Mixed Deck — All SAW Topics Flashcards

A weld made on HY-80 steel using SAW fails a Charpy impact test at the required temperature. The WPS-specified flux and wire were used correctly. What metallurgical factor should be investigated?

Answer: Interpass temperature exceeding the maximum allowed value

Excessively high interpass temperatures coarsen the heat-affected zone and weld metal microstructure, significantly reducing Charpy impact toughness in quenched-and-tempered steels.

Which non-destructive test is commonly used to detect internal weld defects?

Answer: Radiographic testing

Radiographic testing (RT), which uses X-rays or gamma rays, is a widely used non-destructive test method for detecting internal weld defects. It can reveal subsurface discontinuities such as porosity, slag inclusions, lack of fusion, and cracks by producing an image of the weld's internal structure on film or a digital detector. This allows for thorough inspection without damaging the part.

What is the primary reason for using a metal-cored (composite) SAW wire electrode instead of a solid wire?

Answer: To achieve higher deposition rates and incorporate alloying elements impractical in solid wire

Metal-cored wires contain metallic powder fills that increase melt-off rate and allow alloying additions (Ni, Cr, Mo) that cannot be economically drawn into solid wire form, enabling precise weld metal chemistry control.

When performing SAW near combustible materials, the minimum safe clearance distance required is:

Answer: 25 feet (7.6 m)

ANSI/AWS Z49.1 requires a minimum 25-foot (7.6 m) clearance from combustibles, or appropriate fire-resistant shields must be used.

When setting up a SAW machine for a new joint configuration, which parameter should typically be adjusted FIRST?

Answer: Wire feed speed (amperage)

Wire feed speed controls amperage and is the primary variable that determines heat input, so it is set first before fine-tuning voltage and travel speed.

When performing SAW on a large ring gear, the use of run-off tabs at weld end locations primarily prevents:

Answer: Crater cracks and porosity at the weld termination

Run-off tabs allow the crater to form and solidify outside the structural weld, preventing the shrinkage cracking and porosity common at weld stops.

A SAW tractor's engine-driven wire feeder loses consistent wire feed speed as engine RPM fluctuates. The most likely cause is:

Answer: An unstable governor on the engine

Wire feed speed in engine-driven SAW systems is often tied to engine RPM; governor instability causes RPM swings that directly translate to inconsistent wire feed.

In the AWS A5.17 flux-wire classification 'F7A2-EM12K', what does the 'F7' prefix indicate about the weld deposit?

Answer: Minimum tensile strength of 70,000 psi (70 ksi)

In AWS A5.17, 'F7' designates a flux that, when used with the specified wire, produces weld metal with a minimum 70,000 psi tensile strength; the number represents tensile strength in multiples of 10,000 psi.

Which non-destructive testing method is most effective for detecting subsurface lack-of-fusion defects in a SAW weld?

Answer: Ultrasonic testing

Ultrasonic testing can detect internal volumetric and planar defects such as lack of fusion that are inaccessible to surface methods.

Which ventilation configuration is considered MOST effective for controlling fume emissions directly at a SAW torch?

Answer: Local exhaust ventilation (LEV) with capture hood near the weld zone

Local exhaust ventilation captures fumes at the source before they disperse into the worker's breathing zone, making it the most effective control method.

Under EPA's Emergency Planning and Community Right-to-Know Act (EPCRA), what is the reporting trigger for a release of manganese compounds above the reportable quantity?

Answer: Immediately notify the Local Emergency Planning Committee (LEPC) and State Emergency Response Commission (SERC)

EPCRA Section 304 requires immediate notification to the LEPC and SERC when a hazardous substance release exceeds the reportable quantity.

A SAW facility operates in a location with frequent power fluctuations. Which feature in the controller's software configuration best protects against data corruption during updates?

Answer: Uninterruptible Power Supply (UPS) integration with safe-shutdown triggers

UPS integration with safe-shutdown triggers ensures the update process completes or safely aborts before power loss corrupts flash memory.

Which contact tip material is most commonly used in SAW torches handling high current levels above 1000 A?

Answer: Chromium-zirconium copper alloy

Chromium-zirconium copper alloys offer high electrical conductivity combined with superior heat resistance needed at very high amperages.

Which preventive maintenance task specifically helps prevent hydrogen cracking in SAW joints made on high-strength steels?

Answer: Verifying the flux drying oven temperature calibration and rebaking flux to specification

Flux moisture is the primary hydrogen source in SAW; verifying oven calibration and rebaking flux to specified temperatures (typically 500–700°F) ensures diffusible hydrogen remains below critical levels.

In a tandem SAW setup, using DC lead / AC trail configuration primarily helps to:

Answer: Reduce magnetic arc blow while maintaining high deposition rates

The DC lead provides deep penetration while the AC trail reduces magnetic arc blow interference between the two closely spaced arcs.

What happens to weld bead convexity when arc voltage is set too low in SAW?

Answer: The bead becomes high and narrow (ropy)

Low arc voltage produces a short, constricted arc that deposits metal in a high, narrow, ropy bead shape.

During SAW preventive maintenance, the ground connection between the power source chassis and the building ground is found to be loose. What is the correct action?

Answer: Retighten the connection immediately before any further welding operations

A loose chassis ground connection creates a shock hazard because fault currents may flow through the operator instead of the ground path; immediate correction is mandatory.

In a SAW multi-wire system, the trailing electrode is typically connected to:

Answer: AC to reduce arc blow interference between electrodes

The trailing electrode in multi-wire SAW is typically on AC to minimize magnetic arc blow caused by interaction between DC magnetic fields.

Why is documentation important in SAW technology?

Answer: It ensures knowledge transfer, troubleshooting, and operational continuity

Documentation captures configurations and procedures, enabling knowledge transfer and continuity regardless of staff changes.

A SAW technician measures 32V at the power source terminals but only 28V at the work clamp connection. This 4V difference indicates:

Answer: Voltage drop due to resistance in the welding cables and connections

The 4V drop represents resistive losses in the cables and connections between the power source and work, per Ohm's Law (V = IR).