Q1: Carbon supply in pack carburising process is in the form of

ANS:A - charcoal

In pack carburizing, the carbon supply is typically in the form of a carbon-rich material that releases carbon into the surface of the metal being treated. Among the options provided:

• Charcoal: This is a common carbonaceous material used in pack carburizing. Charcoal contains carbon and burns slowly, releasing carbon monoxide and dioxide, which react with the metal surface to introduce carbon into it.
• Calcium carbide: While calcium carbide does contain carbon, it's not typically used in pack carburizing processes. Calcium carbide reacts with water to produce acetylene gas and calcium hydroxide and is not suitable for introducing carbon into the metal surface in pack carburizing.
• Hydrocarbon oil: Hydrocarbon oil is not typically used as the carbon supply in pack carburizing. While it contains carbon, its primary purpose in other processes might be as a quenching medium or as a protective atmosphere. It doesn't directly supply carbon for carburizing.
• Graphite: Graphite is a form of carbon and is occasionally used in pack carburizing. It can serve as a carbonaceous material that, when heated, releases carbon into the atmosphere of the pack, facilitating carburizing.