Base and Filler Metals Flashcards
7 cards from real Certified Welder practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Base and Filler Metals flashcards as text
What is the significance of the 'F' number system in AWS D1.1 and ASME Section IX for filler metals?
Answer: It groups filler metals with similar usability characteristics for welder qualification purposes
The F-number groups filler metals so that a welder qualified with one F-number may weld with other filler metals in the same group.
Intergranular corrosion in stainless steel welds is most often caused by which condition?
Answer: Sensitization — chromium carbide precipitation at grain boundaries
When stainless steel is held in the 425–870°C range, chromium migrates to grain boundaries as carbides, depleting the surrounding metal of corrosion resistance.
Which characteristic of copper alloys makes them difficult to weld with high heat input?
Answer: Very high thermal conductivity causing rapid heat dissipation
Copper's thermal conductivity is about 6 times that of carbon steel, requiring very high heat input or preheating to achieve fusion.
What is 'hot cracking' in a weld, and which metals are most susceptible?
Answer: Cracking at elevated temperatures during solidification, most common in austenitic stainless steel and aluminum
Hot cracking occurs during weld solidification when low-melting constituents form films at grain boundaries, and austenitic SS and aluminum are highly susceptible.
The 'A' number system in ASME Section IX classifies filler metals based on which property?
Answer: Chemical composition of the deposited weld metal
A-numbers group filler metals by the chemical composition of the weld deposit to ensure similar metallurgical properties.
Why must titanium base metal be welded with inert gas shielding on both the front and back (purge) of the weld?
Answer: Titanium absorbs oxygen, nitrogen, and hydrogen above ~260°C, causing severe embrittlement
Titanium is highly reactive at welding temperatures and will absorb atmospheric gases, dramatically reducing ductility and toughness.
What does the term 'matching filler metal' mean in welding?
Answer: A filler whose deposited weld metal has mechanical properties equal to or greater than the base metal
Matching filler metal ensures the weld deposit meets or exceeds the strength and toughness of the base metal being joined.