Example Slide of User Functions Time guide the slide should be finished by Lap Joints A fillet welded Lap joint* A spot welded Lap joint* Indicates a click is required to progress to the next element Relevant course text section:page/pages if applicable Text Page Ref 1:9/10

Terms & Definitions A Weld:* A union between materials caused by heat, and or pressure A Joint:* A configuration of members Text Page Ref 1:1

Types of Welds Butt welds:* Fillet welds:* Spot/Seam welds:* Plug/Slot welds:* Edge welds:*

Types of Joints Butt joints: * T joints: * Lap joints: * Corner joints:* Closed corner Open corner*

The more you take out, then the more you must put back in* Weld Preparations Remember, the purposes of a weld preparation is to allow access for the welding process, penetration and fusion through the area of the joint and its faces* The basic rule is this: The more you take out, then the more you must put back in* This has major effects on economics and distortion control etc The root face, root gap and angle of bevel values, the choice of single, or double sided preparations, are dictated only by the type of welding process, the position and accessibility of the joint*

Weld Preparations Angle of bevel* Root face* Included angle* Root gap* Root radius* Root landing*

Types of Single Butt Preparation Single bevel Single V Single J Single U*

Types of Double Butt Preparation Double bevel Double V Double J Double U*

Welded Joints Butt Joints A butt welded butt joint* A fillet welded butt joint* A compound welded butt joint*

Welded Joints T Joints A fillet welded T joint* A butt welded T joint* A compound welded T joint*

Welded Joints Lap Joints A fillet welded Lap joint* A spot welded Lap joint* A compound welded Lap joint*

Welded Joints Closed Corner Joints A fillet welded Closed Corner joint* A butt welded Closed Corner joint* A compound welded Closed Corner joint*

Welded Joints Open Corner Joints An inside fillet welded Open Corner joint* An outside fillet welded Open Corner joint* A double fillet welded Open Corner joint*

A Butt Welded Butt Joint Weld Face* Actual Throat Thickness* Weld Width* 1.2.3.4. Weld Toes* Design Throat Thickness* 1 2 A 3 4 B Fusion Boundary* HAZ* Weld Root* Fusion Zone* A + B = Excess Weld Metal**

Sizing of Fillet Welds Vertical Leg Length* Weld face*   Horizontal Leg Length* Excess weld metal ** Design throat* Actual throat*

Nominal & Effective Throat Thickness “a” = Nominal throat thickness “s” = Effective throat thickness   a s Deep throat fillet welds from FCAW & SAW etc*

Concave is preferred for joints subject to fatigue loading Fillet Weld Profiles Concave Mitre Convex * Concave is preferred for joints subject to fatigue loading

Very Poor Weld Toe Blend Angle Improved Weld Toe Blend Angle Effect of a Poor Toe Blend Angle 6 mm 80° Very Poor Weld Toe Blend Angle 3 mm* 20° Improved Weld Toe Blend Angle

Effect of a Poor Toe Blend Angle It is also possible that the height of excess weld metal is within the accepted limit of an applied standard, but the toe blend is unacceptable, as shown below* 90° 3 mm Extremely poor toe blend, but excess weld metal is within limits*

Summary of Terms Weld: A Union of materials Joint: A Configuration of members Weld Preparation: Preparing a joint to allow access and fusion. Types of Weld: Butt. Fillet. Spot. Seam Plug. Slot. Edge. Types of Joint: Butt. T. Lap. Corner (Open & Closed) Types of Preparation: Bevel’s. V’s. J’s. U’s. Single & Double Sided. Preparation Terms: Bevel/included angle. Root face/gap. Land/Radius Weldment Terms: Weld face & root. Fusion zone & boundary. HAZ. Weld toes.Weld width Weld Sizing (Butts): DTT. ATT. Excess weld metal. Weld Sizing (Fillets): DTT. ATT. Excess weld metal. Leg length *

Duties of a Welding Inspector It is the duty of all welding inspectors: To ensure that welding operations are carried out in accordance with written, or agreed practices or specifications Before During After * All Welding Operations Describe your duties to your code of practise. “CSWIP Exam”*

