Q1: Addition of __________ in steel can help in increasing the depth of hardness.

ANS:C - vanadium

Vanadium is a chemical element with the symbol "V" and atomic number 23. It is a transition metal that is commonly used as an alloying element in the production of steel and other metals. Here's a detailed explanation of vanadium:

1. Properties: Vanadium is a hard, silvery-grey metal that is relatively rare in nature. It has a high melting point of 1910°C (3470°F) and is known for its corrosion resistance, high strength, and ability to form hard and stable carbides.
2. Alloying element: One of the primary uses of vanadium is as an alloying element in steel production. When added to steel in small amounts (typically around 0.1% to 0.5% by weight), vanadium improves the mechanical properties of the steel, including its strength, toughness, and wear resistance. Vanadium forms solid solution strengthening with iron and contributes to the formation of fine-grained microstructures in steel, which enhances its strength and hardness.
3. Impact on steel properties:
   • Strength: Vanadium increases the strength of steel by forming vanadium carbides, which act as obstacles to the movement of dislocations within the steel matrix. This leads to improved tensile strength, yield strength, and fatigue resistance of the steel.
   • Toughness: Vanadium refines the grain structure of steel, resulting in finer and more uniform grains. This refinement improves the toughness and impact resistance of the steel, making it less prone to brittle fracture.
   • Hardness: Vanadium contributes to the formation of hard and wear-resistant carbides in steel, which increases its hardness and resistance to abrasion and wear.
4. Applications: Vanadium-alloyed steels are used in a wide range of applications where high strength, toughness, and wear resistance are required. These include applications in the aerospace industry (e.g., aircraft components, rocket casings), automotive industry (e.g., engine components, gears, crankshafts), tool and die making (e.g., cutting tools, dies, drills), and construction industry (e.g., high-strength structural components, reinforcing bars).
5. Other uses: Besides steel production, vanadium is also used in other applications such as in the production of superalloys for jet engines, in the manufacture of catalysts for chemical reactions, and in the production of batteries (specifically vanadium redox batteries) for energy storage.