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GTAW NC II study materials
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GTAW NC II practice questions

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Question 1Workplace safety, health, and environment (OHS) compliance

In GTAW, why is it standard practice to weld with the torch held at a relatively steep, near-vertical angle while keeping the arc short?

  1. A short arc prevents the tungsten electrode from ever touching the workpiece during filler addition
  2. A short arc increases deposition rate by transferring filler metal through the arc rather than the pool
  3. A steep torch angle allows the welder to use higher current without exceeding the electrode's amperage rating
  4. A short arc concentrates shielding gas coverage and heat, reducing atmospheric contamination of the molten pool Correct answer.

Explanation

The gas tungsten arc welding process relies on the inert shield to protect both the tungsten and the molten pool; a short arc keeps the gas envelope tight and limits the distance air can travel inward. A steep torch angle also directs heat into the joint rather than spreading it. Neither practice changes the electrode's amperage rating or guarantees the tungsten never contacts the work.

Question 2Workplace safety, health, and environment (OHS) compliance

A welder must perform GTAW inside a confined vessel. Which combination of controls is required before entry is permitted?

  1. Atmospheric testing, forced ventilation, an attendant at the entry, and a documented entry permit Correct answer.
  2. Only a supplied-air respirator, since welding fume is the sole hazard inside a tank
  3. Verbal confirmation from the welder that the space feels safe to enter
  4. A face shield and leather gloves, because PPE alone controls confined-space hazards

Explanation

Confined-space entry requires atmospheric testing for oxygen and contaminants, ventilation, a trained attendant stationed outside, and an authorized permit before anyone enters. Argon and helium shielding gases displace oxygen, so asphyxiation risk is significant even when the space looks clear. PPE and self-assessment cannot substitute for these engineered and administrative controls.

Question 3Workplace safety, health, and environment (OHS) compliance

GTAW uses argon and helium shielding gases stored in high-pressure cylinders. Which handling practice is correct?

  1. Secure cylinders upright with a chain or strap and keep the valve cap on until the regulator is fitted Correct answer.
  2. Remove the valve protection cap before moving the cylinder so the regulator can be inspected
  3. Lay cylinders horizontally on the floor so they cannot tip over during welding
  4. Store oxygen and argon cylinders together in a closed cabinet to keep them dry

Explanation

Compressed gas cylinders must be kept upright and restrained so a fall cannot shear the valve and turn the cylinder into a projectile. The valve protection cap stays on during transport and storage and is removed only when the regulator is installed. Oxygen must be separated from fuel gases, and no cylinder should be laid down in service.

Question 4Workplace safety, health, and environment (OHS) compliance

Why is it dangerous to weld GTAW on a workpiece that has just been cleaned with a chlorinated solvent?

  1. Chlorinated solvents attract moisture, which causes porosity in the weld bead
  2. Heat and ultraviolet radiation decompose the solvent into phosgene and other toxic gases Correct answer.
  3. The solvent residue increases arc voltage and can damage the high-frequency start unit
  4. The solvent reacts with argon to form a flammable mixture inside the gas line

Explanation

Chlorinated degreasers such as trichloroethylene break down under welding heat and UV radiation into phosgene and hydrogen chloride, which are acutely toxic. The workpiece must be fully dry and the solvent removed before any arc is struck. Porosity and arc-start problems are not the reason this practice is prohibited.

Question 5Workplace safety, health, and environment (OHS) compliance

Which PPE is specifically required for GTAW because of the intense ultraviolet radiation produced by the arc?

  1. Clear safety spectacles with side shields only
  2. A welding helmet with a filter lens of the appropriate shade for the current used Correct answer.
  3. A dust mask rated for particulate filtration
  4. A full-face respirator with organic vapor cartridges

Explanation

The GTAW arc emits strong UV and visible radiation that can cause arc flash and eye injury, so a helmet with a properly selected filter shade is required. Clear spectacles alone do not block the radiation. Respirators address airborne contaminants, not optical radiation.

