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AWS Qualification Program. Dr. Eng. Hamed A. Nagy Weld-Inspecta Engineering Services Company. WELDING INSPECTION AND CERTIFICATION. In today’s world there is increasing emphasis on the need for quality. Weld quality is an important part of the quality effort.

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Aws qualification program

AWS Qualification Program

Dr. Eng. Hamed A. Nagy

Weld-Inspecta Engineering Services Company


Welding inspection and certification
WELDING INSPECTION AND CERTIFICATION

  • In today’s world there is increasing emphasis on the need for quality.

  • Weld quality is an important part of the quality effort.

  • This concern for product quality is due to several factors, including economics, safety, government regulations, global competition, and the use of less conservative designs.

  • In reality, many people participate in the creation of a quality welded product.

  • The welding inspector is one of the “front line” individuals who must check to see if all of the required manufacturing steps have been completed properly.


Welding inspection and certification1
WELDING INSPECTION AND CERTIFICATION

  • Section 4 of “AWS QC1, Standard for Qualification and Certification of Welding Inspectors.” outlines the various responsibilities of the welding inspector.

  • A successful quality control program begins before the first arc is struck.

  • Before welding, the inspector will check drawings and specifications to determine such information as the configuration of the component, its specific weld quality requirements, and what degree of inspection is required.

  • Once welding begins, the welding inspector may observe various processing steps to assure that they are done properly.

  • Final inspection should simply confirm the success of those operations.


Welding inspection and certification2
WELDING INSPECTION AND CERTIFICATION

  • The ten modules listed below are sources for examination information.

  • Module 1 : Welding Inspection & Certification

  • Module 2 : Safe Practices for Welding Inspectors

  • Module 3 : Metal Joining and Cutting Processes

  • Module 4 : Weld Joint Geometry and Symbols

  • Module 5 : Documents Governing Welding Inspection and Qualification


Welding inspection and certification3
WELDING INSPECTION AND CERTIFICATION

  • Module 6 : Metal Properties and Destructive Testing

  • Module 7 : Metric Practice for Welding Inspection

  • Module 8 : Welding Metallurgy for the Welding Inspector

  • Module 9 : Weld and Base Metal Discontinuities

  • Module 10 : Visual Inspection and Other NDE Methods


Who is the welding inspector
Who is the Welding Inspector ?

  • The welding inspector is a responsible person, involved in the determination of weld quality according to applicable codes and/or specifications.

  • The inspection workforce may include destructive testing specialists, nondestructive examination (NDE) specialists, code inspectors, military or government inspectors, owner representatives, in-house inspectors, and others. These individuals may, at times, consider themselves ‘welding inspectors. , since they inspect welds as part of their job responsibility.


Who is the welding inspector1
Who is the Welding Inspector ?

  • Overseer

  • Specialist

  • Combination Overseer – Specialist

  • It is common to see inspectors servicing as both overseer and specialist.

  • For the purposes of this course we will refer to the welding inspector in general, without regard to how each individual will be used by an employer.

  • It is impractical to address each individual’s situation in the scope of this discussion.


  • Important qualities
    Important Qualities

    • 1-Professional attitude:

    • Determines the degree of respect and cooperation received from others during the performance of inspection duties.

    • Ability of the welding inspector to make decisions based on facts so that inspectors are fair, impartial and consistent.

    • Familiarity with the job requirements so that decisions are neither too critical nor too lax.

    • Inspectors will often find themselves being ‘tested’ by other personnel on the job, especially when newly assigned to some task. Maintaining a professional attitude helps overcome obstacles to successful job performance.


    Important qualities1
    Important Qualities

    • 2- Physical condition:

    • Should have good vision, whether natural or corrected. The AWS CWI program requires a minimum 20/40 visual acuity, natural or corrected, and the completion of a color perception test.

    • Should be in good enough physical condition to go to any location where the welder has been. This does not imply that inspectors must violate safety regulations just to do their duties.


    Important qualities2
    Important Qualities

    • 3- Knowledge:

    • To understand and apply the various documents describing weld requirements. These can include drawings, codes, standards and specifications.

    • Documents provide most of the information regarding what, when, where and how the inspection is to be done.

    • It is important that these documents are reviewed before the start of any work or production, because the welding inspector must be aware of the job requirements.

    • Often this pre-job review will reveal required “hold points” for inspections, procedure and welder qualification requirements.

