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Questions and Answers
What does the Rockwell hardness tester measure?
What does the Rockwell hardness tester measure?
- Size of the indentation
- Resistance to permanent deformation
- Depth of penetration under load (correct)
- Tensile strength
What is the designation for Brinell hardness value?
What is the designation for Brinell hardness value?
- HRC
- HRB
- HB (correct)
- HV
Which hardness test allows testing of welds with small indentation size and easy location of specific regions?
Which hardness test allows testing of welds with small indentation size and easy location of specific regions?
- Vickers hardness test (correct)
- Rockwell hardness test
- Brinell hardness test
- None of the above
What is the limitation of Brinell and Vickers tests?
What is the limitation of Brinell and Vickers tests?
What is the distance requirement between each indentation in Vickers test?
What is the distance requirement between each indentation in Vickers test?
What does hardness testing assess?
What does hardness testing assess?
What is the relationship between hardness and tensile strength of steel?
What is the relationship between hardness and tensile strength of steel?
Which scale is commonly used for testing welds in Rockwell hardness test?
Which scale is commonly used for testing welds in Rockwell hardness test?
What does the Vickers hardness number represent?
What does the Vickers hardness number represent?
What is the purpose of the side-bend specimen test?
What is the purpose of the side-bend specimen test?
What load range does the Vickers hardness test use?
What load range does the Vickers hardness test use?
What is the primary use of the all-weld-metal tensile test specimen?
What is the primary use of the all-weld-metal tensile test specimen?
How is the ultimate strength of the transverse weld test specimen determined?
How is the ultimate strength of the transverse weld test specimen determined?
What is the purpose of the guided bend test?
What is the purpose of the guided bend test?
Why is a larger radius required for bending higher strength steels?
Why is a larger radius required for bending higher strength steels?
What precaution must be taken in the preparation of bend samples?
What precaution must be taken in the preparation of bend samples?
What are the different types of guided bend tests?
What are the different types of guided bend tests?
Why are side-bends chosen for material over 10 mm?
Why are side-bends chosen for material over 10 mm?
What does the face-bend test reveal?
What does the face-bend test reveal?
What is the diameter of the all-weld-metal tensile test specimen?
What is the diameter of the all-weld-metal tensile test specimen?
What are the two commonly used tensile testing specimens?
What are the two commonly used tensile testing specimens?
What is the cross-sectional area of the all-weld-metal tensile specimen?
What is the cross-sectional area of the all-weld-metal tensile specimen?
What is the purpose of the transverse weld test specimen?
What is the purpose of the transverse weld test specimen?
What is the definition of quality in welding?
What is the definition of quality in welding?
What is the difference between a discontinuity and a defect in welding?
What is the difference between a discontinuity and a defect in welding?
What is the purpose of nondestructive testing (NDT) in welding?
What is the purpose of nondestructive testing (NDT) in welding?
What mechanical properties can be determined using tensile testing in welding?
What mechanical properties can be determined using tensile testing in welding?
What is the definition of stress in a material?
What is the definition of stress in a material?
What happens during elastic behavior of a material?
What happens during elastic behavior of a material?
What is the yield stress in welding?
What is the yield stress in welding?
What do different stress-strain curves in metals indicate?
What do different stress-strain curves in metals indicate?
What is the purpose of tensile tests in welding?
What is the purpose of tensile tests in welding?
What machines are used to carry out tensile tests in welding?
What machines are used to carry out tensile tests in welding?
Why is understanding quality, discontinuity, and testing methods crucial in welding?
Why is understanding quality, discontinuity, and testing methods crucial in welding?
What is the formula for calculating Vickers hardness number (HV)?
What is the formula for calculating Vickers hardness number (HV)?
Which type of hardness test can be applied to survey the hardness of relatively small areas such as sections of welds and heat-affected zones?
Which type of hardness test can be applied to survey the hardness of relatively small areas such as sections of welds and heat-affected zones?
Which hardness testing method can only be used for obtaining hardness values over a relatively large area such as the face of a weld?
Which hardness testing method can only be used for obtaining hardness values over a relatively large area such as the face of a weld?
What does the Charpy impact test measure?
What does the Charpy impact test measure?