Question 6Workplace safety, health, and environment (OHS) compliance

Before beginning a GTAW task, the welder notices the work lead clamp is loose and the cable insulation is cracked near the connection. What is the correct action?

  1. Wrap the cracked section with tape and continue welding for the remainder of the shift
  2. Increase the gas flow to compensate for the loose connection
  3. De-energize the equipment and have the damaged lead repaired or replaced before welding Correct answer.
  4. Proceed and tighten the clamp with gloved hands while the arc is active

Explanation

Damaged welding leads and poor work connections create shock and fire hazards, so the equipment must be locked out or de-energized and repaired before use. Adjusting a live connection exposes the welder to electric shock. Tape is not an acceptable permanent repair for cracked insulation.

Question 7Workplace safety, health, and environment (OHS) compliance

A welder is setting up a GTAW station on a steel bench. Which grounding practice protects the operator from electric shock?

  1. Rely on the bench's contact with the floor to provide the return path
  2. Ground the torch body to the building's water piping
  3. Connect the work lead to any convenient painted surface of the bench
  4. Attach the work clamp directly to the workpiece or a clean metal surface electrically continuous with it Correct answer.

Explanation

The welding return path must be a solid connection to clean metal so current flows through the intended circuit rather than through the operator or surrounding structures. Painted or loose connections create resistance and stray current. The torch body is not a grounding point and must never be connected to piping.

Question 8Workplace safety, health, and environment (OHS) compliance

During GTAW of stainless steel, the welder notices a yellowish haze and a sharp odor in the breathing zone. What is the most appropriate response?

  1. Lower the amperage until the haze disappears and resume welding in the same position
  2. Position the work so the welder's head stays out of the plume and improve ventilation or fume extraction Correct answer.
  3. Hold the breath until the pass is complete and then step away
  4. Continue welding because the odor indicates the shielding gas is working correctly

Explanation

Stainless steel welding fume can contain hexavalent chromium and other metal oxides, so the welder should keep the head out of the plume and use local exhaust or general ventilation to remove contaminants from the breathing zone. The haze and odor indicate fume is reaching the operator. Breath-holding and amperage changes do not control exposure.

Question 9Workplace safety, health, and environment (OHS) compliance

A welder must join a small aluminum component with GTAW. Which practice best reduces the risk of burns from hot work?

  1. Judge temperature by touching the part briefly with a bare finger
  2. Quench the part in a bucket of water immediately after welding and handle it bare-handed
  3. Mark the part as hot, allow it to cool, and use tongs or heat-resistant gloves when handling Correct answer.
  4. Handle the part with thin cotton gloves right after welding

Explanation

Aluminum conducts heat rapidly and can remain hot enough to cause serious burns long after the arc stops, so parts should be marked, allowed to cool, and handled with tongs or heat-resistant gloves. Bare-hand contact and thin cotton gloves offer no thermal protection. Water quenching creates steam and splashing hazards.

Question 10Workplace safety, health, and environment (OHS) compliance

A welder is preparing to strike an arc with high-frequency start near a flammable solvent storage area. Which hazard control applies?

  1. Move the solvent containers to the other side of the shop and begin welding immediately
  2. Ensure the area is free of flammable vapors and obtain a hot work permit before starting Correct answer.
  3. Increase the shielding gas flow to displace flammable vapors from the work area
  4. Proceed if the solvent containers are closed and the welder wears a respirator

Explanation

High-frequency starting and the welding arc can ignite flammable vapors, so hot work requires a permit and verification that the area is free of combustible atmospheres. Closed containers and respirators do not eliminate ignition risk. Shielding gas does not displace flammable vapors in a way that makes welding safe.

Question 11Workplace safety, health, and environment (OHS) compliance

Which statement correctly describes the fire watch requirement after GTAW hot work is completed?

