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Red Seal Welder practice questions

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Question 1Occupational Skills and Safety

Under CSA W117.2, which practice is required before a welder begins work in a confined space such as a tank interior?

  1. A documented atmospheric test and a standby attendant at the entry point Correct answer.
  2. Opening the manway and starting work immediately to save time
  3. A verbal agreement among the crew that the air smells acceptable
  4. Relying on the welder's own sense of smell to detect gas

Explanation

Confined-space entry under CSA W117.2 and provincial OHS rules requires testing the atmosphere for oxygen, flammables, and toxics before entry, plus continuous ventilation and a standby attendant outside. The welding arc also consumes oxygen and generates fumes, so monitoring continues during the work.

Question 2Occupational Skills and Safety

Which type of fire extinguisher is appropriate for a small fire involving the acetylene hose and fittings at an oxy-fuel station?

  1. Class A water extinguisher
  2. Class D sodium chloride extinguisher
  3. Class C carbon dioxide extinguisher
  4. Class B dry chemical extinguisher Correct answer.

Explanation

Compressed gases such as acetylene are classified as Class B flammable gas/liquid hazards, so a dry chemical extinguisher rated for Class B is appropriate. Water is dangerous on gas fires because it can spread burning material and does not smother the flame. Class D agents are formulated for combustible metals, and Class C ratings apply to energized electrical equipment.

Question 3Occupational Skills and Safety

A welder is preparing to strike an arc on a workpiece held in a positioner. Which personal protective equipment is essential to protect against arc radiation and spatter?

  1. Safety glasses alone
  2. A welding helmet with appropriate shade lens, leather gloves, and flame-resistant sleeves Correct answer.
  3. A dust mask and cotton coveralls
  4. A hard hat and steel-toed boots only

Explanation

Arc welding emits intense ultraviolet and infrared radiation that can damage the eyes and skin, so a helmet with a properly shaded filter lens, leather gloves, and flame-resistant sleeves are required. Safety glasses alone do not block arc radiation, and cotton coveralls do not resist spatter ignition.

Question 4Occupational Skills and Safety

Before using a portable oxy-acetylene torch, a welder should perform which check on the hoses?

  1. Increase acetylene pressure beyond the working range to test the regulator
  2. Tape over any worn spots to extend hose life
  3. Immerse the entire hose in water to check for bubbles
  4. Leak-test all connections with soapy water and inspect hoses for cracks or burns Correct answer.

Explanation

Hose and connection leaks are detected by applying soapy water and watching for bubbles, along with a visual inspection for cracks, burns, or worn areas. Acetylene must never exceed 15 psi (103 kPa) in the hose and taping worn hoses is prohibited because it hides defects and is not a pressure-tight repair.

Question 5Occupational Skills and Safety

What is the primary purpose of a hot work permit when welding in a plant or shop?

  1. To authorize overtime work on weekends
  2. To document that fire hazards were assessed and controls put in place before ignition sources are introduced Correct answer.
  3. To record the welder's certification number for payroll
  4. To confirm the welder has read the shop's vacation schedule

Explanation

A hot work permit is a formal control that confirms combustible materials are removed or protected, fire watch arrangements are made, and the area is safe before any spark- or flame-producing activity begins. It is a fire-prevention document, not an administrative or payroll record.

Question 6Occupational Skills and Safety

Which statement correctly describes the safe handling of a compressed gas cylinder in a welding shop?

  1. Cylinders may be laid horizontally if chained to a bench
  2. Cylinders should be stored with regulators attached and valves open
  3. Cylinders should be secured upright and kept away from heat sources and electrical circuits Correct answer.
  4. Cylinders may be used as rollers to move heavy plate

Explanation

Compressed gas cylinders must be stored and used upright, secured against tipping, and kept away from heat, sparks, and electrical circuits that could arc onto them. Regulators should be removed and valve protection caps replaced for storage and transport.

Question 7Occupational Skills and Safety

Which welding process uses a constant-current power source with a drooping volt-ampere characteristic?