    • Requirements should be memorized. These are reference documents and should be readily available for detailed information any time in the fabrication process.


    Important qualities3
    Important Qualities

    • 4. Experience:

    • Better ways of thinking and working will develop with time.

    • Experience will also help the inspector develop the proper attitude and point of view regarding the job.

    • We often see a novice inspector paired with an experienced one so the proper techniques can be passed along.

    • 5. Safe work habits:


    Important qualities4
    Important Qualities

    • Records:

    • All records developed should be understandable to anyone familiar with the work. Reports that can only be deciphered by the welding inspector are useless when he or she is absent. Therefore, neatness is important as well.

    • The welding inspector should look at these reports as his or her permanent records should a question arise later.

    • When reports are generated, they should contain information regarding how the inspection was done so it can be duplicated later by someone else with similar results.


    Important qualities5
    Important Qualities

    • There are few “rules of etiquette” relating to inspection reports.

    • First, they should be completed in ink, or typewritten.

    • If an error is made in a hand written report, it can be single-lined out and corrected (the error should not be totally obliterated). This corrective action should then be initialed and dated.

    • The report should also accurately and completely state the job name and inspection location as well as specific test information.

    • Use of sketches and pictures may also help to convey information regarding the inspection results. Then the completed report should be signed and dated by the inspector who did the work.


    Ethical requirements
    Ethical Requirements

    • Ethics simply detail what is considered to be common sense and honesty.

    • The welding inspector’s position also carries with it a certain responsibility to the public.

    • So, it is their responsibility to report any condition that could result in a safety hazard.

    • If the inspector is involved in a dispute regarding the inspection, he or she may be asked to publicly express an opinion.

    • Probably the best way to deal with public statements, however, is simply to avoid them whenever possible.


    Ethical requirements1
    Ethical Requirements

    • The inspector should not volunteer information just to gain publicity.

    • However, in some situations, the welding inspector may wish to solicit the advice of a legal representative before speaking.

    • Many inspectors are required to make decisions that may have great financial impact on certain parties.


    Wi as a communicator
    WI as a Communicator

    • Communication is not a one way street.

    • Communication sequence must be a continuous loop so that both parties have an opportunity to express their thoughts or interpretations.

    • It is wrong for any individual to think that their ideas will always prevail.

    • Welding inspectors may be the central figure of the communication network.

    • Some people that the inspector may communicate with are welders, welding engineers, inspection supervisors, welding supervisors, welding foremen, design engineers, and production supervisors.

    • Suppose the welders are asked to weld a joint having a root opening which is so tight that a satisfactory weld cannot be accomplished.


    Wi as a communicator1
    WI as a Communicator

    • Communication between the welder and an inspector is usually improved if the welding inspector has some welding experience.

    • Welding engineers rely heavily on welding inspectors to be their “eyes” on the shop floor or, construction site to spot problems relating to the techniques and processes specified.

    • If a welding procedure is not producing consistent, reliable results, the welding inspector may be the first person to spot the problem.

    • In some situations, instead of communicating directly with the welders, the welding inspector will deal with the welding supervisor or foreman.

    • The welding inspector may also have to gain information form design engineers about the actual weld requirements.


    Wi as a communicator2
    WI as a Communicator

    • Another way in which this aspect of communication takes place is through drawings and welding symbols.

    • Finally, the welding inspector will have some occasion to discuss job scheduling with production personnel.

    • .

    • Several ways in which people effectively communicate. They include speaking, writing, drawing, gesturing, and the use of pictures or photographs.


    Certification
    CERTIFICATION

    • The American Society for Nondestructive Testing has issued guidelines for certification of NDE personnel in ASNT SNT TC-1A.

    • This document describes the recommended procedures for certifying inspectors performing nondestructive testing. ASNT recognizes three levels of certification, Levels I, II, and III.

    • The document AWS QC-G, Guide to AWS Qualification and Certification, provides the necessary applications and background information.

    • AWS QC-1 Standard for AWS Certification of Welding Inspectors establishes the requirements for AWS certification of welding inspection personnel, describes how personnel are qualified, lists the principles of conduct, and notes the practice by which certification may be maintained.


    Certification1
    CERTIFICATION

    • Experience:

    • Candidates with a high school education, either by diploma or state or military equivalency, must have at least 5 years experience.

