AWS Certified Welding Inspector (CWI) — All Questions

In shielded metal arc welding (SMAW), what primarily protects the molten weld pool from atmospheric contamination?

• a.An external supply of inert argon gas
• b.The gaseous shield and slag produced as the flux coating on the electrode burns and melts✓
• c.A granular flux fed continuously from a hopper
• d.A vacuum chamber surrounding the arc

SMAW (stick welding) uses a consumable electrode covered with a flux coating. As the arc heats the coating, it decomposes to create a shielding gas and forms a molten slag that both cover the weld pool, protecting it from oxygen and nitrogen. This is why SMAW needs no external gas bottle. Argon/CO2 shielding gas describes GMAW/GTAW; a granular flux from a hopper describes SAW.

Which welding process uses a non-consumable tungsten electrode and typically an inert shielding gas such as argon?

• a.FCAW (flux-cored arc welding)
• b.SAW (submerged arc welding)
• c.GTAW (gas tungsten arc welding)✓
• d.SMAW (shielded metal arc welding)

GTAW, also called TIG, uses a non-consumable tungsten electrode to establish the arc while filler metal is added separately by hand. Argon or helium shields the pool. It produces high-quality, precise welds and is common on thin material and stainless/aluminum. The other processes all use consumable electrodes or wire that become part of the weld.

A welder deposits weld metal and the joint later cracks along the boundary between the base metal and the weld. This region is best described as the:

• a.Heat-affected zone (HAZ)✓
• b.Root face
• c.Weld reinforcement
• d.Toe of the weld

The heat-affected zone is the base metal adjacent to the weld that did not melt but whose microstructure and properties were altered by the heat of welding. It is often the most metallurgically vulnerable region because rapid heating and cooling can harden it or reduce toughness. The root face is a joint-preparation dimension, reinforcement is excess weld metal, and the toe is where the weld face meets the base metal.

On an AWS welding symbol, information placed on the side of the reference line nearer the reader (below a horizontal reference line) applies to the weld on which side of the joint?

• a.The far side, away from the arrow
• b.Both sides equally regardless of placement
• c.Neither side; it is only supplementary data
• d.The arrow side of the joint✓

In the AWS symbol convention, weld symbols below the reference line specify the arrow side of the joint (the side the arrow points to), while symbols above the line specify the other side. This dual placement lets one symbol describe welds on both sides. Understanding arrow-side versus other-side placement is fundamental to reading drawings correctly.

Incomplete fusion in a weld is best described as:

• a.A gas pocket trapped in the solidifying weld metal
• b.A condition where the weld metal did not coalesce completely with the base metal or with adjacent weld beads✓
• c.Excess weld metal extending above the base metal surface
• d.A crater at the end of the weld bead

Incomplete fusion (lack of fusion) occurs when the molten weld metal fails to fuse with the base metal or preceding passes, leaving an unbonded interface. It typically results from insufficient heat, contamination, or poor technique. It is a serious discontinuity because it creates a plane of weakness. A gas pocket is porosity; excess metal is reinforcement; the depression is a crater.

Which nondestructive testing method can reliably detect internal (subsurface) volumetric discontinuities such as porosity and slag inclusions throughout the thickness of a weld?

• a.Radiographic testing (RT)✓
• b.Liquid penetrant testing (PT)
• c.Magnetic particle testing (MT)
• d.Visual testing (VT)

Radiographic testing passes X-rays or gamma rays through the weld to a film or detector, revealing internal volumetric flaws like porosity and slag as density changes on the image. PT only finds surface-breaking flaws; MT finds surface and slightly subsurface flaws in ferromagnetic material; VT only detects surface conditions. RT and ultrasonic testing are the primary volumetric methods for internal discontinuities.

Liquid penetrant testing (PT) is limited to detecting which type of discontinuity?

• a.Deep internal cracks well below the surface
• b.Discontinuities in any material regardless of surface condition
• c.Discontinuities that are open to the surface being examined✓
• d.Only discontinuities in ferromagnetic materials

PT relies on a liquid dye seeping into flaws by capillary action, then a developer draws it back out to form a visible indication. Because the penetrant must enter the flaw, only discontinuities that break the surface can be detected. Unlike MT, PT works on non-magnetic materials such as aluminum and stainless steel, but it cannot find subsurface flaws.

What is the primary personal-safety hazard associated with the arc rays produced during arc welding?

• a.Ingestion of shielding gas
• b.Excessive audible noise damaging hearing
• c.Contact with high-pressure hydraulic fluid
• d.Intense ultraviolet and infrared radiation that can burn skin and eyes (arc flash / arc eye)✓

The welding arc emits intense ultraviolet and infrared radiation that can cause painful arc eye (photokeratitis) and skin burns similar to severe sunburn. Proper protection includes a welding helmet with the correct shade lens, and covering exposed skin. Adjacent workers must also be shielded. This is one of the most common and preventable welding injuries.

Undercut is a weld discontinuity best described as:

• a.Weld metal that has flowed beyond the weld toe onto unfused base metal
• b.A groove melted into the base metal adjacent to the weld toe and left unfilled by weld metal✓
• c.Rounded cavities caused by trapped gas
• d.A depression at the termination of a weld bead

Undercut is a groove or channel melted into the base metal along the toe or root of a weld that is not filled by weld metal, reducing the effective cross-section and creating a stress riser. It is usually caused by excessive current, incorrect travel angle, or too-fast travel speed. Overflow onto unfused metal is overlap, gas cavities are porosity, and the end depression is a crater.