Destructive Examination

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Destructive Examination Testing
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Destructive Examination

• Destructive Examination renders the weld or
  material unfit for further service.

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Common methods used in Destructive Examination

• Bend testing
• Tensile testing
• Impact testing
• Hardness testing
• Chemical analysis
• Hydrostatic testing to destruction
• Peel testing
• Spark testing

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Bend Testing

• Bend test samples are referred to as Test
  Coupons
• The most common bend tests are
• Guided face and root bend testing
• Guided side bend testing
• Longitudinal root and side bend testing
• Fillet weld bend testing
• Unguided bend testing

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Bend Testing Sample Removal
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Bend Testing Sample Preparation
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Face Bend Testing
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Root Bend Testing
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Side Bend Testing
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Longitudinal Face Bend Testing
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Longitudinal Root Bend Testing
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Fillet Bend Testing
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Pipe Fillet Bend Testing
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Tensile Strength Testing

• Tensile is a test in which a prepared sample is
  pulled until the sample breaks.
• Test Measurements are recorded in PSI (Pounds
  per Square Inch) E7018 70,000 PSI Tensile
• Test samples called Tensile Bolts can reveal a
  welds Tensile strength, Elastic limit, Yield
  point, and Ductility.

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Tensile Strength Testing

• The Elastic Limit of metal is the stress (load)
  it can withstand and still return to the original
  length after the load is released.
• Yield Strength occurs when the test sample
  stretches however will not return to its original
  length.
• Ductility is the ability of a metal to stretch or
  elongate before it breaks.

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Tensile Testing Strength Graph
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Impact Testing

• An Impact tester uses a heavy pendulum that is
  able to measure the amount of force required to
  shear or fracture a test sample taken from welds
  Heat Affected Zone (HAZ)
• Impact testing may be performed using either the
  Izod or Charpy method. (Both methods are similar)

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Impact Testing

• A Charpy or Izod test measures the welds ability
  to withstand an Impact force.
• Low Charpy test readings indicate brittle weld
  metal
• Higher Charpy readings indicate the samples
  toughness.

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Hardness testing

• Hardness may be defined as the resistance to
  permanent indentation.
• Three common hardness measuring tests are
• Rockwell test
• Scleroscope test
• Brinell
• Microhardness test

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Hardness testing

• The Rockwell testing machine operates somewhat
  like a press, using a indenter to penetrate the
  surface of the test sample.
• The depth of the indentation determines the
  materials hardness on a scale of 0-100

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Hardness testing

• The Sceleroscpoe testing machine measures the
  amount bounce that a diamond tip hammer
  rebounds off the test sample after being dropped.
• The Brinell method presses the indenter into a
  sample for a given period of time.
• The ability for the sample to resist indentation
  determines hardness.

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Hardness testing

• Microhardness testers allow you to measure a
  materials hardness while leaving the least amount
  of damage possible on the metals surface.
• After the indenter is used a powerful microscope
  is used to determine the the amount of
  indentation into the components surface.

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Chemical Analysis

• Chemical analysis is used in metallurgical
  laboratories to determine the metals grain and
  crystalline structures.
• Samples are then place under a high power
  microscope to view the results.
• This is referred to as Metalography

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Hydrostatic Testing to Destruction

• Pressure testing or leak testing can be performed
  with either gasses or liquids.
• When this pressure exceeds the limitations of the
  structures design it will rupture under force.
• This rupture will allow engineers to understand
  the welds weakest areas.

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Peel testing

• Lap joints may be tested to destruction using a
  Peel test.
• Peel testing is most commonly used to check the
  strength of resistance spot welds or stud weld
• Spot weld peel tests are considered successful
  when the spot weld nugget is torn out of the test
  sample pieces in tact.

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Spark Testing

• The shape and characteristic of sparks created
  when metal is ground will help determine its
  properties.
• IE carbon steel , mild steel.

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Quiz time

• Which of the following is a destructive test ?
• A magnet particle
• B tensile testing
• C die penetrate testing
• D ultrasonic testing

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Quiz time

• The _______ type hardness test leaves the least
  amount of damage on the metals surface.
• A Rockwell
• B Brinell
• C Scleroscope
• D Microhardness

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Quiz time

• When a metal stretches, but dose not break under
  a certain load, this point is called the
  _________ Point.
• A yield
• B tensile
• C stretch
• D ultimate strength

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Quiz time

• Ductility is the ability of a metal to ________
  before it breaks.
• A Bend
• B Stretch or elongate
• C Be forged
• D Be indented

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Quiz time

• A Charpy test measures a welds ability to
  withstand _________ force.
• A Impact
• B Bending
• C Penetrating
• D Stretching

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Quiz time

• Hardness may be defined as the resistance to
  __________?
• Indentation

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Modern WeldingYork County School of Technology