What units are used to measure the energy absorbed in a Charpy impact test?
What units are used to measure the energy absorbed in a Charpy impact test?
What type of specimen is commonly used for Charpy impact testing?
What type of specimen is commonly used for Charpy impact testing?
What does the transition temperature in impact testing indicate?
What does the transition temperature in impact testing indicate?
What can lead to misleading results in impact testing?
What can lead to misleading results in impact testing?
What is the purpose of impact tests in the classification of an electrode?
What is the purpose of impact tests in the classification of an electrode?
What are the two types of hardness testing methods mentioned in the text?
What are the two types of hardness testing methods mentioned in the text?
What information do hardness traverses across a weld provide?
What information do hardness traverses across a weld provide?
What is the purpose of micro or macro hardness testing in welds?
What is the purpose of micro or macro hardness testing in welds?
What is the significance of using a diamond or large steel ball in hardness testing?
What is the significance of using a diamond or large steel ball in hardness testing?
What can different hardness testing methods require in terms of sample thickness?
What can different hardness testing methods require in terms of sample thickness?
What is the primary use of hardness testing methods in welded structures?
What is the primary use of hardness testing methods in welded structures?
What is the mode of transfer for the welding process mentioned in the text?
What is the mode of transfer for the welding process mentioned in the text?
What is the standard mentioned for the single electrode mechanized process?
What is the standard mentioned for the single electrode mechanized process?
What is the purpose of checking the joint preparation and fit-up in welding?
What is the purpose of checking the joint preparation and fit-up in welding?
Which item should be checked to ensure that all the required welds have been made?
Which item should be checked to ensure that all the required welds have been made?
What is the primary use of visual inspection after welding?
What is the primary use of visual inspection after welding?
What is the purpose of reviewing welder qualifications?
What is the purpose of reviewing welder qualifications?
What should be monitored, if required, during welding?
What should be monitored, if required, during welding?
What is the purpose of measuring fillet weld sizes?
What is the purpose of measuring fillet weld sizes?
What is the purpose of ensuring that electrodes are stored and handled correctly?
What is the purpose of ensuring that electrodes are stored and handled correctly?
What is the purpose of checking for the presence of moisture, scale, slag, oil, grease, paint, etc. on the joint surface?
What is the purpose of checking for the presence of moisture, scale, slag, oil, grease, paint, etc. on the joint surface?
What is the purpose of identifying the weld size requirements?
What is the purpose of identifying the weld size requirements?
What is the primary use of visual inspection during welding?
What is the primary use of visual inspection during welding?
What is the purpose of the nick-break test in weld inspection?
What is the purpose of the nick-break test in weld inspection?
Where are the impact specimens located for a 20 mm thick test plate?
Where are the impact specimens located for a 20 mm thick test plate?
What is the basis for all weld examination methods?
What is the basis for all weld examination methods?
What is the purpose of the fillet weld break test?
What is the purpose of the fillet weld break test?
What does the nick-break test evaluate in a region of the welded joint?
What does the nick-break test evaluate in a region of the welded joint?
What is examined when macroscopic examination is performed?
What is examined when macroscopic examination is performed?
When should visual inspection be performed in the welding process?
When should visual inspection be performed in the welding process?
What is the purpose of testing the heat-affected zone in weld inspection?
What is the purpose of testing the heat-affected zone in weld inspection?
What is the purpose of the macroscopic examination in weld inspection?
What is the purpose of the macroscopic examination in weld inspection?
What is the purpose of the fillet weld break test in weld inspection?
What is the purpose of the fillet weld break test in weld inspection?
What is the purpose of the nick-break test in weld inspection?
What is the purpose of the nick-break test in weld inspection?
What is the basis for all weld examination methods?
What is the basis for all weld examination methods?
What tools are used for traditional visual inspection of weld surface discontinuities?
What tools are used for traditional visual inspection of weld surface discontinuities?
What are examples of nondestructive examination methods mentioned in the text?
What are examples of nondestructive examination methods mentioned in the text?
Why is visual inspection commonly used in production?
Why is visual inspection commonly used in production?
What are the main tools used to facilitate visual inspection?
What are the main tools used to facilitate visual inspection?
What type of discontinuities can the AC yoke be used to detect?
