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Ghana National Certificate II Welding and Fabrication preparation study materials
Ghana National Certificate II Welding and Fabrication preparation study resources

Ghana National Certificate II Welding and Fabrication preparation practice questions

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Question 1Construction planning, safe boundaries, inspections and controlled changes

Why is it critical to wear safety glasses under a welding helmet during welding operations?

  1. To protect the eyes from flying slag and spatter when the helmet is flipped up. Correct answer.
  2. To double the shade value of the welding helmet's filter lens.
  3. To prevent the helmet from sliding off the welder's head.
  4. To filter out high-frequency sound waves from the arc.

Explanation

Safety glasses must be worn under a welding helmet because slag, sparks, and debris can still fly behind the shield, especially when the welder flips up the helmet to inspect or chip the weld bead. They provide continuous lateral and frontal physical impact protection. They do not increase the light-reduction shade value, prevent the helmet from slipping, or filter sound waves.

Question 2Construction planning, safe boundaries, inspections and controlled changes

What health hazard is caused by inhaling the white fumes generated when welding galvanized steel, and how is it prevented?

  1. Zinc fume fever; prevented by local exhaust ventilation and respirator use. Correct answer.
  2. Silicosis; prevented by wearing leather aprons and safety boots.
  3. Asbestosis; prevented by using water-cooled torches.
  4. Carbon monoxide poisoning; prevented by using carbon dioxide shielding gas.

Explanation

Galvanized steel is coated with zinc. Welding it vaporizes the zinc coating, producing zinc oxide fumes which can cause 'zinc fume fever' or 'metal fume fever' (symptoms include chills, fever, nausea, and muscle aches). Prevention requires proper ventilation, source extraction, and wearing a particulate respirator. Silicosis is caused by silica dust, asbestosis by asbestos fibers, and CO poisoning by incomplete combustion.

Question 3Construction planning, safe boundaries, inspections and controlled changes

What is the primary function of local exhaust ventilation (LEV) systems in a vocational welding workshop?

  1. To capture and remove welding fumes and gases at their source before they reach the welder's breathing zone. Correct answer.
  2. To cool down the welding workpiece during high-current operations.
  3. To provide a clean supply of pure oxygen to support the arc.
  4. To blow away shielding gases to speed up weld solidification.

Explanation

Local exhaust ventilation (LEV) utilizes extraction hoods positioned close to the weld pool to capture toxic welding fumes and gases directly at the source, preventing them from mixing with the general workshop air and entering the welder's breathing zone. It is not designed to cool metal, supply oxygen (which would be a fire hazard), or disrupt shielding gases.

Question 4Construction planning, safe boundaries, inspections and controlled changes

If a fellow student is in contact with an active, live electrical wire in the welding shop, what is the first action you should take?

  1. Turn off or isolate the main power source immediately before touching the victim. Correct answer.
  2. Grab the victim's arms and pull them away from the wire as fast as possible.
  3. Throw cold water over the victim to disrupt the electrical current.
  4. Wrap a wet rag around the wire to insulate it from the ground.

Explanation

The absolute first step is to isolate the electrical source (turn off the switchboard breaker or unplug the machine) to ensure the rescuer does not also become energized by contact. Touching the victim while they are still in the live circuit will result in the rescuer being shocked. Water conductive properties would make throw-water extremely dangerous, and a wet rag conducts electricity.

Question 5Construction planning, safe boundaries, inspections and controlled changes

What is the extreme danger associated with using oil or grease to lubricate the threads of an oxygen cylinder regulator?

  1. High-pressure oxygen reacts violently with hydrocarbons (oil/grease), causing spontaneous combustion or explosion. Correct answer.
  2. The oil will contaminate the gas, causing severe weld porosity.
  3. The grease will clog the regulator diaphragm, preventing gas flow.
  4. Oil causes the brass threads to corrode and seize permanently.

Explanation

High-pressure oxygen must never come into contact with oils, greases, or other hydrocarbons. In a pressurized oxygen environment, these organic compounds can ignite spontaneously and burn with explosive violence. Regulators must be kept completely free of oil, grease, or flammable substances, and thread compounds should never be used.

Question 6Construction planning, safe boundaries, inspections and controlled changes

What is the medical term for the painful eye condition caused by exposure of unprotected eyes to ultraviolet (UV) rays from a welding arc?

  1. Photokeratitis (arc eye) Correct answer.
  2. Glaucoma
  3. Cataracts
  4. Astigmatism

Explanation

Photokeratitis, commonly referred to as 'arc eye' or 'flash burn', is a painful inflammation of the cornea caused by exposure to ultraviolet (UV) radiation emitted by electric welding arcs. The symptoms include a gritty feeling in the eyes, watering, sensitivity to light, and redness, which typically develop several hours after exposure. Glaucoma and cataracts are chronic eye diseases, and astigmatism is a refractive error.

