Lesson 1Distortion prevention: stitch welds, backstep technique, clamping, low heat input processes, balanced welding sequence, and pre-bending allowanceDis section explain how to stop bend using stitch welds, backstep ways, clamping, low heat input processes, balanced welding order, and pre-bend allowances fit for 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 fillersDis section explain stop measures against hot cracking, focus on filler metal pick, heat input control, bead order, and use of stabilized or low-carbon fillers to handle solidification mode and leftover stress.
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 planningDis section address repair and fix of bend, cover mechanical straightening, controlled local heating, plan re-welding, and check against acceptance criteria to decide correction, rework, or okay.
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 distributionDis section explore bend and warping ways in round shells and brackets, focus on long and cross shrinkage, uneven heat spread, and how joint layout and welding 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 techniqueDis section detail how joint prep, parameter pick, and welder skill work together to stop no fusion and penetration defects, stress steady setups, check steps, and paper of qualified procedures.
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-inspectionDis section detail post-weld fix of holes, including grind out bad areas, controlled re-welding, optional backing or vacuum support, and final re-check to verify quality standards.
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)Dis section analyze hot cracking ways in stainless welds, link make-up, dirt levels, joint hold, and heat input to solidification and grain cracking, stress know risk conditions 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 inspectionDis section cover plan repair of hot cracking, including stop-drill, gouge or grind, controlled re-welding, and full post-weld cleaning and check to make sure cracks all gone and no come back.
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 filletsDis section clear how no fusion and no penetration happen in round butt joints and fillet welds, link joint shape, access, position, and skill to usual defect spots and check focus 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 manipulationDis section show practical ways to stop holes, stress cleaning methods, gas pick and flow control, travel skill, purge check, and weld pool work to let gases out before hard.
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 limitsDis section outline repair ways for no fusion and penetration, including defect removal by grind, qualified re-weld procedures, preheat and interpass controls, and NDT acceptance criteria 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 gasesDis section check hole forming in stainless welds, relate dirt, no enough shielding, purge fail, and gas trap to hole shape, and show how joint design and position affect gas escape paths.
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