  1. Shielded metal arc welding (SMAW) Correct answer.
  2. Flux-cored arc welding (FCAW)
  3. Submerged arc welding (SAW)
  4. Gas metal arc welding (GMAW)

Explanation

SMAW relies on a constant-current (drooping) characteristic so that arc-length changes cause little current change, which stabilizes the manual arc. Wire-feed processes such as GMAW, FCAW, and SAW use constant-voltage or variable-characteristic sources to self-regulate wire burn-off.

Question 8Occupational Skills and Safety

A welder is welding 6 mm mild steel plate in the flat position with a 3.2 mm E7018 electrode. Which current setting is most appropriate?

  1. Approximately 120 A DCEP Correct answer.
  2. Approximately 300 A DCEN
  3. Approximately 600 A AC
  4. Approximately 40 A DCEP

Explanation

A 3.2 mm (1/8 in) E7018 electrode is typically run at about 110 to 140 A on direct current electrode positive, which suits 6 mm plate in the flat position. Settings far outside this range cause poor fusion, excessive spatter, or burn-through.

Question 9Occupational Skills and Safety

A welder notices the arc in GMAW is unstable, with excessive spatter and a stubbing sound. Which parameter adjustment is most likely needed?

  1. Decrease shielding gas flow to zero
  2. Increase wire-feed speed significantly
  3. Increase voltage slightly to lengthen the arc Correct answer.
  4. Decrease voltage to shorten the arc

Explanation

A stubbing, spattery arc in GMAW usually indicates the voltage is too low relative to wire-feed speed, so the wire stubs into the puddle. Raising voltage slightly lengthens the arc and stabilizes transfer. Cutting gas flow to zero would destroy shielding and is never appropriate.

Question 10Occupational Skills and Safety

A welder must weld a thin 1.5 mm sheet without burn-through. Which technique best reduces heat input?

  1. Use a smaller electrode, lower current, and faster travel speed Correct answer.
  2. Preheat the sheet to 200 °C before welding
  3. Increase current and travel speed together
  4. Use a larger electrode and higher current

Explanation

Heat input is proportional to current and voltage and inversely related to travel speed, so a smaller electrode, reduced current, and faster travel speed all lower heat input. Preheating increases heat input and would promote burn-through on thin sheet.

Question 11Occupational Skills and Safety

What is the main reason for preheating thick, high-carbon steel before welding?

  1. To reduce the risk of hydrogen-assisted cold cracking by slowing the cooling rate Correct answer.
  2. To increase the arc voltage automatically
  3. To eliminate the need for any post-weld inspection
  4. To increase the electrode deposition rate

Explanation

Preheating slows the cooling rate after welding, which reduces the formation of hard martensite and lowers the risk of hydrogen-assisted cold cracking in thick or high-carbon steel. It does not change arc voltage or remove the need for inspection.

Question 12Occupational Skills and Safety

A welder is welding aluminum with GMAW and observes a black, sooty deposit and poor fusion. Which change is most appropriate?

  1. Use DCEP with argon shielding gas and clean the oxide layer before welding Correct answer.
  2. Add carbon dioxide to the shielding gas mixture
  3. Switch to DCEN and reduce gas flow
  4. Increase travel speed and reduce voltage

Explanation

Aluminum forms a tenacious oxide that must be removed mechanically before welding, and GMAW of aluminum normally uses DCEP with argon or argon-helium shielding to break up the oxide during the arc. Adding CO2 or reducing gas flow causes soot and poor fusion.

Question 13Occupational Skills and Safety

A welder must join two pieces of 12 mm steel plate with full penetration. Which joint preparation is typically required?

  1. Single-V groove with a root opening and backing or back gouging Correct answer.
  2. Corner joint with a single pass
  3. Square butt with no root opening
  4. Lap joint with a single fillet weld

Explanation

Full penetration in 12 mm plate generally requires a groove preparation such as a single-V with a root opening, plus backing or back gouging to ensure complete fusion through the thickness. A square butt without an opening cannot achieve full penetration at that thickness.

Question 14Occupational Skills and Safety

Which distortion control method involves alternating the welding sequence from one side of the joint to the other?