Question 7Welding processes, joint preparation and controlled heat input

In the AWS classification system for manual metal arc welding (SMAW) electrodes, what does the letter 'E' stand for?

  1. Electrode Correct answer.
  2. Engineered
  3. Electricity
  4. Extruded flux

Explanation

In AWS electrode designations (like E6013), the letter 'E' stands for 'electrode', indicating that it is a consumable electrical conductor that carries current and melts to supply filler metal to the joint. The subsequent digits specify tensile strength, welding position, and flux coating characteristics. It does not mean engineered, electricity, or extruded flux.

Question 8Welding processes, joint preparation and controlled heat input

What is represented by the first two digits (e.g., '70') of the AWS classification E7018 welding electrode?

  1. The minimum tensile strength of the deposited weld metal in thousands of pounds per square inch (kpsi). Correct answer.
  2. The maximum current carrying capacity in amperes.
  3. The percentage of iron powder contained in the flux coating.
  4. The minimum preheating temperature of the base metal in degrees Celsius.

Explanation

The first two digits (or three digits if it is a five-digit code like E11018) indicate the minimum tensile strength of the weld deposit. For E7018, '70' indicates that the weld metal has a minimum tensile strength of 70,000 pounds per square inch (psi) or 70 kpsi. This ensures the weld joint can match or exceed the strength requirements of the structural base metal.

Question 9Welding processes, joint preparation and controlled heat input

Which welding positions are permitted when using an AWS E6013 electrode, as indicated by the third digit in its code?

  1. All positions (flat, horizontal, vertical, and overhead) Correct answer.
  2. Flat and horizontal fillet positions only
  3. Flat position only
  4. Vertical-down position only

Explanation

In the AWS four-digit electrode classification, the third digit represents the allowable welding positions. The digit '1' indicates that the electrode is suitable for all positions (flat, horizontal, vertical, and overhead). A digit '2' would restrict use to flat and horizontal fillet welds, and '4' would indicate suitability for vertical-down welding.

Question 10Welding processes, joint preparation and controlled heat input

What characteristics does the number '8' represent in the last digit of the AWS E7018 electrode code?

  1. Low-hydrogen potassium coating with iron powder, compatible with AC or DCEP. Correct answer.
  2. High cellulose sodium coating, compatible with DCEN only.
  3. High titania potassium (rutile) coating, compatible with AC only.
  4. Iron oxide sodium coating, compatible with DCEP only.

Explanation

The last digit '8' in E7018 designates a low-hydrogen potassium coating that contains 25% to 40% iron powder. This coating provides high deposition rates, low moisture pickup to prevent cracking, and works well on either alternating current (AC) or direct current electrode positive (DCEP). High cellulose coatings end in '0' or '1', and rutile coatings end in '2' or '3'.

Question 11Welding processes, joint preparation and controlled heat input

What is the primary chemical constituent in the flux coating of an E6013 electrode, which gives it its smooth arc characteristics?

  1. Rutile (Titanium Dioxide) Correct answer.
  2. Cellulose (Wood flour)
  3. Calcium carbonate (Lime)
  4. Iron powder only

Explanation

An E6013 electrode is classified as a rutile-type electrode because its flux coating is high in titanium dioxide (rutile). This formulation creates a very stable, quiet arc, low spatter, and an easily removable, glass-like slag, making it popular for general sheet metal and structural fabrication. Cellulosic coatings (E6010) use wood pulp, and low-hydrogen coatings (E7018) use lime (calcium carbonate).

Question 12Welding processes, joint preparation and controlled heat input

Why must low-hydrogen electrodes like E7018 be stored in specialized holding ovens after their hermetically sealed containers are opened?

  1. To prevent the flux coating from absorbing moisture from the air, which causes hydrogen cracking in high-strength steels. Correct answer.
  2. To preheat the core wire so it ignites the arc at lower welding voltages.
  3. To dry out toxic chemicals in the flux before they burn and release fumes.
  4. To melt the iron powder slightly to improve its binding with the flux.

Explanation

Low-hydrogen electrodes (E7018) are highly hygroscopic, meaning they readily absorb moisture from the atmosphere. If moisture is absorbed, the arc heat dissociates water into hydrogen, which dissolves into the weld pool and can lead to porosity and hydrogen-induced cracking (cold cracking). Storing them in ovens at 120-150°C keeps them dry and maintains their low-hydrogen properties.

Question 13Welding processes, joint preparation and controlled heat input

Which of the following defects is most likely to occur in structural steel welds if wet or moisture-contaminated E7018 electrodes are used?

