Q1: In continuous casting of liquid steel, the mould is made of

ANS:B - water cooled copper.

In continuous casting of liquid steel, the mould is typically made of water-cooled copper. Explanation:

1. Purpose of the Mould: In continuous casting, the mould is a crucial component of the casting process. It serves to shape the molten steel into a solidified form as it passes through the continuous casting machine.
2. Material Selection: The mould needs to withstand the high temperatures and thermal stresses associated with the continuous casting process. It also needs to provide efficient cooling to facilitate the solidification of the molten steel.
3. Water-Cooled Copper Moulds: Water-cooled copper moulds are commonly used in continuous casting due to their excellent thermal conductivity, high melting point, and resistance to thermal fatigue. Copper has a high thermal conductivity, which allows for efficient heat extraction from the molten steel, promoting rapid solidification and maintaining the desired casting speed.
4. Construction: Water-cooled copper moulds consist of a hollow copper shell with water circulating through internal channels. The water absorbs heat from the molten steel, preventing the mould from overheating and ensuring proper solidification of the steel shell.
5. Advantages: The use of water-cooled copper moulds offers several advantages, including:
   • Efficient cooling, leading to uniform solidification and improved product quality.
   • Extended service life due to copper's resistance to thermal fatigue.
   • Reduced risk of surface defects and internal stresses in the cast product.
6. Alternative Materials: While water-cooled copper is the most common material for continuous casting moulds, other materials such as water-cooled steel and refractory oxide materials may also be used in certain applications. However, water-cooled copper is preferred in many cases due to its superior thermal properties and performance.