case-hardening C-1018 versus A36

[Bob_3]

Would there be a difference in hardening response to nitride case-hardening C-1018 versus A36?
C1018 has a carbon range of .14-.18% whereas A36 is < .25%.

Thanks...

 

What are the actual compositions? Two random samples might be closely overlapping or be quite different, in either composition or mechanicals.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Bob_3]

Here's the compositions I found:
A36
Carbon, C <= 0.25 %
Copper, Cu 0.20 %
Iron, Fe 98 % As Remainder
Manganese, Mn 1.03 %
Phosphorous, P <= 0.040 %
Silicon, Si 0.28 %
Sulfur, S <= 0.050 %

1018
Carbon, C 0.14 - 0.20 %
Iron, Fe 98.81 - 99.26 % As remainder
Manganese, Mn 0.60 - 0.90 %
Phosphorous, P <= 0.040 %
Sulfur, S <= 0.050 %

Maybe as I write I'm answering my own questions, but it seems to be A36 is more of a commercial grade with minimum alloying limits, whereas C-1018 is more of an engineering grade so the properties and hence performance are more closely controlled. Is this thinking correct?

The qist of my original question is: Would there be a more closely controlled and predictable response to nitride case hardening with C1018, and would it be more random and loosly controlled with A36?
If my line of reasoning is correct, I believe the answer is Yes...correct?

 

I believe you may be overthinking this.
Any particular grade of carbon steel has broad variability in tensile properties between random samples, which has as much to do with processing method (i.e., hot rolled or cold finished) as with composition. These two grades should be indistinguishable in case hardening response. I would pay more attention to surface quality: both roughness and an absence of mill decarburization.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Bob_3]

Thank you for the feedback. Yes, I'd likely overthink it, but I suppose that's what we all do...and why these forums are so nice to have an on-line peer review. But I came here for answers and I got them.
I guess it comes down to the classifying bodies calling essentially the same material both AISI C-1018 and ASTM A36.

Thanks again

 

[dbooker630]

Bob,
For a heat treating application I would source the steel to meet SAE 1018 rather than the ASTM designation. If it was riveting, bolting or welding I see no issue with A36. Yes, you did answer your own question.