  1. Porosity and hydrogen-induced underbead cracking Correct answer.
  2. Slag inclusions at the weld cap
  3. Excessive root penetration
  4. Tungsten contamination of the weld pool

Explanation

Moisture in the electrode coating introduces hydrogen and oxygen into the welding arc. The hydrogen dissolved in the weld pool causes underbead (cold) cracking as the weld cools, while escaping gas bubbles that fail to exit the freezing metal result in porosity. Slag inclusions are caused by poor manipulation, excessive root penetration by current settings, and tungsten contamination is unique to the GTAW (TIG) process.

Question 14Welding processes, joint preparation and controlled heat input

A supplied welding-machine rating defines60percent dutycycle over a10minute reference period at its stated current and conditions. Which listed interpretation matches?

  1. The percentage of a 10-minute period the machine can operate continuously at rated current without overheating. Correct answer.
  2. The ratio of welding time to chipping and cleaning time in a shift.
  3. The electrical efficiency rating of the transformer under full load.
  4. The lifespan of the machine before internal component maintenance is required.

Explanation

Duty cycle is a standardized rating based on a 10-minute cycle. A 60% duty cycle at 200 A means the machine can weld continuously at 200 A for 6 minutes out of every 10 minutes. The remaining 4 minutes must be spent idling with the cooling fan running to prevent thermal damage to the internal transformer or inverter coils.

Question 15Welding processes, joint preparation and controlled heat input

Why do manual welding processes like SMAW and GTAW require a Constant Current (CC) power source instead of a Constant Voltage (CV) power source?

  1. To keep the welding current relatively stable even when the welder's hand movements cause slight variations in arc length. Correct answer.
  2. To prevent the voltage from dropping when the electrode touches the plate.
  3. To allow the wire feeder to adjust its speed automatically.
  4. To ensure the welding machine consumes less grid electricity.

Explanation

In manual welding, it is impossible for a welder to maintain a perfectly constant arc length. A Constant Current (CC) power source has a drooping volt-ampere output curve, which ensures that minor changes in arc length (voltage) result in only negligible changes in welding current (amperage). This keeps the heat input and weld puddle size consistent. Constant Voltage (CV) is used for semi-automatic wire-fed processes.

Question 16Welding processes, joint preparation and controlled heat input

What is the phenomenon called when the welding arc is deflected from its intended path by magnetic forces during DC SMAW operations?

  1. Arc blow Correct answer.
  2. Backfire
  3. Magnetic decay
  4. Wandering current

Explanation

Arc blow is the deflection of a welding arc from its normal path due to magnetic disturbances. When welding with direct current (DC), the current flowing through the electrode and workpiece establishes magnetic fields. These fields can concentrate unevenly near corners or ends of joints, pulling or pushing the arc sideways. It does not occur with alternating current (AC) because the magnetic field reverses direction too rapidly.

Question 17Welding processes, joint preparation and controlled heat input

Which set of tools must a welder use to properly clean a manual metal arc weld bead between successive weld passes?

  1. Chipping hammer and wire brush Correct answer.
  2. Ball-peen hammer and cold chisel
  3. Angle grinder with a cutting disc only
  4. Wet rag and steel wool

Explanation

Successive weld passes require the complete removal of solidified slag to prevent 'slag inclusions'. The welder uses a chipping hammer to crack and flake off the brittle slag, followed by vigorous wire brushing to remove any remaining fine particles. Ball-peen hammers can dent the plate, cutting discs are for cutting rather than cleaning, and wet rags are dangerous due to rapid cooling and steam/shock risks.

Question 18Welding processes, joint preparation and controlled heat input

How does the selection of a larger electrode diameter affect the required welding current (amperage) in SMAW?

  1. It requires a higher welding current to melt the larger volume of metal. Correct answer.
  2. It requires a lower welding current to prevent the core wire from overheating.
  3. The current remains exactly the same; only the voltage must be increased.
  4. It requires alternating current (AC) only, rendering DC unusable.

Explanation

Larger diameter electrodes contain a higher mass of steel core wire and flux coating, requiring more heat energy to melt. Consequently, the welder must increase the current setting on the machine to maintain a stable arc and achieve proper penetration. For example, a 2.5 mm electrode is typically run at 60-90 A, whereas a 4.0 mm electrode requires 140-180 A.

Question 19Welding processes, joint preparation and controlled heat input

What is the primary operational benefit of using a cellulosic electrode (such as E6010) compared to a rutile electrode (such as E6013)?