  1. A fire watch is only required when welding inside a building with a sprinkler system
  2. The fire watch must remain for a specified period after work ends to detect smoldering fires Correct answer.
  3. The fire watch may leave as soon as the arc stops and the torch is set down
  4. The fire watch is unnecessary if the welder checks the area visually before leaving

Explanation

Hot work can leave smoldering material that ignites after the welder leaves, so a fire watch must remain for the period specified by the site's hot work program, commonly at least 30 minutes. The watch is required regardless of sprinklers. A quick visual check by the welder does not replace the watch.

Question 12Workplace safety, health, and environment (OHS) compliance

A welder is using a water-cooled GTAW torch. Which condition indicates the cooling system should be checked before welding continues?

  1. The shielding gas flowmeter reads slightly higher than the set point
  2. The work clamp feels warm to the touch after a long pass
  3. The high-frequency start produces a crisp, consistent arc
  4. The torch body becomes noticeably hot and the coolant flow indicator shows low flow Correct answer.

Explanation

A water-cooled torch depends on continuous coolant flow to remove heat; a hot torch body with low indicated flow signals a cooling fault that can damage the torch and scald the operator. Gas flowmeter readings and arc starting characteristics are unrelated to coolant performance. A warm work clamp reflects current flow, not coolant failure.

Question 13Workplace safety, health, and environment (OHS) compliance

A welder must weld overhead with GTAW. Which precaution most directly protects against burns and fire from falling sparks and hot spatter?

  1. Reduce the shielding gas flow so fewer sparks are produced
  2. Keep the area below clear of people and continue welding without additional protection
  3. Wear a long-sleeved shirt and rely on the helmet to deflect falling material
  4. Use flame-resistant clothing, leather sleeves, and fire-resistant blankets over combustible surfaces below Correct answer.

Explanation

Overhead welding allows sparks and hot metal to fall onto the welder and surrounding surfaces, so flame-resistant clothing, leather protection, and fire-resistant blankets over combustibles are the direct controls. Clearing people from below is necessary but does not protect the welder or combustible materials. Gas flow does not control spark generation.

Question 14Workplace safety, health, and environment (OHS) compliance

Which practice correctly addresses the asphyxiation hazard of argon and helium shielding gases in a poorly ventilated work area?

  1. Monitor oxygen levels and provide ventilation that prevents shielding gas accumulation Correct answer.
  2. Assume the gases are safe because they are inert and do not react with the body
  3. Add a scent to the gas so leaks can be detected by smell
  4. Post a sign warning that the gas is flammable

Explanation

Argon and helium are inert but displace oxygen, creating an oxygen-deficient atmosphere that can cause unconsciousness without warning. The correct control is oxygen monitoring plus ventilation or exhaust at low points where the heavier-than-air gases collect. These gases are not flammable, and odorants are not added.

Question 15Workplace safety, health, and environment (OHS) compliance

A welder is preparing a joint and plans to use a chemical paint stripper before welding. What is the safest sequence?

  1. Apply the stripper only near the weld and leave the residue on the surrounding area
  2. Weld with a slightly longer arc to burn off any remaining stripper
  3. Weld immediately after applying the stripper so the surface does not re-oxidize
  4. Remove the stripper residue completely, allow the part to dry, and verify the surface before welding Correct answer.

Explanation

Paint strippers may contain solvents or chlorinated compounds that decompose into toxic gases when heated by the arc, so all residue must be removed and the part dried before welding. Welding over residue or using a longer arc to burn it off exposes the welder to hazardous decomposition products. Partial application does not eliminate the hazard.

Question 16Workplace safety, health, and environment (OHS) compliance

A welder uses a foot pedal to control current during GTAW. Which practice reduces the risk of an electrical incident with the pedal and its cable?

  1. Inspect the pedal cable for damage and keep it clear of water, hot metal, and traffic paths Correct answer.
  2. Place the pedal on a wet floor to improve electrical contact
  3. Route the pedal cable across a walkway to keep it away from the work area
  4. Coil the pedal cable tightly around the welding machine while in use

Explanation

Foot pedal cables carry control voltage and can be damaged by hot metal, water, or being run over, so they must be inspected and routed clear of such hazards. Running cables across walkways creates trip and damage risks. Wet floors and coiling cables around the machine increase electrical and damage hazards.