Duties of a Welding Inspector Discuss the following Before Welding: Safety: Legislation and safe working practices Documentation: Spec. Drawings. Procedures. Welder approvals. Certificates. Mill sheets Welding Process and ancillaries: Equipment. Cables. Regulators. Ovens. Quivers etc Incoming Consumables: Materials/welding consumables (Size. Condition. Specification. Storage) Marking out preparation & set up: Method. Angles/Root face/gap values. Distortion control. Pre-heat prior to tack welding if applicable*

Duties of a Welding Inspector During Welding: Pre-Heating. (Method and control) In process distortion control (Balance or sequence welding) Consumable control. (Correct baking and storage prior to use) Welding process (Related parameters i.e. volts/amps. gas flow rate) Welding run sequence and inter-pass cleaning Minimum/maximum Inter-pass temperatures Full compliance with all elements given on the WPS*

Duties of a Welding Inspector After Welding: Visual Inspection Non Destructive testing Repairs* Repair procedures (NDT/Excavation/Welding/Welder approval) PWHT Hydro-static testing Submission of all inspection reports to QC departments*

Responsibilities of a Welding Inspector To Observe Activities & Imperfections* Activities & Imperfections* To Record Activities & Imperfections* To Compare

Attributes of an effective Welding Inspector Some attributes/skills of an effective Welding Inspector:* Honest Literate Respected Dedicated Impartial Observant Decisive Analytical* Knowledgeable Experienced Record keeping skills Communication skills Safety conscious Inquisitive Responsible Diplomatic skills*

A Welding Inspectors Toolbox A Welding Inspectors toolbox should contain* A welding gauge (Cambridge style, or high low gauges etc) A tape measure and scale A wire brush A magnifying glass A torch and mirror A specification, pen and report, or note paper Any other aids to visual inspection*

Specialised Aids for Inspection Inspection may utilise the following specialised equipment:* Boroscopes (For assessing root runs in small Ø pipes) Flow-meter (For measuring gas flow rates in MIG/MAG/TIG) Simple NDT equipment (Penetrants and MPI) Complex NDT equipment (Radiography or Ultrasonics) Note: Both simple and complex NDT methods requires the specialised skills of qualified operators/technicians*

Welding imperfections can be categorized into groups: Imperfections in Welded Joints Welding imperfections can be categorized into groups: 1) Cracks 2) Gas Pores & Porosity 3) Solid Inclusions 4) Lack of fusion 5) Profile & Lack of Filling 6) Mechanical or Surface damage 7) Misalignment*

Cracks A HAZ hydrogen crack, initiated at the weld toe Most cracks are initiated from stress concentrations *

Surface breaking porosity Gas pores and Porosity Surface breaking porosity Shrinkage cavity*   Coarse cluster porosity Fine cluster porosity Blow hole > 1.6 mm Ø Hollow root bead   An isolated internal porosity

Solid Inclusions Surface breaking solid inclusion Internal solid inclusion causing a lack of inter-run fusion* Internal solid inclusion causing a lack of sidewall fusion Solid inclusions caused by undercut in the previous weld run Internal solid inclusion

Lack of Fusion Lack of sidewall fusion & incompletely filled grove* Overlap (Causing cold laps) Lack of inter-run fusion Lack of sidewall fusion Lack of root fusion

Profile Imperfections Spatter An Incompletely filled groove A Lack of root fusion Bulbous, or irregular contour Arc Strikes Poor toe blend B Incomplete root penetration *

Profile Imperfections Shrinkage grooves Root concavity   Crater pipe * Root oxidation in Stainless Steel Excess penetration, and burn through

Root Run or “Hot pass” undercut Undercut in Butt Welds Root Run or “Hot pass” undercut Parent metal, surface undercut   Weld metal, surface undercut*  

Weld metal, surface undercut Parent metal, “top toe” undercut* Undercut in Fillet Welds Weld metal, surface undercut Parent metal, “top toe” undercut*

Mechanical and Surface Damage Any surface damage caused by: Grinding Hammering/chisel marks Slag chipping hammer marks Torn cleats (Hammered off attachments) Arc strikes All of the above may cause serious weakness to the weld area*

Misalignment Linear Angular Excess weld metal height Lowest plate to highest point 3 mm Linear misalignment measured in mm Angular 15 Angular misalignment measured in degrees*