  1. It provides deep weld penetration and a fast-freezing weld puddle, making it ideal for pipe root passes. Correct answer.
  2. It produces a highly aesthetic weld cap with virtually no spatter.
  3. It does not require slag removal between weld passes.
  4. It can weld thick steel without generating any toxic fumes.

Explanation

Cellulosic electrodes like E6010 have coatings containing organic wood pulp. When burned, they release a forceful gas jet that digs deeply into the steel, providing deep penetration. The slag is thin and freezes quickly, allowing the welder to control the weld puddle in out-of-position pipe welding. Rutile electrodes (E6013) produce a smoother arc and prettier finish but have shallow penetration and a slower-freezing slag.

Question 20Welding processes, joint preparation and controlled heat input

What is the alternative name for the Direct Current Electrode Positive (DCEP) welding current setup?

  1. Reverse polarity Correct answer.
  2. Straight polarity
  3. Alternating phase
  4. Open-circuit potential

Explanation

Direct Current Electrode Positive (DCEP) is widely known as 'reverse polarity'. In this configuration, the electrode holder is connected to the positive terminal of the power source, and the work lead is connected to the negative terminal. DCEN (Electrode Negative) is known as 'straight polarity'. AC is alternating phase, and open-circuit voltage is the voltage before the arc is struck.

Question 21Welding processes, joint preparation and controlled heat input

Which of the following is a primary function of the flux coating on an SMAW electrode during the welding process?

  1. To generate a shielding gas that protects the molten weld pool from oxygen and nitrogen in the atmosphere. Correct answer.
  2. To physically increase the diameter of the core wire to speed up welding.
  3. To act as a heat insulator to cool down the weld joint rapidly.
  4. To prevent the electrode holder from becoming electrically live.

Explanation

The primary function of the flux coating is to decompose under the arc's heat to generate a shielding gas cloud (such as carbon dioxide or hydrogen). This gas displaces the air, preventing oxygen and nitrogen from contaminating and weakening the molten weld metal. The flux also forms a slag layer that protects the cooling weld bead and contains deoxidizers to clean the weld pool. It does not insulate the holder or physically modify core wire diameter.

Question 22Weld imperfections, inspection evidence and repair control

What weld defect is characterized by a groove melted into the base metal adjacent to the weld toe that has not been filled with weld metal?

  1. Undercut Correct answer.
  2. Overlap
  3. Porosity
  4. Lack of penetration

Explanation

Undercut is a defect where a groove is melted into the base metal at the toe of the weld but is left unfilled by the weld metal. It is commonly caused by excessive current, an incorrect electrode angle, or a travel speed that is too fast. This creates a stress concentration point that can lead to premature structural failure. Overlap is excess weld metal flowing over the base metal without fusing, porosity is gas pockets, and lack of penetration is failing to reach the root.

Question 23Welding processes, joint preparation and controlled heat input

Which type of welding power source design is required for Gas Metal Arc Welding (GMAW) to maintain a stable arc length automatically?

  1. Constant Voltage (CV) Correct answer.
  2. Constant Current (CC)
  3. High Frequency AC Transformer
  4. Variable Resistance Generator

Explanation

GMAW utilizes a Constant Voltage (CV) power source. In CV welding, the welder sets the voltage and wire feed speed. The machine automatically adjusts the amperage output to melt the wire at the rate it is fed, maintaining a constant arc length. If the welder's hand moves closer or further, the current changes rapidly to burn back the wire to the pre-set voltage/arc length. CC is used for SMAW and GTAW.

Question 24Welding processes, joint preparation and controlled heat input

In Gas Tungsten Arc Welding (GTAW/TIG), what is the primary function of the shielding gas?

  1. To shield the hot tungsten electrode and the weld pool from atmospheric contamination. Correct answer.
  2. To react with the tungsten to generate filler metal.
  3. To cool the workpiece to prevent heat distortion.
  4. To add carbon to the weld pool to increase joint hardness.

Explanation

The primary function of the shielding gas in GTAW is to protect both the non-consumable tungsten electrode and the molten weld pool from oxygen, nitrogen, and hydrogen in the air. If the gas flow stops, the tungsten electrode will immediately oxidize, burn away, and contaminate the weld. Shielding gases must be strictly inert (like argon or helium) so they do not react with the weld metal.

Question 25Welding processes, joint preparation and controlled heat input

Which Gas Metal Arc Welding (GMAW) metal transfer mode is characterized by a low heat input and a rapid cycle of wire short-circuiting into the weld pool?

  1. Short-circuiting transfer Correct answer.
  2. Spray transfer
  3. Globular transfer
  4. Pulsed spray transfer

Explanation

Short-circuiting transfer (dip transfer) operates at lower voltages and currents. The wire electrode physically touches the weld pool, short-circuits, and melts off in a rapid cycle (50 to 250 times per second). This produces low heat input, making it ideal for thin sheet metals and out-of-position welding (vertical/overhead). Spray transfer requires high voltage and argon-rich gas, producing high heat and a continuous spray of fine droplets.

