More Questions from Production Engineering

Tool material characteristics Carbon tool steels exhibit low heat resistance and low wear resistance compared with HSS and carbides. Is this statement correct?

Mechanical Engineering Production Engineering Difficulty: Easy
Choose an option
  • A
    Correct
  • B
    Incorrect
  • C
    Correct only for interrupted cuts
  • D
    Incorrect for low-speed turning
  • E
    Correct only above 800 °C

Answer

Correct Answer: Correct

Explanation

Introduction / Context:Tool material selection balances hot hardness, wear resistance, toughness, and cost. Carbon tool steels were historically common but are now limited to low-speed applications due to poor hot-strength and rapid softening at modest temperatures.

Given Data / Assumptions:

  • Carbon tool steels lose hardness rapidly above roughly 200–250 °C.
  • Comparators: high-speed steel (HSS), cast/cemented carbides, ceramics.
  • Operations: general cutting where heat generation is significant.

Concept / Approach:Hot hardness describes a material's ability to retain hardness at elevated temperatures. Carbon tool steels temper easily and cannot maintain an edge under modern cutting speeds, leading to accelerated flank wear and built-up edge formation.

Step-by-Step Solution:

Assess heat resistance: carbon tool steels soften at relatively low temperatures → low heat resistance.Assess wear resistance: softening plus limited alloy carbides → poorer wear resistance than HSS/carbides.Conclusion: the statement is correct.

Verification / Alternative check:Tool life curves (Taylor's equation) show dramatically lower permissible cutting speeds for carbon steels versus HSS/carbide for the same life.

Why Other Options Are Wrong:Claiming incorrectness or exceptions (interrupted cuts, high temperatures) misunderstands the fundamental deficiency in hot hardness and wear resistance.

Common Pitfalls:Using carbon tool steel where heat cannot be controlled; choose HSS or carbide for sustained industrial speeds.

Final Answer:

Correct

Discussion & Comments
No comments yet. Be the first to comment!
Join Discussion