  1. Back-step welding
  2. Preheating
  3. Balanced (alternating) welding Correct answer.
  4. Peening

Explanation

Balanced or alternating welding distributes heat evenly on both sides of a joint to balance shrinkage forces and limit angular distortion. Back-step welding controls distortion along the length of a joint but does not alternate sides.

Question 15Occupational Skills and Safety

A welder is using a semi-automatic FCAW process with self-shielded wire outdoors. Which precaution is most important on a windy day?

  1. Reduce the current to the minimum setting
  2. Weld in a downhand position only
  3. Use a windbreak or switch to a self-shielded wire designed for outdoor use Correct answer.
  4. Increase the wire-feed speed to compensate for wind

Explanation

Wind can blow away shielding gas in gas-shielded FCAW, causing porosity, so a windbreak is needed or a self-shielded wire designed for outdoor use should be selected. Increasing wire-feed speed or lowering current does not replace lost shielding.

Question 16Occupational Skills and Safety

What is the purpose of back gouging in a double-groove weld?

  1. To remove unsound metal at the root until sound metal is reached before welding the second side Correct answer.
  2. To remove slag from the weld cap
  3. To increase the travel speed of the second pass
  4. To reduce the preheat requirement

Explanation

Back gouging removes the unsound root material from the first side until sound metal is exposed, allowing the second side to be welded with full penetration. It is a soundness requirement, not a slag-removal or speed step.

Question 17Occupational Skills and Safety

A welder is asked to weld a pressure vessel joint that requires procedure qualification. Which document defines the welding variables that must be followed?

  1. The welder's pay stub
  2. The shop's material safety data sheet
  3. The equipment maintenance log
  4. The welding procedure specification (WPS) Correct answer.

Explanation

The WPS lists the qualified variables such as process, filler, current range, preheat, and technique that the welder must follow. Procedure qualification records support the WPS, but the WPS is the working document the welder uses at the joint.

Question 18Occupational Skills and Safety

A welder is using a plasma arc cutting torch on stainless steel. Which hazard is of particular concern compared with cutting mild steel?

  1. Hexavalent chromium fume generation requiring enhanced ventilation and respiratory protection Correct answer.
  2. Reduced arc temperature requiring higher current
  3. Increased risk of hydrogen embrittlement in the cut edge
  4. Loss of electrical conductivity

Explanation

Cutting stainless steel generates fumes containing hexavalent chromium and nickel, which are carcinogenic and require enhanced ventilation and appropriate respiratory protection. Plasma cutting does not reduce arc temperature or rely on the workpiece's conductivity in the same way.

Question 19Occupational Skills and Safety

A welder is welding in the vertical-up position with SMAW. Which technique helps control the puddle and produce good fusion?

  1. Using a short arc with a slight weave and pausing at the edges Correct answer.
  2. Increasing current to maximum and dragging the electrode
  3. Using a long arc and fast travel
  4. Welding downhill with a whip motion

Explanation

Vertical-up welding requires a short arc, a controlled weave, and brief pauses at the sidewalls to allow fusion and to let the puddle solidify before moving on. A long arc or excessive current causes the puddle to sag and lose fusion.

Question 20Occupational Skills and Safety

A welder is asked to weld a joint in a galvanized steel structure. Which control is most important to address the fume hazard?

  1. Use a CO2 extinguisher nearby
  2. Weld without a helmet to improve visibility
  3. Weld at full current to finish quickly
  4. Remove the zinc coating in the weld zone and use local exhaust ventilation Correct answer.

Explanation

Welding galvanized steel produces zinc oxide fume that can cause metal fume fever, so the coating should be removed from the weld zone where practical and local exhaust ventilation used. Increasing current increases fume generation, and removing the helmet is never acceptable.

Question 21Occupational Skills and Safety

A welder is troubleshooting porosity in a GMAW weld on mild steel. Which set of causes should be investigated first?

  1. Excessive travel speed and too little current
  2. Too much preheat and too slow a cooling rate
  3. Contaminated base metal, moisture on the wire, or inadequate shielding gas flow Correct answer.
  4. Electrode too dry and too much backing

Explanation

Porosity in GMAW commonly results from contamination such as oil, rust, or moisture, or from inadequate or disrupted shielding gas flow. Travel speed and current affect bead shape and fusion more than they cause gas porosity directly.

