What percentage of carbon produces the strongest plain carbon steel

[Tiberious]

Homework Statement

[/B]
(a) What percentage of carbon produces the strongest plain carbon steel?

The Attempt at a Solution

I've been posed with the above question and it has lead to some confusion. What is meant by 'strongest'. The question seems to leave open to interpretation what the reader considers to be 'strong' traits of a material. I assume it refers to hardest ? or does it mean the most useable plain carbon steel for mechanical work, so, something with a grain structure near the Eutectoid point on the iron-carbon phase diagram.

Any assistance is appreciated.

 

[Dr.D]

This question is about as nebulous as the worst I have ever seen. The OP put his finger on it: "What is meant by strongest?"

That would be
supporting the maximum static load?
supporting the largest impact load?
at what temperature?
strongest in high-cycle fatigue?
strongest in low-cycle fatigue?
strongest in bending?
strongest in torsion?
etc, etc.

It really does not mean anything at all.

 

[Tiberious]

I've had a discussion with the tutor and this question is supposed to be posed around the question previous. (eutectoid point) on the iron-carbon phase diagram. From what I understand the pearlite (ferrite-cementite) picture would be more useful for mechanical work. I assume this is what the question requires. Any idea towards what I should include in the scope of the answer?