Which material is ferrous, very brittle, and hard (wear resistant), used for drill bits and lathe tools?

Which material is ferrous, very brittle, and hard (wear resistant), used for drill bits and lathe tools?

• A. Cast iron
• B. High Speed steel
• C. High Carbon Steel
• D. Mild steel

Answer: (B)

When cutting tools work, they get very hot and wear down the edge quickly. The material chosen for drill bits and lathe tools needs to stay hard and resist wear even at high temperatures. High Speed Steel is an iron-based alloy that includes carbide-forming elements like tungsten and vanadium. These form hard carbides in the structure, giving a edge that stays sharp and wears slowly under heat, which is exactly what cutting tools need. Cast iron is ferrous but brittle, so it lacks the toughness needed for a reliable cutting edge. High carbon steel can be hard but doesn’t retain hardness as well when hot. Mild steel is too soft for cutting tools. So, High Speed Steel is the best match for drill bits and lathe tools.

When cutting tools work, they get very hot and wear down the edge quickly. The material chosen for drill bits and lathe tools needs to stay hard and resist wear even at high temperatures. High Speed Steel is an iron-based alloy that includes carbide-forming elements like tungsten and vanadium. These form hard carbides in the structure, giving a edge that stays sharp and wears slowly under heat, which is exactly what cutting tools need.

Cast iron is ferrous but brittle, so it lacks the toughness needed for a reliable cutting edge. High carbon steel can be hard but doesn’t retain hardness as well when hot. Mild steel is too soft for cutting tools. So, High Speed Steel is the best match for drill bits and lathe tools.