Question 17Workplace safety, health, and environment (OHS) compliance

A welder is assigned to GTAW on a part that has been degreased and is still wet with solvent. Which statement best describes the correct action?

  1. Begin welding since the solvent will evaporate in the arc
  2. Wait until the part is completely dry and confirm no solvent residue remains before welding Correct answer.
  3. Increase the shielding gas flow to dilute the solvent vapors
  4. Wipe the part once with a rag and begin welding immediately

Explanation

Residual solvent, especially chlorinated degreasers, can decompose into toxic gases under arc heat and UV, and moisture can cause porosity. The part must be fully dry and free of residue before welding. A single wipe may not remove residue, and gas flow does not neutralize decomposition products.

Question 18Workplace safety, health, and environment (OHS) compliance

A shop uses a shared GTAW station. Which control best prevents inadvertent energization of the machine while a welder is replacing a damaged torch cable?

  1. Wear insulating gloves and work quickly to limit exposure
  2. Ask a coworker to watch the machine and warn anyone who approaches
  3. Turn the machine's current dial to zero and proceed with the repair
  4. Apply lockout/tagout to the machine's power source before beginning the repair Correct answer.

Explanation

Lockout/tagout isolates the energy source and prevents another worker from energizing the equipment while a repair is in progress. Turning the dial to zero does not remove electrical energy from the machine. A coworker's warning and insulating gloves are not positive isolation controls.

Question 19Workplace safety, health, and environment (OHS) compliance

A welder is working in a shop where several GTAW stations share a ventilation system. Which observation most strongly indicates the ventilation is inadequate for the current workload?

  1. The work clamp is securely attached to clean metal
  2. The shielding gas flowmeter reads within the specified range
  3. The welder reports headaches and dizziness that improve after leaving the area Correct answer.
  4. The arc starts reliably with high frequency

Explanation

Symptoms such as headache and dizziness that resolve when the worker leaves the area suggest exposure to welding fume, ozone, or oxygen deficiency and point to inadequate ventilation. Gas flow, arc starting, and work clamp condition are unrelated to ventilation performance. Symptom reports should trigger air monitoring and corrective action.

Question 20Workplace safety, health, and environment (OHS) compliance

During a GTAW operation, a welder notices the argon cylinder regulator shows a sudden drop in delivery pressure while the cylinder valve is fully open. Which action is most appropriate?

  1. Shut the cylinder valve, isolate the regulator, and inspect for a leak or faulty regulator before continuing Correct answer.
  2. Spray soap solution on the regulator while welding continues to locate the leak
  3. Increase the current to compensate for the reduced gas flow
  4. Continue welding and adjust the flowmeter to maintain the desired reading

Explanation

A sudden drop in delivery pressure with the valve open suggests a supply or regulator fault that could leave the weld unprotected and may indicate a leak. The safe response is to close the valve, isolate the regulator, and inspect or replace faulty components. Adjusting the flowmeter or current does not correct the underlying fault, and leak testing while welding is unsafe.

Question 21Interpretation of welding drawings, symbols, and specifications

In a welding symbol, the reference line is drawn horizontally. What does a tail placed at the far right of the reference line contain?

  1. The number of passes required
  2. The root opening dimension in millimetres
  3. The electrode diameter used for the root pass
  4. The specification, process, or procedure reference for the joint Correct answer.

Explanation

The tail of a welding symbol is the optional fork at the end of the reference line reserved for supplementary information such as the welding process, a procedure specification number, or a standard reference. Dimensions such as root opening and groove angles belong on the symbol itself, not in the tail.

Question 22Interpretation of welding drawings, symbols, and specifications

A fillet weld symbol shows the size 6 mm placed on the left side of the triangle. What does this placement indicate?