    • With supporting documentation (e.g., copies of transcripts, reference letters, credited hours of training, quarter hours or semester hours) up to two years of work experience may be substituted for post high school educational experience. Substituted educational experience includes as Associate or higher degree in engineering, physics or physical science and welding technology.

    • Trade and vocational courses can be applied to work experience substitution for completed courses related to welding (up to one year maximum).


    Certification2
    CERTIFICATION

    • Individuals with eighth grade schooling are required to have not less than 10 years job experience to qualify for the examination.

    • For individuals with less than eighth grade schooling, not less than 15 years is required.

    • A subordinate level of qualification is the Certified Associate Welding Inspector (CAWI), which requires fewer years of experience for each educational level.

    • Individuals who qualify for the Certified Welding Inspector Examination take a three-part examination.


    Certification3
    CERTIFICATION

    • Part A – Fundamentals.

    • The Fundamental examination is a closed book test consisting of 150 multiple choice questions.

    • The topics covered in this portion of the exam include reports and records, destructive tests, welding performance, duties and responsibilities, weld examination, definitions and terminology, safety, welding and nondestructive examination symbols, nondestructive examination methods welding processes, heat control, metallurgy, mathematical conversions and calculations.


    Certification4
    CERTIFICATION

    • Part B – Practical.

    • The Practical examination consists of 46 questions.

    • It requires measurement of weld replicas with provided measuring tools, and evaluation in accordance with a supplied “Book of Specifications”.

    • Not all questions require the use of the Book of Specifications; they do require the individual to answer from practical knowledge.

    • The Practical Test covers welding procedures, welder qualification, mechanical tests and properties, welding inspection and flaws, and nondestructive test. Test candidates should be familiar with fillet and butt weld gages, micrometer, dial calipers, and machinist’s scale.


    Certification5
    CERTIFICATION

    • Part C – Open Book Code.

    • This portion consists of 46 questions on the code the individual has selected for this part of the examination.

    • AWS D1.1.

    • API 1104.

    • ASME B31.1.

    • ASME Section VIII.

    • ASME Section IX.

    • MIL-STD-1689 (SH) (83).

    • MIL-STD-248D(89).


    Certification6
    CERTIFICATION

    • The passing score in each part for the CWI is 72 percent; the passing for CAWI is 50 percent.

    • Part of the welding inspector’s job is there view and interpretation of various documents relating to the welded fabrication.

    • This requires that the individual have a full understanding of the proper terms and definitions that are used.

    • ANSI/AWS A3.0 was developed by the Committee on Definitions and Symbols to aid in welding information communication.

    • When non-standard terms are mentioned, they appear in parentheses after the preferred words.


    Certification7
    CERTIFICATION

    • While most of the terms used apply to the actual welding operation, it is important for the welding inspector to understand other definitions which apply to other related operations.


    Joining cutting processes
    JOINING & CUTTING PROCESSES

    • There are certain aspects of the various joining and cutting processes which the successful welding inspector must understand in order to perform most effectively.

    • First, the inspector should realize the important advantages and limitations of each process.

    • The inspector should also be aware of those discontinuities which may result when a particular process is used.


    Joining cutting processes1
    JOINING & CUTTING PROCESSES

    • Some discontinuities can occur during the application of a particular process.

    • When the welding inspector has some understanding of these process fundamentals, he or she is better prepared to perform visual welding inspection. The inspector who is capable of spotting problems in-process will be a definite asset to both production and quality control.

    • Production elders will have greater respect for the inspector and resulting decisions.


    Joining cutting processes2
    JOINING & CUTTING PROCESSES

    • The processes discussed here can be divided into three basic groups: welding, brazing and cutting.

    • The Welding Processes can be divided into seven groups, Arc Welding, Solid State Welding, Resistance Welding, Oxyfuel Gas Welding, Soldering, Brazing, and Other Welding.

    • The Allied Processes include Thermal Spraying, Adhesive Bonding, and Thermal Cutting (Oxygen, Arc and Other Cutting).


    Welding processes
    WELDING PROCESSES

    • According to AWS, a weld is, “a localized coalescence of metals or nonmetals produced either by heating the materials to the welding temperature, with or without the application of pressure, or by the application of pressure alone and with or without the use of filler metal”.

    • Process features include a source of energy to provide heating, a means of shielding the molten metal from the atmosphere, and a filler metal (optional with some processes and joint configurations).


