptibilityLesson 8Repair strategies for hot cracking: stop-drill and gouge, re-weld with controlled heat input, post-weld cleaning and inspectionCovers planned fixing of heat cracking, including stop-drill, gouge or grind, controlled re-weld, and full post-weld clean and check to ensure cracks gone and no return.
Crack mapping, marking, and extent assessmentStop-drill techniques to arrest crack growthGouging and grinding to sound metalControlled re-weld with adjusted heat inputPost-weld cleaning, NDT, and documentationLesson 9Lack of fusion and lack of penetration: how they occur on circumferential butt joints and filletsClarifies how missing fusion and depth happen in round butt joints and fillets, linking joint shape, reach, position, and skill to usual fault spots and check areas.
Root fusion problems in pipe butt weldsSidewall fusion loss in narrow groovesLack of penetration in double-sided weldsFillet weld throat and leg size issuesInspection focus zones on circumferential weldsLesson 10Prevention strategies for porosity: cleaning, gas control, travel technique, purge integrity, and weld pool manipulationPresents practical ways to stop holes, stressing cleaning, gas pick and flow control, travel skill, purge checks, and pool handling to let gases out before freeze.
Pre-weld cleaning and degreasing proceduresShielding gas composition and flow settingsTorch angle and travel speed for gas escapePurge dams, venting, and leak testingStringer versus weave beads for porosity controlLesson 11Repair methods for lack of fusion/penetration: grind-out, re-weld procedures, preheat/interpass controls, and NDT acceptance limitsOutlines fixing methods for missing fusion and depth, including grind removal, approved re-weld plans, preheat and between-pass controls, and NDT okay limits before final okay.
Locating fusion defects with UT and radiographyGrinding and carbon arc gouging techniquesRe-weld parameters for full penetrationPreheat and interpass temperature controlApplying code NDT acceptance limitsLesson 12Porosity causes in stainless welds: contamination, inadequate shielding, purge failures, and entrapment of gasesExamines hole formation in stainless welds, linking dirt, poor gas cover, purge fails, and gas trap to hole shape, and how joint design and position affect gas escape.
Surface contaminants and moisture sourcesShielding gas flow, turbulence, and draftsBack purging failures in root passesGas entrapment in deep or narrow groovesRecognizing porosity patterns in radiography