Question 22Occupational Skills and Safety

A welder needs to make a square butt weld in 3 mm sheet using GTAW on aluminum. Which setup is correct?

  1. AC current with oxygen shielding and a copper electrode
  2. AC current with argon shielding and a tungsten electrode Correct answer.
  3. DCEN with CO2 shielding and a mild steel filler
  4. DCEP with no shielding gas and a carbon electrode

Explanation

GTAW on aluminum uses alternating current so the electrode-positive half-cycle cleans the oxide while the electrode-negative half-cycle limits tungsten erosion, with argon shielding and a tungsten electrode. CO2, oxygen, and carbon electrodes are not appropriate for aluminum GTAW.

Question 23Occupational Skills and Safety

A welder is welding a thick section of low-alloy steel and the procedure specifies a maximum interpass temperature. Why is this limit important?

  1. To avoid excessive grain growth and loss of toughness in the heat-affected zone Correct answer.
  2. To increase the deposition rate of the electrode
  3. To ensure the weld cools slowly enough to prevent cracking
  4. To reduce the need for post-weld heat treatment

Explanation

Excessive interpass temperature can cause grain growth and reduced toughness in the heat-affected zone, so procedures set an upper limit. A maximum interpass limit does not slow cooling; it prevents the workpiece from becoming too hot between passes.

Question 24Occupational Skills and Safety

A welder is welding a circumferential pipe joint in the 6G position. Which challenge is unique to this position?

  1. The root pass is always made with a backing strip
  2. The pipe can be rotated to keep the weld flat
  3. The weld is always made in the flat position
  4. The weld must be made in all positions around the pipe with a fixed workpiece Correct answer.

Explanation

The 6G position fixes the pipe at a 45-degree incline so the welder must weld overhead, vertical, and flat around the circumference without rotating the pipe. This tests the welder's ability to control the puddle in all positions.

Question 25Tools and Equipment

When setting up oxy-acetylene equipment for cutting, which regulator is fitted to the oxygen cylinder?

  1. An oxygen regulator with a right-hand thread connection Correct answer.
  2. A single universal regulator suitable for either gas
  3. A fuel-gas regulator with a left-hand thread connection
  4. An inert-gas regulator with a CGA 580 fitting

Explanation

Oxygen regulators use right-hand threads and are marked for oxygen service only, while fuel-gas fittings use left-hand threads. Regulators are gas-specific and must never be interchanged, because residual oil or incompatible materials in the wrong regulator can ignite.

Question 26Tools and Equipment

What is the primary purpose of the flashback arrestor installed on an oxy-fuel torch or hose?

  1. To filter particulate contamination from the gas stream
  2. To prevent the mixer from overheating during long cuts
  3. To reduce cylinder pressure to a steady working pressure
  4. To stop a flame from travelling back into the hose and regulator Correct answer.

Explanation

A flashback arrestor contains a quenching element and check valve that stop a flame front or reverse gas flow from reaching the hose, regulator, and cylinder. This protects the operator and equipment from a potentially explosive event.

Question 27Tools and Equipment

Which PPE is specifically required when operating an arc welding process that emits high ultraviolet radiation?

  1. Clear safety glasses alone with a cotton shop apron
  2. A welding helmet with the appropriate shade lens and a flame-resistant jacket Correct answer.
  3. Tinted sunglasses with a respirator and rubber boots
  4. A face shield rated for grinding with leather work gloves

Explanation

Arc welding emits intense UV and IR radiation, so a helmet with the correct filter shade protects the eyes and face, and flame-resistant clothing protects skin from spatter and radiation burns. Clear glasses alone do not block the arc's UV.

Question 28Tools and Equipment

Before using a portable angle grinder, what is the correct practice regarding the guard?

  1. Replace the guard with a wire wheel for faster cleaning
  2. Loosen the guard so it can rotate freely during use
  3. Leave the guard in place and position it to deflect sparks and debris Correct answer.
  4. Remove the guard to allow access into tight corners

Explanation

The wheel guard must remain fitted and adjusted so the open side directs sparks away from the operator and shields the unexposed portion of the wheel. Removing or loosening it exposes the operator to burst-wheel fragments and debris.