What type of discontinuities can the AC yoke be used to detect?
Why is the use of prods prohibited by certain codes in magnetic particle inspection?
Why is the use of prods prohibited by certain codes in magnetic particle inspection?
Which materials cannot be examined using magnetic particle inspection?
Which materials cannot be examined using magnetic particle inspection?
What is the primary purpose of radiographic inspection (RT) in welds?
What is the primary purpose of radiographic inspection (RT) in welds?
What is the difference between X-radiography and gamma radiography?
What is the difference between X-radiography and gamma radiography?
What is the danger associated with ionizing radiation used in radiography?
What is the danger associated with ionizing radiation used in radiography?
What determines the appearance of light or dark shadows on the radiographic film?
What determines the appearance of light or dark shadows on the radiographic film?
What is the primary use of the dry powder method in radiographic inspection?
What is the primary use of the dry powder method in radiographic inspection?
What is the primary use of the wet fluorescent method in radiographic inspection?
What is the primary use of the wet fluorescent method in radiographic inspection?
What is the main limitation of radiography in the inspection of welds?
What is the main limitation of radiography in the inspection of welds?
What is the primary purpose of establishing a safe zone and posting warning signs during radiography?
What is the primary purpose of establishing a safe zone and posting warning signs during radiography?
What is the significance of evaluating the shape, density, and location of the images created by voids and inclusions on radiographic film?
What is the significance of evaluating the shape, density, and location of the images created by voids and inclusions on radiographic film?
What does liquid penetrant inspection measure in welding?
What does liquid penetrant inspection measure in welding?
What is the purpose of magnetic particle inspection in welding?
What is the purpose of magnetic particle inspection in welding?
What is the difference between visible dye and fluorescent dye penetrant?
What is the difference between visible dye and fluorescent dye penetrant?
What is the main limitation of magnetic particle inspection?
What is the main limitation of magnetic particle inspection?
What is the primary use of fluorescent penetrant testing?
What is the primary use of fluorescent penetrant testing?
What is the purpose of applying a developer in liquid penetrant inspection?
What is the purpose of applying a developer in liquid penetrant inspection?
What is the main advantage of liquid penetrant inspection in welding?
What is the main advantage of liquid penetrant inspection in welding?
How is the magnetic field induced in magnetic particle inspection?
How is the magnetic field induced in magnetic particle inspection?
When is direct current used in magnetic particle inspection?
When is direct current used in magnetic particle inspection?
What is the purpose of the ultraviolet or black light in fluorescent penetrant testing?
What is the purpose of the ultraviolet or black light in fluorescent penetrant testing?
Which type of penetrant testing is effective for detecting leaks in welded joints in tanks and containers?
Which type of penetrant testing is effective for detecting leaks in welded joints in tanks and containers?
What is the main advantage of magnetic particle inspection over liquid penetrant inspection?
What is the main advantage of magnetic particle inspection over liquid penetrant inspection?
Study Notes
Quality Control and Inspection Methods in Welding
- Quality is defined as the degree to which inherent characteristics fulfill requirements, with the concept of meeting needs, requirements, and expectations being a common element.
- A weld's quality is defined as its ability to perform reliably throughout its intended service life, and is influenced by workmanship, which depends on the skill of the welder and the experience of the supervisor.
- Discontinuity refers to an interruption of the typical structure of a material, while a defect is a discontinuity that renders a part unable to meet minimum acceptance standards or specifications.
- Inspection test methods include destructive testing, which involves destroying the completed weld to evaluate its characteristics, and nondestructive testing (NDT), where a component is evaluated without damaging it.
- Tensile testing is used to determine mechanical properties such as yield strength, ultimate strength, and ductility of materials in welding.
- Stress in a material is the intensity of internal forces resisting an external force, while strain measures the change in dimensions due to applied load.
- Elastic behavior occurs when a material returns to its original dimensions after stress is removed, while plastic deformation results in permanent strain.
- The yield stress is the stress at which a given permanent set is recorded, and it is usually defined as the stress at which a 0.2% permanent set is observed.
- Different metals exhibit different stress-strain curves, with some showing a gradual change from elastic to plastic behavior, while others show an abrupt change.
