Question 50 UFIV02 - Assistant Engineer - UFIV

The Correct Answer is C ### 2. Explanation of Option C (Copper) Option C, **Copper**, is the recommended material for fabricating a carbon removal tool for several critical reasons related to maintaining the operational integrity of the atomizer: 1. **Softness and Ductility:** Boiler atomizers are precision-machined components (often made of hardened steel or high-temperature alloys) with extremely fine orifices. Copper is significantly softer and more ductile than steel. When cleaning, if the copper tool contacts the delicate steel surfaces, the copper material will deform, wear down, or yield *before* the harder steel of the atomizer is scratched, scored, or permanently damaged. 2. **Preventing Orifice Damage:** Scoring or enlarging the atomizer orifice by even a small amount will compromise the spray pattern, leading to poor fuel combustion, flame instability, and potential boiler failure. Using a softer material like copper ensures the precision tolerance of the nozzle is preserved during mechanical cleaning. *** ### 3. Explanation of Incorrect Options **A) Chromoly steel** Chromoly (or chromium-molybdenum steel) is a high-strength alloy steel, often used when high hardness is required. It is significantly harder than copper and comparable to, or harder than, the material used in the atomizer body. Using a chromoly tool would pose a very high risk of scratching, scoring, or permanently deforming the critical passages and the final discharge orifice of the precision atomizer. **B) Tungsten** Tungsten, particularly in the form of tungsten carbide, is one of the hardest materials available. It is commonly used for cutting tools and abrasives. Utilizing tungsten to clean delicate steel components would almost certainly result in the destruction of the atomizer orifice and internal parts upon contact. **D) Titanium** While lighter and corrosion-resistant, commercially utilized titanium alloys generally possess high strength and hardness levels comparable to or exceeding many structural steels. Like steel tools, a titanium tool carries a substantial risk of scoring the precision surfaces of the atomizer, thus compromising the spray pattern and leading to inefficient firing.