Certified Welder Base and Filler Metals 3 — Questions and Answers
Question 1: Which filler metal is preferred when welding austenitic stainless steel to minimize sensitization?
- E308
- E308L (Correct answer)
- E316
- E310
Correct answer: E308L
E308L has a low carbon content (≤0.04%) that reduces carbide precipitation and sensitization in the heat-affected zone.
Question 2: What is the primary purpose of adding silicon (Si) to ER70S-6 wire compared to ER70S-2?
- Increase tensile strength
- Act as a deoxidizer for mildly contaminated base metals (Correct answer)
- Reduce spatter at high voltages
- Improve corrosion resistance
Correct answer: Act as a deoxidizer for mildly contaminated base metals
Higher silicon in ER70S-6 provides stronger deoxidation, making it suitable for welding base metals with rust or mill scale.
Question 3: A base metal identified as ASTM A36 is classified as which type of steel?
- High-alloy steel
- Structural carbon steel (Correct answer)
- Tool steel
- Stainless steel
Correct answer: Structural carbon steel
ASTM A36 is a common structural carbon steel with a minimum yield strength of 36 ksi used in construction.
Question 4: What does 'weldability' of a base metal primarily refer to?
- The metal's tensile strength after welding
- The ease with which a metal can be welded with acceptable properties and without defects (Correct answer)
- The type of shielding gas required
- The preheat temperature needed
Correct answer: The ease with which a metal can be welded with acceptable properties and without defects
Weldability encompasses the metal's ability to be welded under given conditions to produce sound joints meeting service requirements.
Question 5: Chromium-molybdenum (Cr-Mo) alloy steels are commonly used in which application?
- Cryogenic pressure vessels
- High-temperature pressure piping and boilers (Correct answer)
- Marine structures
- Automotive body panels
Correct answer: High-temperature pressure piping and boilers
Cr-Mo steels offer excellent creep resistance and strength at elevated temperatures, making them ideal for boilers and high-pressure piping.
Question 6: When selecting filler metal for a specific base metal, which document provides the primary guidance?
- The welding inspector's log
- The applicable welding procedure specification (WPS) (Correct answer)
- The machine manufacturer's manual
- OSHA 1910.252
Correct answer: The applicable welding procedure specification (WPS)
The WPS specifies the approved filler metal, process, and parameters qualified for a given base metal.
Question 7: Nickel alloy filler metals are used primarily to weld base metals that require which characteristic?
- High hardness
- Excellent corrosion and high-temperature resistance (Correct answer)
- Low cost and easy availability
- High carbon content
Correct answer: Excellent corrosion and high-temperature resistance
Nickel alloys provide outstanding resistance to corrosive environments and maintain strength at high temperatures.
Certified Welder Base and Filler Metals 3
Which filler metal is preferred when welding austenitic stainless steel to minimize sensitization?