- Tensile tests involve loading a standard test specimen in tension until it fails, and can determine mechanical properties significant in welding, such as yield strength, ultimate strength, and ductility.
- Special machines, mechanical, and hydraulic, are used to carry out tensile tests, exerting the necessary force in a controlled manner.
- Understanding the concepts of quality, discontinuity, and testing methods is crucial in maintaining welding standards and ensuring the reliability of welded structures.
Hardness Testing Methods and Impact Test in Welded Structures
- Hardness testing methods include using a diamond or large steel ball and applying small or large loads
- Different methods require measuring indent or not, and may require thick or thin samples
- Micro or macro hardness testing is used, with preference for certain regions in welds and limitations on welds
- Hardness traverses across a weld provide information on as-welded and stress relieved conditions
- Impact tests are crucial in identifying materials' behavior under notches or cracks, especially in welded structures
- Charpy impact test is commonly used to measure toughness by recording energy absorbed when a notched specimen is broken
- The value of energy absorbed is measured in joules or foot-pounds
- Charpy V-notch (CVN) specimen with specific dimensions is commonly used for testing
- Steel's brittleness at low temperatures is revealed through impact tests at different temperatures
- The transition temperature, at which a certain energy is reached, is used to compare the toughness of materials
- Misleading results can occur if the impact test specimens are not machined from the right location or if the notch is oriented incorrectly
- Impact tests are required as part of the classification of an electrode, and the specimens are machined from the same test weld as the tensile specimens
Weld Inspection and Testing Methods
- The test plate is 20 mm thick and the impact specimens are located mid-thickness
- Notch is placed perpendicular to the plate surface on the centreline of the weld
- Testing the heat-affected zone can be troublesome due to its narrow width and slope
- Nick-break test is used for revealing internal weld discontinuities
- Fractured surface is examined for discontinuities such as porosity, slag inclusions, incomplete penetration, and incomplete fusion
- The nick-break test is required in codes to evaluate the entire surface area within a region of the welded joint
- The fillet weld break test is used to evaluate the general quality of the weld
- A force is applied to the back side of the welded T-joint until the fillet weld fractures
- Macroscopic examination involves cutting through the finished weld to examine its cross-section
- Visual inspection is the basis for all weld examination methods
- Visual inspection is fast, inexpensive, and is performed before, during, and after welding
- Before welding starts, weld preparations and fit-up dimensions must be verified to comply with requirements
Non-Destructive Testing Methods in Welding
- Liquid penetrant inspection measures undercut, excess groove weld height, fillet weld leg length, theoretical fillet weld throat, and permissible fillet weld tolerance for convexity and concavity.
- Liquid penetrant inspection, also known as penetrant testing, is used to locate cracks, porosity, laps, and folds that are open to the surface.
- The method involves preparing the surface, applying the penetrant, allowing it to dwell, removing excess penetrant, applying a developer, and visually examining the indication.
- Liquid penetrant inspection is simple, inexpensive, and does not typically require complex equipment.
- There are two basic types of penetrant: visible dye and fluorescent dye, with the latter requiring ultraviolet or black light for viewing.
- Fluorescent penetrant testing is effective for detecting leaks in welded joints in tanks and containers.
- Magnetic particle inspection is used to detect surface and near-surface discontinuities in ferromagnetic materials.
- The method involves inducing a magnetic field into the part and dusting it with fine, colored, iron powder, which collects at the poles created by discontinuities.
- Magnetic particle inspection is effective for detecting fine cracking that comes to the surface but limited in detecting isolated indications such as porosity.
- The magnetic field can be induced using the AC/DC yoke method or by placing the part inside a coil to produce a longitudinal field between the poles.
- Direct current is used to detect surface discontinuities and linear discontinuities near the surface, while alternating current is used for discontinuities breaking the surface of the weld.
- Both liquid penetrant inspection and magnetic particle inspection are widely used non-destructive testing methods in the welding industry.
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Test your knowledge of quality control and inspection methods in welding with this quiz. Explore concepts such as weld quality, discontinuity, inspection test methods, tensile testing, stress and strain, and mechanical properties. Enhance your understanding of maintaining welding standards and ensuring the reliability of welded structures.