Question 29Tools and Equipment

Which electrode holder characteristic is most important for safe manual shielded metal arc welding?

  1. A holder sized for the largest electrode available
  2. Fully insulated jaws that grip the electrode securely Correct answer.
  3. Lightweight aluminium jaws that conduct little current
  4. An uninsulated holder for better heat dissipation

Explanation

An electrode holder must be fully insulated to protect the welder from the open-circuit voltage and must grip the electrode firmly to maintain a stable arc. A holder that is not insulated or does not grip securely creates shock and arc-instability hazards.

Question 30Tools and Equipment

A welder is preparing to cut 25 mm thick mild steel with an oxy-acetylene torch. Which adjustment best supports a clean, complete cut?

  1. Use a small cutting tip with low oxygen pressure and a slow travel speed
  2. Select a larger cutting tip, set the correct preheat flame, and maintain steady travel speed Correct answer.
  3. Use a neutral flame with maximum acetylene pressure and no oxygen jet
  4. Set a carburizing flame and cut with the tip held well above the plate

Explanation

Thick plate requires a larger orifice tip to supply enough oxygen for the kerf and adequate preheat to start the cut. Matching tip size, flame setting, and travel speed produces a clean kerf instead of dross and incomplete penetration.

Question 31Tools and Equipment

During GMAW, the wire feed motor runs but the wire slips and stutters at the drive rolls. What is the most likely cause?

  1. The work lead is connected to the wrong terminal
  2. The drive roll tension is too low or the contact tip is clogged Correct answer.
  3. The gun liner is too short for the cable length
  4. The shielding gas flow is set too high

Explanation

Wire slip and stutter usually indicate insufficient drive-roll tension, a worn or wrong-groove drive roll, or excessive drag from a clogged contact tip or kinked liner. Adjusting tension and checking the contact tip and liner restores smooth feed.

Question 32Tools and Equipment

A welder needs to remove rust, mill scale, and old paint from a structural joint before welding. Which power tool is the most appropriate choice?

  1. A hole saw with a carbide arbor
  2. A reciprocating saw with a metal-cutting blade
  3. A hard-wheel chop saw with an abrasive disc
  4. A stringer bead wire brush on an angle grinder Correct answer.

Explanation

A wire brush or grinding wheel on an angle grinder is designed to clean surfaces of scale, rust, and paint to prepare for welding. Cutting tools such as chop saws and reciprocating saws remove material along a kerf rather than cleaning a surface.

Question 33Tools and Equipment

A welding machine is rated at 60 percent duty cycle at 200 A. What does this rating mean for the operator?

  1. The machine can weld continuously at 200 A without any rest period
  2. The machine can weld 6 minutes out of every 10 at 200 A before cooling is needed Correct answer.
  3. The machine delivers 60 percent of its maximum current at all times
  4. The machine must be shut down for 6 minutes after every 1 minute of welding

Explanation

Duty cycle is the percentage of a 10-minute period a machine can operate at a stated current without exceeding its thermal limit. At 60 percent, it can run 6 minutes at 200 A and must cool for the remaining 4 minutes.

Question 34Tools and Equipment

What is the main reason for using a shielding gas mixture of argon and carbon dioxide in GMAW of carbon steel?

  1. To improve arc stability and weld bead shape compared with pure CO2 Correct answer.
  2. To eliminate the need for a contact tip
  3. To allow welding without any wire feed mechanism
  4. To increase the deposition rate by raising the melting point of the wire

Explanation

Argon-rich mixtures with CO2 provide a stable spray or short-circuit arc, better bead appearance, and reduced spatter than pure CO2 in many carbon steel applications. The mixture balances arc stability with the oxidizing and penetrating effect of CO2.

Question 35Tools and Equipment

A welder is setting up a plasma cutting unit on a CNC table. Which parameter most directly controls cut quality and dross formation on thin sheet?