  1. A 6 mm leg length on the arrow side of the joint Correct answer.
  2. A 6 mm throat on both sides of the joint
  3. A 6 mm weld length in 100 mm increments
  4. A 6 mm root gap to be maintained during fit-up

Explanation

For a fillet weld, a size shown to the left of the weld symbol denotes the leg dimension of the weld. Because the triangle sits on the solid side of the reference line, the weld is placed on the arrow side of the joint.

Question 23Interpretation of welding drawings, symbols, and specifications

On a groove weld symbol the arrow points toward the member that is to be prepared with a bevel. Which symbol element confirms the bevel is on the arrow side?

  1. The groove symbol drawn above the reference line
  2. The groove symbol drawn below the reference line Correct answer.
  3. The tail letter designation
  4. The all-around circle at the symbol junction

Explanation

The reference line has two sides: the solid line side and the dashed line side. A weld symbol placed on the solid line side, which is the side the arrow points toward, means the weld is made on the arrow side of the joint.

Question 24Interpretation of welding drawings, symbols, and specifications

A welding symbol carries a circle at the junction of the reference line and the arrow. What does this circle require the welder to do?

  1. Weld all around the joint Correct answer.
  2. Weld only the arrow side
  3. Weld in the field at the installation site
  4. Weld with a backing ring

Explanation

The circle at the junction of the arrow and reference line is the weld-all-around symbol, meaning the weld is to be made continuously around the entire joint. It is distinct from the field weld flag, which is a small flag on the reference line.

Question 25Interpretation of welding drawings, symbols, and specifications

A small flag is attached to the reference line of a welding symbol. What does the flag tell the fabricator?

  1. The weld requires a backing gas purge
  2. The weld is a temporary tack weld
  3. The weld must be inspected by radiography
  4. The weld is to be made in the field rather than in the shop Correct answer.

Explanation

The flag on the reference line is the field weld symbol, indicating the weld is performed at the installation site rather than in the fabrication shop. Shop drawings often use it to separate field erection work from shop work.

Question 26Interpretation of welding drawings, symbols, and specifications

A groove weld symbol includes the letters 'CJP' written in the tail. What does this abbreviation specify?

  1. Chamfered joint preparation is required
  2. Complete joint penetration is required Correct answer.
  3. Continuous joint pass is required
  4. Concave joint profile is required

Explanation

CJP stands for complete joint penetration, meaning the weld must fuse through the full thickness of the joint. It is a strength-critical requirement and is usually verified by the procedure and inspection method stated in the WPS.

Question 27Interpretation of welding drawings, symbols, and specifications

A drawing shows a groove weld symbol with a rectangle placed in the root opening area of the symbol. What does this rectangle indicate?

  1. The joint requires preheat
  2. A seal weld must be applied first
  3. The weld must be ground flush
  4. A backing or root support is required Correct answer.

Explanation

A rectangle drawn in the groove of the weld symbol indicates that backing or root support is used. The letter inside or a nearby note usually identifies whether the backing is removable or permanent.

Question 28Interpretation of welding drawings, symbols, and specifications

A welding symbol shows a number to the right of the fillet weld symbol in the form 50-200. How should the welder interpret this?

  1. Weld size 50 mm applied over a 200 mm length
  2. Weld 50 passes over a 200 mm section
  3. Weld length 50 mm with a pitch of 200 mm between weld increments Correct answer.
  4. Weld length 200 mm with a 50 mm root gap

Explanation

When length and pitch are both given, the length appears first and the pitch, the distance between the starts of successive increments, follows after a dash. This designates an intermittent fillet weld, either chain or staggered depending on symbol placement.

Question 29Interpretation of welding drawings, symbols, and specifications

On a drawing, the weld symbol is placed on the dashed line side of the reference line. What does this mean for the welder?

  1. The weld is made on the other side of the joint from the arrow Correct answer.
  2. The weld is optional at the fabricator's discretion
  3. The weld must be made with a backing plate
  4. The weld is made on the arrow side of the joint

Explanation

The dashed line side of the reference line designates the other side of the joint, opposite the arrow. When the symbol is on the dashed side, the welder prepares and welds the far member.