    SMAW

    • Shielded Metal Arc welding.

    • It is referred to also as “stick welding”.

    • This process operates by heating the metal with an electric are between a covered metal electrode and the metals to be joined.

    • The arc is created between the electrode and the work piece due to the flow of electricity.

    • This arc provides heat, or energy, to melt the base metal, filler metal and electrode coating.


    SMAW

    • As the welding arc progresses, it leaves behind solidified weld metal covered by a layer of converted flux, referred to as slag.

    • Slag tends to float to the outside of the metal since it solidifies after the molten metal has solidified.

    • Another feature is the presence of shielding gas which is produced when the electrode coating is heated and decomposed.

    • Electrode is made up of a solid metal core wire covered with a layer of granular flux held in place by some type of bonding agent.


    SMAW

    Electrode Covering

    Shielding atmosphere

    Core Wire

    Metal & Slag Droplets

    Depth of Penetration

    Direction of Welding


    SMAW

    Base or Parent Metal

    Slag

    Weld Metal


    SMAW

    • All carbon and low alloy steel electrodes use essentially the same type of steel core wire, a low carbon, rimmed steel.

    • Any alloying is provided form the coating, since it is more economical to achieve alloying in this way.

    • The electrode coating serves five separate functions:

    • Shielding.

    • Deoxidation.

    • Alloying.

    • Ionizing.

    • Insulating. (minor effect).


    SMAW

    Eletrode

    Position

    E X XXX

    Coating & Operating Characteristics

    Strength


    SMAW

    • AWS Specifications A5.1 and A5.5 describe the requirements for carbon and low alloy steel electrodes, respectively.

    • AWS Classification:

    • The identification consists of an “E”, which stands for electrode, followed by four or five digits.

    • The first two, or three, numbers refer to the minimum tensile strength of the deposited weld metal in ksi.


    SMAW

    • The next number refers to the positions which the electrode can be used:

    • A “1” indicates the electrode, is suitable for use in any position.

    • A “2” means that the molten metal for the flat or horizontal fillet positions.

    • A “4” means the electrode is suitable for welding in a ‘downhill’ progression.

    • The number “3” has no designation.

    • The last number describes other characteristics which are determined by the composition of the coating present on the electrode.


    SMAW

    • This coating will determine its operating characteristics and recommended electrical current: AC (alternating current), DCEP (direct current, electrode positive) or DCEN (direct current, electrode negative).

    • Electrodes ending in “5” “6” or “8” are classified as ‘low hydrogen’ types.

    • To maintain this low hydrogen (moisture) content, they must be stored in their original factory-sealed container or an acceptable storage oven.

    • This oven should be heated electrically and have a temperature control capability in the range of 150º to 350ºF.


    SMAW

    • Since this device will assist in the maintenance of a low moisture content (less than 0.2%), it must be suitably vented. Any low hydrogen electrodes .

    • Most codes require that low hydrogen electrodes be held at a minimum oven temperature of 250F (120ºC) after removal form their sealed container.

    • Electrodes other than those mentioned above may be harmed if placed in the oven.

    • Those SMAW electrodes used for joining low alloy steels may also have an alpha-numeric suffix which is added to the standard designation after a hyphen.


    SMAW

    • Suffix Major Alloy Elements(s)

    • A1 0.5% Molybdenum

    • B1 0.5% Molybdenum-0.5% Chromium

    • B2 0.5% Molybdenum-1.25% Chromium

    • B3 1.0% Molybdenum-2.25% Chromium

    • B4 0.5% Molybdenum-2.0% Chromium

    • C1 2.5% Nickel

    • C2 3.5% Nickel

    • C3 1.0% Nickel

    • D1 0.3% Molybdenum-1.5% Manganese

    • D2 0.3% Molybdenum-1.75% Manganese

    • G* 0.2% Molybdenum; 0.3% Chromium;

    • 0.5% Nickel; 1.0% Manganese; 0.1%

    • Vanadium

    • * Need to have minimum content of one element only.


    SMAW

    • The power source for SMAW is referred to as a constant current power supply, having a “drooping” characteristic.

    • As the welder draws the electrode away from the work piece, the arc length increases which reduces the current, and consequently, reduces the heat input to the weld.

    • Because the lower curve has less slope than the upper curve, a greater change in arc current is obtained from a given change in arc length (voltage).

