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
Which AWS filler metal classification designates an electrode suitable for welding low-alloy, high-strength steel?
Answer: E7018
E7018 is a low-hydrogen electrode designed for high-strength, low-alloy steels requiring good toughness.
What does the 'R' designation indicate in an ER70S-6 filler wire classification?
Answer: Rod or electrode
The 'R' in ER70S-6 indicates the wire can be used as either a rod or an electrode.
A base metal with a carbon equivalent (CE) above 0.45% typically requires which precaution?
Answer: Preheat before welding
High carbon equivalent increases hardenability and crack risk, so preheating is required to slow the cooling rate.
Which stainless steel series is considered non-hardenable by heat treatment?
Answer: Austenitic (300 series)
Austenitic stainless steels cannot be hardened by heat treatment because they remain face-centered cubic at all temperatures.
When welding dissimilar metals such as carbon steel to stainless steel, which filler metal is most commonly recommended?
Answer: E309L
E309L is formulated for joining dissimilar metals, especially carbon steel to stainless steel, due to its high alloy content.
The mill scale on carbon steel base metal can cause which welding problem?
Answer: Porosity and incomplete fusion
Mill scale traps gases and impedes fusion, leading to porosity and lack-of-fusion defects.
What property of aluminum makes it challenging to weld compared to carbon steel?
Answer: Tenacious oxide layer with a much higher melting point than the base metal
Aluminum oxide melts at ~2050°C while aluminum itself melts at ~660°C, so the oxide must be removed before the base metal can fuse.
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