All CWI practice questions
CWI Cutting practice questions
Oxyfuel, plasma arc and air carbon arc cutting and gouging: principles, settings, cut quality and common defects. This domain is about 2% of the exam. Try each question, then open the answer.
Question 1
Why can't stainless steel be cut efficiently by conventional oxyfuel cutting?
- It is not magnetic
- Its chromium forms a refractory oxide that resists the oxidation reaction
- It melts at a much higher temperature than carbon steel
- It conducts electricity too well
Show answer
Answer: B. Its chromium forms a refractory oxide that resists the oxidation reaction
Chromium oxide melts far above the base metal and does not flow away, blocking further oxidation. Plasma arc cutting, flux injection or powder cutting are used instead.
Source: AWS Welding Handbook, 9th ed., Vol. 2 (Welding Processes, Part 1), chapters on thermal cutting (oxyfuel cutting limitations)
Question 2
Which polarity is normally recommended for air carbon arc gouging of carbon steel with DC-coated electrodes?
- DCEP
- DCEN
- AC with uncoated electrodes
- Polarity has no effect
Show answer
Answer: A. DCEP
DCEP with copper-coated electrodes is the usual setup for gouging carbon steel. It gives a stable arc and clean gouge.
Source: AWS Welding Handbook, 9th ed., Vol. 2 (Welding Processes, Part 1), chapters on thermal cutting (air carbon arc cutting)
Test yourself under exam conditions
The free diagnostic mixes every domain at the real exam's weights and scores you by domain. No account needed.