  1. The cutting current, travel speed, and torch standoff height Correct answer.
  2. The diameter of the work lead cable jacket
  3. The angle of the ground clamp handle
  4. The color of the torch shield cup

Explanation

Plasma cut quality depends on matching cutting current, travel speed, and standoff to the material thickness; too much current or too slow a speed produces dross and a wide kerf. These parameters are adjusted together for a clean cut edge.

Question 36Tools and Equipment

A welder is using a portable band saw to cut structural steel sections to length. Which practice best extends blade life and improves cut accuracy?

  1. Cut without coolant and allow the blade to overheat
  2. Start the cut at the blade's leading edge with the work unclamped
  3. Run the blade at maximum speed with heavy feed pressure
  4. Use the correct blade pitch, apply steady moderate feed, and support the work securely Correct answer.

Explanation

Matching blade pitch to section thickness, maintaining moderate feed, and clamping the work securely reduce tooth breakage and heat buildup. Excessive speed or feed overheats the blade and shortens its life.

Question 37Tools and Equipment

An operator notices the electrode holder cable on a SMAW machine is cracked and shows exposed copper. What is the correct action?

  1. Hold the cable away from the work with a gloved hand while welding
  2. Reduce the welding current and continue using the cable
  3. Wrap the damaged section with electrical tape and continue welding
  4. Remove the cable from service and repair or replace it before welding Correct answer.

Explanation

Cracked insulation with exposed conductors presents a serious shock and arc-flash hazard, so the cable must be taken out of service and repaired or replaced. Taping or working around the damage does not restore the required insulation integrity.

Question 38Tools and Equipment

A welder must select a tungsten electrode for DCEN TIG welding of thin stainless steel. Which choice is generally preferred?

  1. A carbon gouging electrode with a copper coating
  2. Thoriated or ceriated tungsten with a pointed tip Correct answer.
  3. Pure tungsten with a balled tip
  4. Aluminium filler wire used as the electrode

Explanation

For DCEN TIG welding, a pointed tungsten with an alloying oxide such as thoria or ceria provides a stable arc and good current-carrying capacity. Pure tungsten is generally used for AC welding of aluminium, where a balled tip is typical.

Question 39Tools and Equipment

A welder is troubleshooting porosity in a GMAW weld on clean carbon steel. Which equipment-related cause should be checked first?

  1. Insufficient shielding gas flow or a leak in the gas delivery system Correct answer.
  2. A cutting tip that is too large for the plate
  3. Excessive drive roll pressure on the wire
  4. A tungsten electrode that is too short

Explanation

Porosity in GMAW is commonly caused by inadequate or contaminated shielding gas, such as low flow, leaks, drafts, or a clogged nozzle. Checking the gas delivery system first addresses the most frequent equipment-related cause.

Question 40Tools and Equipment

A welder is setting up an oxy-fuel cutting torch and observes the flame has a bright inner cone with a slightly feathered outer envelope after adjusting the oxygen. What does this indicate and what should be done?

  1. An oxidizing flame; increase acetylene until the inner cone is sharp Correct answer.
  2. A flashback; shut off the oxygen and relight the torch
  3. A carburizing flame; decrease oxygen until the flame is neutral
  4. A neutral flame; proceed with cutting without further adjustment

Explanation

A feathered outer envelope indicates excess acetylene, while a shortened, hissing inner cone with a pale outer flame indicates excess oxygen. A proper neutral flame has a clearly defined inner cone and a smooth outer envelope, so the fuel or oxygen must be balanced accordingly.

Question 41Applied Trade Mathematics

A fillet weld has a leg length of 6 mm. Using the standard 45° mitre relationship, what is the theoretical throat thickness?

  1. 6.0 mm
  2. 3.0 mm
  3. 4.2 mm Correct answer.
  4. 8.5 mm

Explanation

For a 45° fillet weld the throat equals the leg multiplied by sin 45°, which is 0.707. Multiplying 6 mm by 0.707 gives approximately 4.24 mm, conventionally rounded to 4.2 mm.

Question 42Applied Trade Mathematics

A weld is specified with a 3/8 in leg fillet. What is this dimension in millimetres, to one decimal place?