Mechanical Testing Which properties ?* 1) Hardness* 2) Toughness* Why ?* To establish the level of mechanical properties* Which properties ?* 1) Hardness* 2) Toughness* 3) Tensile strength* 4) Ductility*

What are Mechanical Properties? Describes the actions of “force & motion” Properties:* Something that makes one material useful for a job. These include the properties of: Hardness:* The ability of a material to resist indentation Toughness:* The ability of a material to absorb impact energy Tensile strength:* The ability to resist the action of a pulling force Ductility:* The ability to deform plastically under tension*

Introduction to Mechanical Testing We test welds to establish minimum levels of mechanical properties, and soundness of the welded joint* We divide tests into Quantitative & Qualitative methods:* 1) Quantitative tests: (Have units)* 2) Qualitative tests: (Have no units)*

Introduction to Mechanical Testing Types of tests include: Quantitative tests: Hardness tests Toughness tests Tensile strength tests* Qualitative tests: Macro tests Bend tests Fracture tests*

Testing the Weldment The test weld is usually cut into sections as follows: The location of specimens will depend upon the standard Charpy V test Bend test* Tensile test Macro/Hardness test Start/ Stop

Hardness Testing The specimen below has been polished and is ready to be hardness tested = Hardness Survey Thickness Base metal HAZ Fusion boundary Weld metal Further hardness surveys may be taken as the thickness of the specimen increases*

Hardness Testing Generally we use a diamond or steel ball to form an indentation We measure the width of the indentation to gauge the hardness*

Hardness Testing 1) Vickers Diamond Pyramid: Always uses a diamond* 2) Brinell hardness test: Always uses a steel ball* 3) Rockwell hardness test: Uses a ball, or diamond depending on the scale*

The specimen may be tested from different areas of the weld.* Charpy V Testing Machined notch 10 x 10 mm The specimen may be tested from different areas of the weld.* Graduated scale of absorbed energy in Joules* Pendulum Hammer Location of specimen

Toughness Testing 1) Charpy V test: 10 x 10 (Specimen horizontal) Joules* 2) Izod test: 10 x 10 (Specimen vertical) Ft.lbs* 3) CTOD test: Specimen used is actual design size. Detailed fracture report. mm*

Charpy V Testing Mn < 1.6 % increases toughness in steels* Joules absorbed Ductile Fracture Transition Zone 47 Joules Three specimens are normally tested at each temperature. 28 Joules Transition Temperature Range Brittle Fracture -40 -30 -20 -10 0 +10 +20 +30 + 40 Testing temperature

Transverse reduced test piece* Transverse Tensile Test A Section of weld is cut, or machined out across the test piece and tested in tension to failure. The units are usually in N/mm² Transverse reduced test piece*

Radius Reduced Transverse Tensile Test (For radius reduced test specimens only)   Weld   Test gripping area   HAZ   Direction of test   Reduced Section   Plate material   Used to assess the tensile strength of the weld metal

BS 709 / BS En 10002 All Weld Metal Tensile Testing Direction of the test * Tensile test piece cut along weld specimen.

Ductility Elongation % Firstly, before the tensile test 2 marks are made 50mm apart 50 mm During the test, Yield point & Tensile strength are measured The specimen is put together and the marks are re-measured 75 mm A new measurement of 75mm will indicate Elongation E50 %*

Macro Inspection 8) Poor Toe Blend* 1) Excess Weld Metal Height 7) Laminations 6)Porosity 2) Lack of Sidewall Fusion 5) Root Penetration 3) Lack of Root Fusion 4) Slag inclusion & Lack of inter-run fusion

Bend Tests Bend tests are used to establish fusion in the area under test Guide A Guided root bend test* Lack of root fusion shown here* Former Test Piece Force Further tests include face, side and longitudinal bend tests* For material over 12 mm thickness, side bend test may be used*

Bend Tests Specimen prior to test* Specimen after test*

Fillet Weld Fracture Tests 1 2 3 Saw cut Hammer blow X Line of fusion 3 1 Fracture line Full fracture X 3 2 1 2 Y Any strait line indicates a “Lack of root fusion”* Inspect both surfaces

