Q1: Broaching tools are usually made of

ANS:B - high speed steel

Broaching tools are usually made of high speed steel. Explanation:

1. High Speed Steel (HSS): High speed steel is a type of tool steel that is highly resistant to wear and retains its hardness at elevated temperatures, making it suitable for cutting operations at high speeds. Broaching involves a continuous cutting action over a long surface, which subjects the tool to high temperatures and wear. HSS tools can withstand these conditions while maintaining their cutting edge sharpness and durability.
2. Characteristics: High speed steel possesses excellent hardness, toughness, and wear resistance properties, making it ideal for machining applications where tools are subjected to high temperatures and mechanical stresses. It can retain its hardness even at temperatures up to 600°C (1112°F), allowing it to maintain cutting efficiency during prolonged use.
3. Suitability for Broaching: Broaching is a machining process that involves cutting a workpiece with a toothed tool in a linear motion. HSS tools are well-suited for this application due to their ability to withstand the continuous cutting action and maintain sharp cutting edges throughout the process. Additionally, HSS tools can be easily sharpened or reconditioned, extending their service life.
4. Alternative Materials: While materials such as tungsten carbide and cermet can also be used for broaching tools, high speed steel remains a popular choice due to its balanced combination of hardness, toughness, and cost-effectiveness. Tungsten carbide and cermet tools may offer superior wear resistance but can be brittle and less suitable for heavy-duty cutting operations like broaching.