🔍 Key Concepts

• water washing procedures for boiler firesides • how mechanical impact of high-pressure water affects metal surfaces • difference between chemical corrosion and mechanical damage

💭 Think About

• When you spray high-pressure water onto hot metal tube and drum surfaces, what kind of physical effect can that cause over time? • Which choice describes a mechanical surface damage effect rather than a thermal or chemical effect? • Think about what happens if scale or soot is blasted off too aggressively—what else might the jet of water start removing?

✅ Before You Answer

• Identify which option is primarily a mechanical damage issue, not chemical or metallurgical. • Eliminate choices that deal with corrosion from chemicals rather than physical impact. • Eliminate choices that describe changes in metal properties (like ductility) rather than surface wear.