Question 30Interpretation of welding drawings, symbols, and specifications

A groove weld symbol has a flat line drawn above the arc of the symbol. What does this finishing symbol require?

  1. The weld is to be peened after welding
  2. The weld is to be chipped and brushed only
  3. The weld is to be left with a convex reinforcement
  4. The weld face is to be finished flush with the base metal surface Correct answer.

Explanation

A straight finish symbol placed above the weld symbol means the weld face must be made flush with the surface of the base metal. A curved symbol would indicate a convex or concave profile instead.

Question 31Interpretation of welding drawings, symbols, and specifications

A drawing calls out a 'double-bevel groove weld' with the symbol above and below the reference line. What does the double designation require?

  1. Two passes in the same groove
  2. Two separate welders working simultaneously
  3. A single bevel with a backing strip on the far side
  4. Groove preparation on both members with welding from both sides Correct answer.

Explanation

The double-groove symbol means the joint is prepared on both members and welded from both sides. This is common on thicker plate where welding from one side only would not achieve full penetration.

Question 32Interpretation of welding drawings, symbols, and specifications

A drawing note states 'E7018' alongside the electrode specification on the WPS. In this classification, what does the '1' after the '70' indicate?

  1. The welding position capability of the electrode Correct answer.
  2. The current polarity required
  3. The coating type of the electrode
  4. The minimum tensile strength in ksi

Explanation

In the AWS electrode classification for covered electrodes, the digits after the strength designation encode position and coating/current. The position digit indicates whether the electrode is suitable for all positions or flat and horizontal only.

Question 33Interpretation of welding drawings, symbols, and specifications

A drawing specifies a 'square butt' joint for 3 mm sheet but the WPS calls for a root gap of 1.5 mm. What does the square butt symbol without a root opening dimension imply?

  1. The joint edges are butted with no root opening specified by the symbol Correct answer.
  2. The joint requires a single-V preparation
  3. The joint requires a backing strip
  4. The joint is welded from one side only

Explanation

A square groove symbol alone indicates square-edged members butted together; if a root gap is required it must be shown as a dimension in the symbol or specified in the WPS. The welder should follow the WPS when the drawing is silent on the gap.

Question 34Interpretation of welding drawings, symbols, and specifications

A drawing uses a 'staggered intermittent' fillet weld symbol with the two symbols offset from each other. What does this arrangement specify?

  1. Welds that are staggered in size along the length
  2. Continuous welds on both sides of the joint
  3. Intermittent welds on one side only
  4. Intermittent welds on both sides that alternate along the joint Correct answer.

Explanation

Staggered intermittent symbols place the two fillet symbols on opposite sides of the reference line and offset them, meaning the increments alternate along the joint. Chain intermittent welds would be shown aligned opposite each other.

Question 35Interpretation of welding drawings, symbols, and specifications

A welding symbol shows '3' inside a small triangle placed at the arrow of a groove weld. What does this number represent?

  1. The preheat temperature in hundreds of degrees
  2. The number of passes required
  3. The depth of groove preparation Correct answer.
  4. The root face thickness

Explanation

A number placed inside the groove symbol indicates the depth of preparation or groove depth for that joint. It tells the fitter how deep the bevel or groove must be machined before welding.

Question 36Interpretation of welding drawings, symbols, and specifications

A drawing shows a weld symbol with a concave finish symbol over a fillet weld. What does the concave profile require?

  1. The weld is to be built up above the surface
  2. The weld face is to be dressed to a concave contour Correct answer.
  3. The weld is to be ground flush on the arrow side only
  4. The weld is to be left as-welded

Explanation

A concave finish symbol requires the weld face to be dressed to a concave profile, usually to reduce stress concentration at the toe. This is common on fillet welds subject to fatigue loading.