Inclusions on fracture line* Butt Nick Break Tests Saw Cuts Hammer blow A Fracture line B Inspect both surfaces C Lack of root penetration or fusion Inclusions on fracture line*

Summary of Mechanical Testing We test welds to establish minimum levels of mechanical properties, and soundness of the welded joint We divide tests into Qualitative & Quantitative methods:* Quantitative: (Have units) Hardness (VPN & BHN) Toughness (Joules & ft.lbs) Strength (N/mm2 & PSI) Ductility/Elongation (E%) Qualitative: (Have no units) Macro tests Bend tests Fillet weld fracture tests Butt Nick break tests*

Macro Inspection The main difference between Macro & Micro is that Micro is the study of the micro-structure at much higher magnification The limit of Macro inspection is magnification < X 10 The specimen is usually cut from a stop/start in the test piece The cut specimen is polished to a fine finish (400 grit) The specimen must be inspected, before etching*

Macro Inspection Remember! The process of inspection is to first: Observe, then Report, then Compare!* Use the TWI macro sheets provided to observe and then make a report on a separate sheet of what you observe* When you have finished reporting, turn the macro sheet over and compare your observations with those given on the back of the sheet* (1 hour)

A systematic method of producing a sound weld* Welding Procedures A definition of the term “Procedure”?* A systematic method of producing an aim* Therefore, a “Welding procedure” is?* A systematic method of producing a sound weld*

What do “you” think about the following statements?* Welding Procedures What do “you” think about the following statements?* Do all welding procedures need to be written?* Most production welding procedure are formatted on written documents or computer spreadsheets, but they need not be written and may be a product of experience Do all welding procedures need to be approved?* Most procedures are approved, but not all? An approved welding procedure is one that has been tested to ensure that the procedure as carried out, produces a weld that satisfies a minimum level of quality for the mechanical, physical or chemical properties desired. If these are not required, then “procedural approval is unnecessary”*

Welding Procedures A Welding Procedure is a recipe of variable parameters, which will produce the same results of certain quality & properties if carried out in the same way each time* To evaluate a Provisional Welding Procedure we need to check if all the parameters set will work together to produce the desired results* .*

Welding Procedures Once the weld has been completed it is usually visually inspected, then Radiography or Ultrasonic testing is usually applied* Finally, and most importantly, Mechanically tested to ensure that the desired level of mechanical properties have been met* If all the desired properties have been met, then a procedure qualification record (WPQR or WPAR) is completed with all the test results, and the procedure then becomes qualified* From this data, a workable document for production welding is prepared and called a Welding Procedure Specification. (WPS)* A CSWIP 3.2 Senior Welding Inspector is normally responsible for the testing and approval of welding procedures*

Welding Procedures Examples of “Extents of Approval” include:* a) Diameter of pipe, or thickness of plate Welding position, amperage range, or number of runs Process (On multi process procedures only) Certain material groups Change of consumable to one of the same classification Only if the class is given in the original procedure f) Heat input range (kJ/mm)*

Welder Approval Once the procedure has been approved it is then important to test each welder, to ensure that he has the skill to reach the minimum level of quality in the weld, as laid down in the application standard* There is no need to carry out the mechanical tests of the procedure, although bend tests are often used to ensure good side wall fusion Normally; visual, x ray, bends, fractures and macro’s are used in welder approval tests*

Welder Approval When supervising a welder test the welding inspector should:*   1)    Check the welding process, condition of equipment and test area for suitability. 2)    Check that extraction systems, goggles and all safety equipment are available. 3)    Check grinders, chipping hammers, wire brush and all hand tools are available. 4)    Check materials to be welded are correct and stamped correctly for the test. 5)    Check welding consumables specification, diameter, and treatment with WPS. 6)    Check the welder’s name and stamp details are correct. 7)    Check that the joint has been correctly prepared and tacked, or jigged. 8)    Check that the joint and seam is in the correct position for the test. 9)    Explain the nature of the test and check that the welder understands the WPS. 10)  Check that the welder carries out the root run, fill and cap as per the WPS. 11)  Ensure welders identity and stop start location are clearly marked. 12)  Supervise or carry out the required tests and submit results to Q/C department.* A CSWIP 3.1 Welding Inspector is normally responsible for the supervision and testing of welder approvals *