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    Technology Vocational Livelihood: Shielded Metal Arc Welding

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    jonquintano

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    Technology Vocational Livelihood: Shielded Metal Arc Welding

    Uploaded by

    jonquintano
    358 views9 pages

    Original Title

    VALIDATED-TVL-SMAW11-Q3-M-5

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    358 views9 pages

    Technology Vocational Livelihood: Shielded Metal Arc Welding

    Uploaded by

    jonquintano

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
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    of 9

    Technology

    Vocational Livelihood 12
    Shielded Metal Arc Welding

    Quarter 3
    Self-Learning Module 5
    TITLE: LOCATE WELD DEFECTS
    Writer: Antonio F. Quines
    Reviewer: Orlando A. Joven Jr (Validator)
    Cerina Galoy (Grammarian)
    EXPECTATIONS

    At the end of this module, the learners will be able to

    A. define the different kinds of Weld Defects;


    B. enumerate the different kinds of Weld Defects; and
    C. value the importance of understanding weld defects.

    PRETEST

    Directions: Match column A with the correct answer on column B, write only the

    letter of answer on the blank provided before each number.

    A B
    a. Porosity ______1. When the base of metal melts away from the weld zone,
    then a groove is formed in the shape of a notch, then this type of
    defect is known as Undercut. It reduces the fatigue strength of the
    joint.
    b. Undercut ______2. This is the most unwanted defect of all the other welding
    defects. Welding cracks can be present at the surface, inside of the
    weld material or at the heat affected zones.
    c. Overlap ______3When some metal drops are expelled from the weld and
    remain stuck to the surface, then this defect is known as Spatter.
    d. Spatter _____4. Porosity in the condition in which the gas or small bubbles
    gets trapped in the welded zone.
    e. Weld Crack _____5. When the weld face extends beyond the weld toe, then this
    defect occurs. In this condition the weld metal rolls and forms an
    angle less than 90 degrees.

    RECAP

    What are the different types of Butt joint?


    ______________________________________________________________________________
    ______________________________________________________________________________
    ______________________________________________________________________________
    _____________________________________________________________________________
    LESSON

    What is Welding Defects?

    Welding Defects -can be defined as the irregularities formed in the given weld metal
    due to wrong welding process or incorrect welding patterns, etc. The defect may
    differ from the desired weld bead shape, size, and intended quality. Welding defects
    may occur either outside or inside the weld metal. Some of the defects may be
    allowed if the defects are under permissible limits but other defects such as cracks
    are never accepted.

    Types

    Welding defects can be classified into two types as external and internal defects:

    External Welding Defects: Internal Welding Defects:


    1.WeldCrack 1. Slag Inclusion
    2. Undercut 2. Incomplete Fusion
    3. Spatter 3. Necklace cracking
    4. Porosity 4. Incompletely filled groove or
    5. Overlap Incomplete penetration
    6. Crater
    External Welding Defects

    1. Weld Crack
    This is the most unwanted defect of all the other
    welding defects. Welding cracks can be present at the
    surface, inside of the weld material or at the heat
    affected zones.

    2. Undercut - When the base of metal melts away


    from the weld zone, then a groove is formed in the
    shape of a notch, then this type of defect is known
    as Undercut. It reduces the fatigue strength of the
    joint.

    3. Spatter- When some metal drops are expelled


    from the weld and remain stuck to the surface,
    then this defect is known as Spatter.

    4. Porosity- Porosity is the condition in which the


    gas or small bubbles gets trapped in the welded
    zone.

    5. Overlap- When the weld face extends beyond the


    weld toe, then this defect occurs. In this condition
    the weld metal rolls and forms an angle less than
    90 degrees.

    6. Crater - It occurs when the crater is not filled before the arc is broken, which
    causes the outer edges to cool faster than the crater. This causes a stress and then
    crack is formed.

    Internal Welding Defects


    1. Slag Inclusion- If there is any slag in the
    weld, then it affects the toughness and metal
    weld ability of the given material. This
    decreases the structural performance of the
    weld material. Slag is formed on the surface of
    the weld or between the welding turns.

