Question 38 DDE01 - Designated Duty Engineer - Unlimited HP

The Correct Answer is C ### Explanation of Option C (Copper) **Copper** is the recommended metal for fabricating tools used to remove carbon (coke) from precision components like fuel atomizer tips. The primary goal when cleaning atomizers is to remove the hard carbon deposits without damaging the precision-machined orifice, ports, or seating surfaces of the nozzle, which are typically made of steel alloys or brass. Copper is significantly **softer** than the steel of the nozzle and the hardened carbon. A copper tool will wear, deform, or break before it is hard enough to scratch, score, or gauge the critical surfaces of the atomizer. This principle ensures the integrity of the fuel spray pattern, which is vital for efficient combustion. ### Explanation of Incorrect Options **A) Tungsten:** Tungsten (especially tungsten carbide) is extremely hard and highly resistant to abrasion. A tool made of tungsten would easily scratch, gouge, or permanently damage the precision spray orifice and critical internal surfaces of the atomizer, rendering the nozzle useless. **B) Chrome-moly steel (Chromium-molybdenum steel):** This is a high-strength, durable alloy steel. While common in general tooling, chrome-moly steel is too hard to be used safely on precision burner tips. It would risk scratching or deforming the critical metal surfaces of the nozzle, which could destroy the required spray pattern. **D) Titanium:** Titanium, even in its unalloyed state, is often harder than many common steels and certainly harder than copper. A titanium tool would possess sufficient hardness and strength to damage the atomizer components when scraping away hardened carbon.