Question 26Welding processes, joint preparation and controlled heat input

Which of the following is a common cause of gas shielding loss, leading to porosity in a MIG weld bead?

  1. A drafty workspace blowing the gas away or spatter buildup inside the gas nozzle. Correct answer.
  2. Setting the wire feed speed too low.
  3. Using a copper contact tip that matches the wire size.
  4. Welding with DCEP polarity instead of DCEN.

Explanation

MIG and TIG welding rely on an external gas envelope to shield the weld. If there is a draft in the shop (above 8 km/h), the gas is blown away, exposing the weld pool. Spatter buildup inside the gas nozzle also disrupts the smooth, laminar flow of shielding gas, causing turbulence that draws in air. Contact tip wear or wire feed speed does not affect the gas flow directly.

Question 27Welding processes, joint preparation and controlled heat input

In the MIG wire classification 'ER70S-6', what does the letter 'S' represent?

  1. Solid wire Correct answer.
  2. Stainless steel
  3. Shielded core
  4. Strength rating

Explanation

In the AWS designation ER70S-6, 'E' stands for electrode, 'R' for rod, '70' for minimum tensile strength in kpsi (70,000 psi), 'S' for solid wire, and '6' refers to the chemical composition and deoxidizer levels (high silicon/manganese). Solid wires require external shielding gas, unlike flux-cored wires which are designated with a 'T' (tubular).

Question 28Welding processes, joint preparation and controlled heat input

What is a major process advantage of TIG (GTAW) welding compared to MIG (GMAW) welding?

  1. It allows precise control of heat input and produces high-quality, slag-free welds on thin and exotic metals. Correct answer.
  2. It has much higher metal deposition rates, speeding up structural plate welding.
  3. It is highly tolerant of rust, oil, and moisture on the base metal surface.
  4. It does not require any protective eye shield due to the low arc glare.

Explanation

GTAW provides separate control over the heat source (arc) and the addition of filler metal, allowing high precision. Because it utilizes an inert gas shield and non-consumable tungsten, it produces extremely clean, high-quality, and slag-free welds on stainless steel, aluminum, and thin sheets. MIG has higher deposition rates but less heat control, and TIG is highly sensitive to surface contaminants, requiring meticulous joint cleaning.

Question 29Welding processes, joint preparation and controlled heat input

Which welding process uses a non-consumable electrode?

  1. Gas Tungsten Arc Welding (GTAW) Correct answer.
  2. Manual Metal Arc Welding (MMAW)
  3. Gas Metal Arc Welding (GMAW)
  4. Flux-Cored Arc Welding (FCAW)

Explanation

Gas Tungsten Arc Welding (GTAW / TIG) uses a non-consumable tungsten electrode because tungsten has an extremely high melting point (~3422°C) and does not melt into the weld pool. The arc simply heats the base metal, and filler metal is added separately by hand. MMAW, GMAW, and FCAW all use consumable electrodes that melt to become the weld deposit.

Question 30Welding processes, joint preparation and controlled heat input

What is the term for the distance that the solid wire extends past the contact tip of a MIG gun during welding, which affects electrical resistance and preheating?

  1. Electrode extension (stick-out) Correct answer.
  2. Arc gap
  3. Gas nozzle recess
  4. Burn-back distance

Explanation

Electrode extension, commonly referred to as 'stick-out', is the distance between the end of the contact tip and the end of the wire electrode. This length of wire is preheated by its own electrical resistance before melting. A stick-out that is too long (over 15 mm) reduces welding current and weakens the shielding gas coverage, while a stick-out that is too short can fuse the wire to the contact tip.

Question 31Welding processes, joint preparation and controlled heat input

Which type of oxy-acetylene flame is characterized by a rounded, white inner cone and is used for welding most carbon steels?

  1. Neutral flame Correct answer.
  2. Oxidizing flame
  3. Carburizing (reducing) flame
  4. Saturated flame

Explanation

A neutral flame is adjusted by burning a 1-to-1 ratio of oxygen and acetylene. It has a distinct, well-defined, rounded inner cone that is white, surrounded by a light-blue outer envelope. Because it does not add carbon to or extract oxygen from the steel weld pool, it is the standard flame for welding carbon steels. Carburizing has excess acetylene, and oxidizing has excess oxygen.

Question 32Welding processes, joint preparation and controlled heat input

What is the critical difference between a torch 'backfire' and a torch 'flashback'?