    2. Incomplete Fusion - Incomplete fusion


    occurs when the welder does not accurately
    weld the material and the metal pre solidifies
    which leads to a gap which is not filled with
    the molten metal.

    3. Necklace Cracking

    It occurs in the use of electron beam welding where the weld does not penetrate
    properly. Therefore, the molten metal does not flow into the cavity and results in a
    cracking known as “Necklace Cracking”.

    4. Incompletely Filled Groove or Incomplete


    Penetration - These defects occur only in the
    butt welds where the groove of the metal is
    not filled completely. It is also called as
    incomplete penetration defect.
    https://www.theweldingmaster.com/

    n Alloy Steels
    ACTIVITIES

    ACTIVITY NO.1:

    Directions: Identify the following welding defects by writing the name below the
    picture. Write your answer on the spaces provided.

    1. 5.

    2. 6.

    3. 7.

    4 8.
    ACTIVITY NO.1

    Directions: Enumerate the different welding defects by writing the name on the
    diagram below. Write your answer on the spaces provided.

    WELD DEFECTS

    External Weld Defects Internal weld defects

    WRAP–UP

    Today you have learned many things about the different Methods of Weld
    Testing, now in paragraph form summarize what you have learned.

    What is the meaning of Weld Defects?


    ___________________________________________________________________________
    ____________________________________________________________________
    __________________________________________________________________________________
    __________________________________________________________________________________
    VALUING
    Now that you’ve learned the meaning and different types Weld Defects.
    Write your thoughts in paragraphs below:

    1. What is the importance of knowing different types of Weld Defects in


    Welding?
    __________________________________________________________________________________
    __________________________________________________________________________________
    _________________________________________________________________________________.

    POSTTEST
    Directions: Encircle the letter of the correct answer in every items.
    1. What is the irregularities formed in the given weld metal due to wrong welding
    process or incorrect welding patterns?
    a. Weld defects
    b. Weld Crack
    c. Undercut
    d. Spatter

    2. What is This is the most unwanted defect of all the other welding defects?
    a. Weld defects
    b. Weld Crack
    c. Undercut
    d. Spatter

    3. What is this weld defect a characterized by some metal drops are expelled from
    the weld and remain stuck to the surface?
    a. Weld defects
    b. Weld Crack
    c. Undercut
    d. Spatter

    4. What is the condition in which the gas or small bubbles gets trapped in the
    welded zone?
    a. Spatter
    b. Porosity
    c. Overlap
    d. Incomplete Fusion

    5. What is this defect that occurs when the welder does not accurately weld the
    material and the metal pre solidifies which leads to a gap which is not filled with
    the molten metal?
    a. Spatter
    b. Porosity
    c. Overlap
    d. Incomplete Fusion
    header.png
    https://www.fastenal.com/content/merch_rules/images/fcom/headers/73-
    reserved
    https://weldguru.com/oxy-fuel-cutting/,© 2006 - 2020 WeldGuru.com - All rights
    Deped NCR Shielded Metal Arc Welding Module 1 series 2019
    R E F E R E N CE S
    PRETEST RECAP POSTTEST
    1. D Knowing the causes and prevention 1. A
    2. C may help the students/welder 2. B
    3. E avoid mistakes and performed good weld. 3. D
    4. B 4. B
    5. A 5. D
    ACTIVITY NO. 1 ACTIVITY NO. 2
    1. Spatter External Weld Defects Internal Weld Defects
    2. Slag inclusion 1. Weld Cracks 1. Slag Inclusion
    3. Porosity 2. Undercut 2. Incomplete Fusion
    4. Incomplete Penetration 2. Spatter 3. Necklace
    5. Incomplete Fusion 4. Porosity 4. Incomplete Penetration
    6. Cracks 5. Overlap
    7. Overlap 6. Crater
    8. Undercut
    KEY TO CORRECTION

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