To make the steel hard requires increase in
- AThe quantity of Carbon
- BThe quantity of Manganese
- CThe quantity of Silicon
- DThe quantity of Chromium
Show answer and explanation
Correct answer: (a) The quantity of Carbon
Explanation
The more carbon in steel, the harder (and more brittle) it gets: mild steel has about 0.1–0.3% carbon, tool steels up to about 1.5%.
Other elements change other properties: manganese adds strength and toughness, chromium resists corrosion, silicon improves magnetic properties.