  1. 6.4 mm
  2. 7.9 mm
  3. 12.7 mm
  4. 9.5 mm Correct answer.

Explanation

One inch equals 25.4 mm, so 3/8 in equals 0.375 × 25.4 = 9.525 mm, which rounds to 9.5 mm. Converting the fraction to a decimal first avoids errors when scaling.

Question 43Applied Trade Mathematics

A rectangular steel plate measures 1.2 m by 0.8 m. What is its area in square metres?

  1. 0.48 m²
  2. 0.96 m² Correct answer.
  3. 2.00 m²
  4. 1.60 m²

Explanation

Area of a rectangle is length times width, so 1.2 m × 0.8 m = 0.96 m². Keeping both dimensions in the same unit before multiplying prevents conversion mistakes.

Question 44Applied Trade Mathematics

A weld symbol shows a groove weld with a root gap of 2 mm and a root face of 1.5 mm on a 10 mm plate. What total joint preparation depth is consumed by gap plus root face?

  1. 3.5 mm Correct answer.
  2. 5.0 mm
  3. 1.5 mm
  4. 2.0 mm

Explanation

The root gap and root face stack together in the joint preparation, so 2 mm + 1.5 mm = 3.5 mm. These are added, not multiplied, because they are separate linear features of the same joint.

Question 45Applied Trade Mathematics

A welding procedure lists a travel speed of 250 mm/min. How long will it take to run a continuous 1.5 m weld?

  1. 6 minutes Correct answer.
  2. 15 minutes
  3. 3.75 minutes
  4. 0.6 minutes

Explanation

Convert 1.5 m to 1500 mm, then divide by 250 mm/min to get 6 minutes. Matching units before dividing is essential when travel speed is given in millimetres.

Question 46Applied Trade Mathematics

A cylindrical pressure vessel has an outside diameter of 508 mm and a wall thickness of 12.7 mm. What is the inside diameter?

  1. 508.0 mm
  2. 495.3 mm
  3. 520.7 mm
  4. 482.6 mm Correct answer.

Explanation

Inside diameter equals outside diameter minus twice the wall thickness, because the wall exists on both sides. Thus 508 − (2 × 12.7) = 508 − 25.4 = 482.6 mm.

Question 47Applied Trade Mathematics

A weld deposit has a cross-sectional area of 30 mm² and the joint is 400 mm long. What is the deposited weld volume?

  1. 4 300 mm³
  2. 1 200 mm³
  3. 13 333 mm³
  4. 12 000 mm³ Correct answer.

Explanation

Volume of a uniform weld run equals cross-sectional area times length, so 30 mm² × 400 mm = 12 000 mm³. This value is used with deposit efficiency to estimate filler consumption.

Question 48Applied Trade Mathematics

A fillet weld has a 10 mm leg and is 3 m long. Using a throat thickness of 7.07 mm, what is the approximate weld cross-sectional area?

  1. 50.0 mm²
  2. 35.4 mm²
  3. 100.0 mm²
  4. 70.7 mm² Correct answer.

Explanation

The cross-section of a mitre fillet is half the product of leg and throat, so 0.5 × 10 × 7.07 = 35.35 mm². However, when the area is computed as leg × throat for a right-triangle fillet the standard formula gives 10 × 7.07 ≈ 70.7 mm² of theoretical triangle; the conventional half-triangle value is 35.4 mm².

Question 49Applied Trade Mathematics

A welding machine draws 28 A at 24 V with an efficiency of 0.85. What is the input power required from the supply, to the nearest 0.1 kW?

  1. 0.95 kW
  2. 0.57 kW
  3. 0.67 kW
  4. 0.79 kW Correct answer.

Explanation

Output power is 28 A × 24 V = 672 W. Dividing by efficiency 0.85 gives 790.6 W, or about 0.79 kW drawn from the supply.

Question 50Applied Trade Mathematics

A drawing specifies a 60° included-angle V-groove. What is the bevel angle on each plate?

  1. 45°
  2. 20°
  3. 30° Correct answer.
  4. 60°

Explanation

A V-groove is formed by two bevels, so the included angle is split equally between the plates. Half of 60° is 30° per plate.