    • SMAW is used in most industries for numerous applications. It is used for most materials except for some of the more exotic alloys.

    • SMAW remains as a popular process which will continue to be in great use by the welding industry.


    SMAW

    Max. OCV

    Voltage

    Min. OCV

    Current, A


    SMAW

    • Advantages:

    • equipment is relatively simple and inexpensive.

    • So, quite portable (Numerous gasoline or diesel engine-driven types and also, some so small and lightweight of the newer solid state power sources).

    • Availability of numerous types of electrodes, the process is considered quite versatile.

    • Cheapness of alloying.


    SMAW

    • Limitations:

    • 1- Speed (Productivity): Periodically change of stick (14 or 18 inches in length)

    • + Cleaning between passes.

    • 2- low hydrogen type electrodes require storage in an appropriate electrode holding oven which will help to maintain their low moisture levels.


    SMAW

    • Associated Discontinuities:

    • 1- Porosity: Presence of moisture or contamination in the weld region. It could be present in the electrode coating, on the surface of the material, or come from the atmosphere surrounding the welding operation + “long arcing”. + Arc blow.

    • There is a perpendicular magnetic field developed whenever an electric current is passed through a conductor.

    • Magnetic Field can be visualized as a series of concentric circles surrounding the conductor.

    • This magnetic field is strongest when contained entirely within a magnetic material and resists having to travel through the air outside this magnetic material.


    SMAW

    Forward Blow

    Back Blow

    Current Direction

    Travel


    SMAW

    • Consequently, field can become distorted when the arc approaches the edge of a plate, the end of a weld or some abrupt change in contour of the part being welded.

    • To reduce the effects of arc blow, several alternatives can be tried. They include :

      • Change from DC to AC.

      • Hold as short an arc as possible.

      • Reduce welding current.


    SMAW

    • Angle the electrode in the direction opposite the arc blow.

    • Use heavy tack welds at either end of a joint, with intermittent tack welds along the length of the joint.

    • Weld toward a heavy tack or toward a completed weld.

    • Use a backstep technique.

    • Weld away from the ground to reduce back blow; weld toward the ground to reduce forward blow.

    • Ground the work piece at both ends of the joint to be welded.

    • Wrap ground cable around the work piece and pass ground current through it in such a direction that the magnetic field set up will tend to neutralize the magnetic field causing the arc blow.

    • Extend the end of the joint by attaching runoff plates.


    SMAW

    • 2- Arc blow can also cause spatter, under out, improper weld contour, and decreased penetration.

    • 3- Such as any process incorporating a flux, the possibility of trapping slag within the weld deposit is a definite concern. Solution: electrode Manipulation + Interpass cleaning.

    • 4- Improper manipulation of the electrode could cause incomplete fusion, incomplete joint penetration, cracking, undercut, overlap, incorrect weld size, and improper weld profile.


    GMAW

    Voltage

    Current, A


    Solid Wire

    Electrode Rod

    ER X X S X

    Chemical Composition

    Strength


    CC & OC

    Electrode

    Position

    E X X X-X

    Strength

    Tubular


    Electrode

    Condition of HT

    Electrode

    F X XX-EXXX

    Strength

    For Impact

    Flux


    Contact Tube

    Gas Nozzle

    Electrode Consumable

    Setback

    Electrode Extension

    Stickout

    Standoff Distance

    Arc Length


    Travel

    Contact Tube

    Flux from Hopper

    Electrode Consumable

    Slag

    Weld Pool

    Solidified Metal


    Travel

    I. Transferred Arc

    Tungsten Electrode

    Constricting Nozzle

    Secondary Shielding Gas

    +

    Filler Metal

    Orifice Gas


    Travel

    II. Nontransferred Arc

    Tungsten Electrode

    Constricting Nozzle

    Secondary Shielding Gas

    Filler Metal

    Orifice Gas

    +


    Back Cap

    Shielding Gas In

    Gas Nozzle

    Collet Body

    Nonconsumable Electrode

    Filler Metal

    Travel


    I. Spray Mode

    II. Globular Mode

    III. Short Circuiting Mode


    Electrode Guide Tube

    Molten Slag

    Molten Metal

    Water Out

    Solidified Metal

    Water In

    Water Cooled Copper Shoes


    Emitter (Cathode)

    Grid (Cup)

    Anode

    Magnetic Focusing Lens

    Magnetic Deflection Coil

    Focal Range




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