  1. A backfire is a momentary recession of the flame accompanied by a pop; a flashback is a sustained flame recession back into the torch, hoses, and regulators. Correct answer.
  2. A backfire occurs only in oxygen hoses, while a flashback occurs only in acetylene hoses.
  3. A backfire is caused by high gas pressure, whereas a flashback is caused by running out of gas.
  4. A backfire is a safe operation indicator, while a flashback is a minor leak.

Explanation

A backfire is a momentary recession of the flame into the torch tip, usually causing a loud 'pop' sound before the flame either goes out or continues burning at the tip. A flashback is a highly dangerous condition where the flame burns back through the torch mixing chamber and travels into the hoses and regulators, which can cause hose rupture or cylinder explosion. Flashback arrestors are designed to stop this event.

Question 33Welding processes, joint preparation and controlled heat input

When setting up an oxy-fuel cutting torch, what gas is released when you depress the cutting oxygen lever?

  1. A high-pressure stream of pure oxygen, which oxidizes (burns) the preheated iron and blows it away. Correct answer.
  2. A mixture of acetylene and oxygen to start the melting action.
  3. Pure acetylene gas to cool down the slag.
  4. Compressed atmospheric air to sweep the kerf clean.

Explanation

Oxy-fuel cutting is a chemical oxidation (burning) process. The preheat flames heat the steel to its ignition temperature (~900°C, bright red). When the cutting lever is depressed, a jet of high-pressure pure oxygen is released. This oxygen reacts with the hot iron, burning it rapidly into iron oxide, and the kinetic energy of the stream blows the molten oxide out through the bottom of the cut (forming the kerf). It does not release acetylene or air.

Question 34Welding processes, joint preparation and controlled heat input

What is the term 'kerf' used to describe in oxy-fuel gas cutting?

  1. The width of the cut slot made by the high-pressure oxygen jet. Correct answer.
  2. The slag residue that clings to the bottom edge of the cut plate.
  3. The angle of inclination of the cutting torch head.
  4. The localized hardening of the steel near the cut face.

Explanation

In thermal cutting, the 'kerf' refers to the slot or gap width created by the removal of metal during the cutting process. The width of the kerf is determined by the size of the cutting nozzle (tip), the oxygen pressure, and the cutting speed. Welders must account for the kerf width when laying out and marking plates for fabrication to ensure final dimensions are accurate. Slag is called dross, and hardening is the heat-affected zone.

Question 35Welding processes, joint preparation and controlled heat input

What is the function of the multiple small flame orifices surrounding the central large oxygen orifice in an oxy-fuel cutting nozzle?

  1. To provide preheating flames that raise the steel to its ignition temperature. Correct answer.
  2. To mix the gases before they exit the torch head.
  3. To shield the cutting stream from the atmospheric nitrogen.
  4. To cool down the nozzle to prevent backfires.

Explanation

A cutting tip has a central hole for the high-pressure cutting oxygen stream, surrounded by a ring of smaller preheat orifices. These preheat orifices burn a mixture of oxygen and fuel gas to heat the steel surface to its ignition point (~900°C) before the high-pressure cutting oxygen is released. Without preheating, the cold steel would not react with the oxygen jet. Mixing occurs inside the torch body, not at the tip face.

Question 36Welding processes, joint preparation and controlled heat input

How is brazing differentiated from fusion welding, according to standard definitions?

  1. Brazing does not melt the base metal; it uses a filler metal that melts above 450°C and flows into the joint by capillary action. Correct answer.
  2. Brazing melts both the base metal and the filler metal at the same time.
  3. Brazing requires an electric arc power source to melt the copper alloy rod.
  4. Brazing is performed only on non-metallic materials like plastics.

Explanation

Brazing is a thermal joining process where the base metal is heated but never melted. Instead, a non-ferrous filler metal (like brass or bronze) with a melting point above 450°C (840°F) but below that of the base metal is introduced. The filler metal melts, wets the joint surfaces, and is drawn into the close-fitting joint by capillary action. Soldering is similar but uses filler metals that melt below 450°C, and fusion welding melts the base metal.

Question 37Welding processes, joint preparation and controlled heat input

Which type of joint is formed when two plates are placed in approximately the same plane with their edges abutting each other?

  1. Butt joint Correct answer.
  2. Lap joint
  3. Tee joint
  4. Corner joint

Explanation

A butt joint is a joint between two members aligned in approximately the same plane where the edges meet. Lap joints are formed by overlapping plates, tee joints are formed when one plate meets another at approximately 90 degrees in a 'T' shape, and corner joints meet at 90 degrees at their edges. Butt joints often require edge beveling to ensure full penetration.