Question 37Interpretation of welding drawings, symbols, and specifications

A drawing's title block lists 'AWS D1.1' as the governing code and the WPS cites the same code. What is the welder's obligation when the drawing and the WPS appear to conflict on a joint detail?

  1. Choose whichever detail is easier to execute
  2. Stop and request clarification from the responsible engineer before welding Correct answer.
  3. Follow the WPS because it is the more detailed document
  4. Follow the drawing because it always overrides the code

Explanation

When documents conflict, the welder must not guess; the correct action is to stop and seek clarification through the responsible engineer or welding supervisor. The hierarchy of documents is defined by the contract and code, but resolution is a controlled engineering decision.

Question 38Interpretation of welding drawings, symbols, and specifications

A drawing shows a 'back weld' symbol, which is a weld symbol placed on the opposite side of the reference line with the arrow pointing through the joint. How does a back weld differ from a backing weld?

  1. A back weld is applied only to fillet joints
  2. A back weld is made after the root pass is completed on the far side Correct answer.
  3. A back weld is a temporary weld removed later
  4. A back weld is made before the root pass on the far side

Explanation

A back weld is deposited on the reverse side after the front side has been welded, whereas a backing weld is deposited on the reverse side before the front side. Both are shown on the opposite side of the reference line but are sequenced differently.

Question 39Interpretation of welding drawings, symbols, and specifications

A drawing uses an 'all-around' circle on a pipe joint symbol and also shows a field weld flag. What combined requirement does this impose?

  1. The weld is made continuously and then stress-relieved on site
  2. The weld is made on one side only and inspected in the shop
  3. The weld is made in the shop and then inspected in the field
  4. The weld is made continuously around the joint and performed at the installation site Correct answer.

Explanation

The all-around circle requires the weld to be continuous around the entire circumference, and the flag requires that work to be done in the field. Both symbols are read together on the same reference line.

Question 40Interpretation of welding drawings, symbols, and specifications

A drawing dimension shows a groove angle of 60 degrees on a single-V butt joint. How is this angle measured and what does it govern?

  1. The angle of the root face to the vertical
  2. The angle of the electrode to the joint
  3. The bevel angle of one face measured from the plate surface
  4. The included angle between the two bevel faces, governing the groove opening Correct answer.

Explanation

The groove angle is the total included angle between the prepared faces of a V groove, so each bevel face is half of that value. It governs the opening the welder must fill and is distinct from the bevel angle of a single face.

Question 41Preparation of materials, tools, equipment, and work area

A GTAW welder must join 6 mm thick austenitic stainless steel plate. Which shielding gas composition is the standard choice for this work?

  1. Pure argon Correct answer.
  2. Argon with 2% oxygen
  3. Argon with 25% helium
  4. Carbon dioxide

Explanation

Austenitic stainless steel is normally welded with pure argon for GTAW because argon gives a stable arc, good cleaning action and adequate penetration at this thickness. Adding oxygen is avoided since it can oxidize the weld and damage the tungsten electrode.

Question 42Preparation of materials, tools, equipment, and work area

Before striking an arc on a new piece of mild steel plate, the welder wipes the surface with acetone. What is the main purpose of this step?

  1. To cool the plate to room temperature
  2. To create a protective oxide layer for the weld
  3. To remove oil, grease and moisture that cause porosity Correct answer.
  4. To increase the electrical conductivity of the plate

Explanation

Solvent wiping removes hydrocarbons and moisture that would break down in the arc and introduce porosity and erratic arc behavior. Clean surfaces are a prerequisite for sound GTAW welds because the process has no flux to absorb contaminants.

Question 43Preparation of materials, tools, equipment, and work area

Which tungsten electrode color code identifies 2% thoriated tungsten in the AWS classification system?

  1. Green
  2. Purple
  3. Grey
  4. Red Correct answer.

Explanation

In the AWS color-coding system, red identifies EWTh-2, the 2% thoriated electrode. Thoriated tungsten offers good arc starting and current-carrying capacity, though its radioactive content requires handling controls.

