A36 mod plate with CE 0.3 to 0.33

[CadChick]

Hi,
I'm new at this forum.
I just have a quick question that someone here might be able to help me.
I have a client that is requesting some A36 Mod plate to have a CE value between 0.3 min to 0.33 max and I'm having no luck finding. I wanted to ask if this plate is something that might be common or if I will have a difficult time finding. The majority of the plate I'm needing is 3/16" thk to 3/4" x 96" x 240". I have ran into a few but they have all been 1/4" x 120" x 240". If anyone can guide me or at least tell me this is nearly impossible, I would really appreciate any advise.

Thanks,
CadChick
Houston, TX

 

[metengr]

The carbon equivalent of 0.3 to 0.33 specified by your client is tight. If you review ASTM A36 for material 3/4" and under in thickness, the carbon content alone can be as high as 0.25% by mass (most carbon would be in the range of 0.18 to 0.20% by mass). Now you throw in some manganese and this could easily put you over 0.40 (based on the standard CE formula of C + Mn/6 + (Cr+Mo+V)/5 + (Ni + Cu)/15. I would go back and ask why such a low limit of CE for A 36, unless they are looking to improve notch toughness.

 

[CadChick]

They are requesting to lower for the following purposes

"These carbon equivalent values dictate lower carbon concentrations to minimize the amount of pearlite formation in the steel and maximize corrosion resistance for the particular environment. These CE values will also offer improved weldability compared to the steels with CE values over the 0.331 threshold."

 

[metengr]

I don't agree with the explanation. Well, keep looking for plate suppliers that offer low carbon A36 plate.

 

[arunmrao]

Agree with metengr. Good Luck in your search for A36 plate with lower Carbon.

 

[weldstan]

Agree with metengr; weldability of 3/4" and under A-36 is not an issue and the reported increased corrosion resistance is theoretical at best. I have seen quite a bit of thin wall (< 5/8") A-36 meeting the requirements in the recent past. As T increases the ability to find A-36 meeting the CE will become increasingly unobtainable.

 

[Guest102023]

I agree the specified range is very tight; in fact I find it bizarre. If you take chemistry at three different locations in the same plate I will wager the actual min/max CE range will be greater than your spec range.

I recently went through a restricted CE exercise with a client; my conclusion was that the specification writer was trying to kill a (potential) high hardness problem three different ways. In other words, extreme overkill by a person unfamiliar with the behaviour or real steel under normal fabrication conditions.

I concur with metengr; the explanation is just silly (actually it sounds like a typical LinkedIn question). Designers looking for impact properties do not spec A36. Your spec writer appears also to be attempting to do ASTM's job by making sure the minimum mechanical properties are met. I recommend two weeks at a spa for this person, without access to a cell phone or metallurgy textbook.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"