Question 38Welding processes, joint preparation and controlled heat input

What is the technical term for a weld of approximately triangular cross-section joining two surfaces at right angles in a Tee joint?

  1. Fillet weld Correct answer.
  2. Groove weld
  3. Plug weld
  4. Slot weld

Explanation

A fillet weld is a weld of approximately triangular cross-section that joins two surfaces at right angles, such as in lap joints, tee joints, or corner joints. Groove welds are placed within a prepared groove or slot between members. Plug and slot welds are used to join overlapping members by filling pre-drilled holes or slots.

Question 39Welding processes, joint preparation and controlled heat input

What is the purpose of leaving a 'root opening' (root gap) at the bottom of a V-groove joint preparation before welding?

  1. To allow the weld metal to penetrate through the full thickness of the joint. Correct answer.
  2. To prevent the plates from expanding during heating.
  3. To reduce the amount of filler metal required to fill the joint.
  4. To make it easier to clean the slag after the weld is completed.

Explanation

The specified root opening provides access for the intended root-fusion process. Actual gap, root face, current, position and method work together under the approved procedure; a gap alone does not guarantee complete penetration or soundness. No universal dimension or authorization to change fit-up is provided.

Question 40Welding processes, joint preparation and controlled heat input

What is the 'root face' (land) in a groove weld joint preparation?

  1. The flat, narrow portion of the grooved edge that is perpendicular to the plate surface at the root. Correct answer.
  2. The top surface of the completed weld bead.
  3. The total angle formed between the two beveled edges.
  4. The backing plate placed under the joint.

Explanation

The root face, often called the 'land', is the narrow, flat portion of the joint edge that is left unbeveled at the root of the joint. Its function is to support the heat of the arc and prevent burn-through, especially on thin or medium plates. A land thickness of 1.5 mm to 2.5 mm is standard. The top surface of the weld is the weld face, the beveled angle is the groove angle, and the backing plate is backing.

Question 41Welding processes, joint preparation and controlled heat input

In the standard AWS welding positions for plates, what does the designation '3G' represent?

  1. Vertical groove welding Correct answer.
  2. Horizontal fillet welding
  3. Overhead groove welding
  4. Flat position fillet welding

Explanation

In AWS plate classifications, the number designates the position: '1' for flat, '2' for horizontal, '3' for vertical, and '4' for overhead. The letter 'G' indicates a groove weld, and 'F' indicates a fillet weld. Therefore, '3G' represents vertical groove welding. This position is demanding as gravity pulls the molten weld pool down, requiring precise electrode manipulation.

Question 42Welding processes, joint preparation and controlled heat input

What does the plate welding designation '4G' represent, and how does gravity affect this weld pool?

  1. Overhead groove welding; gravity tends to pull the molten metal out of the joint, requiring a very short arc length. Correct answer.
  2. Vertical fillet welding; gravity causes the slag to run ahead of the weld pool.
  3. Horizontal groove welding; gravity pulls the weld metal to the bottom plate.
  4. Flat groove welding; gravity helps to flatten the weld profile.

Explanation

The '4G' position is overhead groove welding. In this position, the weld is executed from the underside of the joint. Gravity acts directly against the weld pool, pulling the molten metal down. To counteract this, the welder must maintain a very short arc length and travel at a speed that prevents the puddle from overheating and dripping. Vertical fillet is 3F, horizontal groove is 2G, and flat groove is 1G.

Question 43Welding processes, joint preparation and controlled heat input

Which pipe welding position is designated as '5G'?

  1. The pipe axis is horizontal and fixed; the weld is run vertically (upward or downward) around the circumference. Correct answer.
  2. The pipe axis is vertical and fixed; the weld is run horizontally around the circumference.
  3. The pipe is rotated while the torch remains stationary at the top.
  4. The pipe is fixed at a 45-degree angle.

Explanation

In pipe welding, '5G' refers to a fixed horizontal pipe (axis is horizontal). The welder must weld around the circumference of the fixed pipe, which forces them to transition through multiple positions: flat (top), vertical (sides), and overhead (bottom). It is a major test of a welder's skill. 2G is a fixed vertical pipe (horizontal weld), and 6G is fixed at 45 degrees.

Question 44Welding processes, joint preparation and controlled heat input

What position is represented by the designation '2F' for plate welding?

  1. Horizontal fillet weld Correct answer.
  2. Flat groove weld
  3. Vertical groove weld
  4. Overhead fillet weld

Explanation

The designation '2F' represents a horizontal fillet weld. In this position, the weld is executed along a horizontal line on a vertical or near-vertical plate surface. The molten metal tends to sag toward the bottom plate due to gravity, which the welder must counteract by angling the electrode slightly upward (approximately 45 to 50 degrees to the horizontal plate). 1G is flat groove, 3G is vertical groove, and 4F is overhead fillet.

