Cutting speed capability — HSS versus carbon steel tools Relative to plain carbon tool steels, high-speed steel (HSS) tools can normally operate at cutting speeds that are:

Introduction / Context:
Tool material choice governs allowable cutting speed before excessive wear or softening occurs. High-speed steel (HSS) retains hardness at higher temperatures than plain carbon tool steel, enabling faster cutting and higher productivity.

Given Data / Assumptions:

• Comparison at similar feeds and depths of cut.
• Uncoated, conventional tools.
• Typical machining of steels.

Concept / Approach:
HSS alloys (with W, Mo, Cr, V, Co) possess improved red hardness and toughness, so they tolerate higher temperatures at the cutting edge. Empirical practice shows HSS speeds are roughly 2–3 times those for carbon tool steels, while cemented carbides and ceramics are higher still.

Step-by-Step Solution:
Identify property difference: HSS has better hot hardness than carbon steel.Relate hot hardness to allowable cutting speed.Choose the realistic multiplier: 2–3 times higher for HSS.

Verification / Alternative check:
Machining handbooks list speed ranges showing HSS significantly above carbon steel, but far below carbides and ceramics.

Why Other Options Are Wrong:
‘‘Lower’’ contradicts HSS advantage; ‘‘5–8’’ or ‘‘8–20 times’’ are more representative of carbide/ceramic jumps over carbon steel, not HSS.

Common Pitfalls:
Assuming coatings or carbide data when the question compares only HSS with carbon tool steel.

Final Answer:
2 to 3 times higher