Question 44Preparation of materials, tools, equipment, and work area

A welder is preparing to weld 3 mm aluminum sheet in AC GTAW. Which electrode tip preparation is appropriate?

  1. A sharp 60-degree taper
  2. A rounded, slightly blunted tip Correct answer.
  3. A pointed tip with a 15-degree included angle
  4. A flat truncated tip with no taper

Explanation

For AC welding of aluminum, the electrode is typically given a rounded or slightly blunted tip so it can form a stable ball without excessive erosion. A sharp taper tends to melt back and contaminate the weld with tungsten.

Question 45Preparation of materials, tools, equipment, and work area

When grinding a tungsten electrode, which practice produces the best arc stability?

  1. Grinding across the electrode axis with a coarse wheel
  2. Grinding parallel to the electrode axis with a dedicated fine wheel Correct answer.
  3. Breaking the tip by hand to create a natural point
  4. Cutting the tip with side cutters and dressing with a file

Explanation

Grinding longitudinally along the electrode axis with a fine dedicated wheel produces straight scratch marks that help the arc start consistently and stay stable. Grinding across the axis leaves circumferential grooves that scatter the arc.

Question 46Preparation of materials, tools, equipment, and work area

A welder needs to set up a GTAW station for DCEN welding of carbon steel. Which torch connection arrangement is correct?

  1. Torch on AC, ground clamp on DC positive
  2. Torch on the negative terminal, ground clamp on positive Correct answer.
  3. Torch on the positive terminal, ground on negative
  4. Torch on positive, ground clamp on AC

Explanation

DCEN (direct current electrode negative) places the torch on the negative terminal and the work clamp on positive, concentrating heat in the workpiece and protecting the tungsten. This is the standard polarity for welding carbon steel, stainless steel and most other metals in GTAW.

Question 47Preparation of materials, tools, equipment, and work area

Which filler metal classification is commonly matched to 304 stainless steel base metal for GTAW?

  1. ER4043
  2. ER308L Correct answer.
  3. ER5356
  4. ER70S-6

Explanation

ER308L is the standard filler for welding 304 stainless steel because its composition matches the base metal and its low carbon content limits carbide precipitation. Matching filler to base metal chemistry preserves corrosion resistance in the joint.

Question 48Preparation of materials, tools, equipment, and work area

A welder is preparing to weld thin aluminum sheet in AC GTAW and needs to choose the correct current setting. Which statement best describes the role of AC in this setup?

  1. AC eliminates the need for a shielding gas
  2. AC provides only cleaning action and no penetration
  3. AC alternates between cleaning half-cycles and penetration half-cycles Correct answer.
  4. AC allows the use of a smaller electrode than DCEN at the same current

Explanation

In AC GTAW, the electrode-positive half-cycle breaks up the surface oxide (cleaning), while the electrode-negative half-cycle provides penetration and limits heat at the tungsten. The balance between these halves is what makes AC suitable for aluminum.

Question 49Preparation of materials, tools, equipment, and work area

Before welding, a welder checks the work lead and torch cable for damage. Which condition most directly creates a safety hazard during GTAW?

  1. A work clamp attached to a clean, bare metal surface
  2. A torch with a new ceramic cup installed
  3. A slightly frayed cable jacket exposing the copper conductor Correct answer.
  4. A cable that is coiled loosely on the floor

Explanation

Exposed conductors in the work lead or torch cable can cause electric shock and arcing to nearby grounded metal. Damaged insulation must be repaired or the cable replaced before welding begins.

Question 50Preparation of materials, tools, equipment, and work area

A welder is preparing a butt joint in 6 mm carbon steel plate for GTAW. Which edge preparation is normally required?

  1. A double-U groove with zero root face
  2. A J-groove prepared on one side only
  3. A single-V groove with a root face and root gap Correct answer.
  4. Square edges with no gap

Explanation

For 6 mm plate, a single-V groove with a root face and root gap provides adequate access for full penetration while controlling weld volume. Square edges would not allow reliable penetration at this thickness without excessive current.