Question 45Welding processes, joint preparation and controlled heat input

What is the purpose of using a backing strip (backing bar) in a single-V groove butt joint?

  1. To support the molten root pass and prevent burn-through in joints with wide gaps. Correct answer.
  2. To prevent the plates from warping under high temperatures.
  3. To increase the speed of slag solidification.
  4. To protect the welder from ground currents.

Explanation

The specified backing supports the molten root region within its designed procedure. Actual backing compatibility, removal requirements, root condition and inspection matter. It does not independently guarantee complete penetration, eliminate burn-through in every case or authorize a generic change to the joint design.

Question 46Welding processes, joint preparation and controlled heat input

What is the primary purpose of a 'tack weld' during the assembly of a welded joint?

  1. To hold the joint members in proper alignment and maintain the correct root opening before final welding. Correct answer.
  2. To test the welding current settings on the scrap portion of the plate.
  3. To act as a moisture barrier to protect the joint root.
  4. To increase the strength of the final weld bead.

Explanation

Tack welds are small, temporary welds placed at intervals along a joint. Their purpose is to hold the plates or pipes in proper alignment and maintain the root gap during assembly and final welding operations. If tacking is poor, the heat of the main weld will pull the plates together, closing the root gap and causing defects. Tacks do not test current, act as moisture barriers, or increase strength.

Question 47Welding processes, joint preparation and controlled heat input

What is the difference between the 'bevel angle' and the 'groove angle' in a V-groove butt joint?

  1. The bevel angle is the angle of preparation on a single plate; the groove angle is the total included angle between both prepared plates. Correct answer.
  2. The bevel angle is always 90 degrees, whereas the groove angle is always 45 degrees.
  3. The bevel angle is measured with a micrometer, while the groove angle is measured with a ruler.
  4. There is no difference; both terms describe the exact same angle.

Explanation

The bevel angle is the angle cut on the edge of a single plate (typically 30 to 37.5 degrees). The groove angle (or included angle) is the total angle formed between the two beveled plates when they are fitted up (typically 60 to 75 degrees). The groove angle is the sum of both bevel angles. They are not measured with micrometers or rulers, but with specialized welding gauges.

Question 48Weld imperfections, inspection evidence and repair control

What is 'underfill' in welding, and how is it distinguished from 'undercut'?

  1. Underfill is when the weld face is below the adjacent surface of the base metal; undercut is a groove melted into the base metal at the weld toe. Correct answer.
  2. Underfill occurs only at the root pass; undercut occurs only at the cap pass.
  3. Underfill is caused by a low travel speed; undercut is caused by a high travel speed.
  4. Underfill is a destructive testing method; undercut is a non-destructive testing method.

Explanation

Underfill is a weld profile defect where the weld metal deposit is insufficient, leaving the weld face or root surface below the adjacent surface of the base metal (the joint is not completely filled). Undercut is a sharp groove melted into the base metal along the toe of the weld. Underfill is corrected by adding more weld passes, while undercut may require grinding and low-heat touch-up passes.

Question 49Weld imperfections, inspection evidence and repair control

What is the primary limitation of Liquid Penetrant Testing (LPT/PT) when inspecting weldments?

  1. It can only detect discontinuities that are open to the surface of the weld. Correct answer.
  2. It can only be used on magnetic (ferromagnetic) metals.
  3. It requires expensive high-voltage X-ray equipment to read the results.
  4. It permanently stains the weld, making it unusable in structural applications.

Explanation

Liquid Penetrant Testing (LPT) relies on capillary action to draw a liquid dye into surface-breaking discontinuities. Therefore, its primary limitation is that it can only detect defects that are open to the surface (like surface cracks, pinholes, and seams). It cannot detect internal, sub-surface defects (like internal slag inclusions or lack of fusion). It is highly versatile and works on non-magnetic metals.

Question 50Weld imperfections, inspection evidence and repair control

Which of the following materials is Magnetic Particle Testing (MPT/MT) suitable for inspecting?

  1. Carbon steels and low-alloy steels (ferromagnetic materials) Correct answer.
  2. Aluminum alloys and copper sheets
  3. Austenitic stainless steel plates
  4. Plastics and composite carbon fibers

Explanation

Magnetic Particle Testing (MPT) requires magnetizing the specimen. Therefore, it is only suitable for ferromagnetic materials (such as carbon steels, cast irons, and low-alloy steels) which can hold a magnetic flux. Non-magnetic metals like aluminum, copper, and austenitic stainless steels cannot be inspected using MPT. Plastics are completely non-magnetic and cannot be tested.