Carbon Content

As per A515/A515M , Gr 70 mentioned the maximum allowable carbon content for plate over 2 inch is 0.35% , what is the minimum carbon content acceptable for this Grade , this is the first question ?

We have one plate with very very low carbon content around 0.049 % & other element content all with the range of 515 Gr 70 like Si=0.27 , Mn=1.42 , P=0.018 , S=0.005 & Fe=97.9 , plus the Tensile value around 510 N/mm2 .

Can we consider this plate comply with A515/A515M Gr 70 even the carbon content is very low ?

Isn't there a metals forum for this question?

Please do not double post.

There is not a need to post a minimum carbon provided it is a sufficient amount to meet mechanical property requirements. You did not say whether you also met yield and elongation requirements but if you did, then you can be assured there is sufficient carbon in the steel

Lower carbon contents and controlled rolling parameters will provide low temp toughness and meet the minimum tensile properties. I would be concerned if the material would be employed at high temps above 600F.

According to the A515/A515M standard, the maximum allowable carbon content for Grade 70 plate is 0.35%, with no specified minimum carbon content. Although the carbon content of the plate is as low as approximately 0.049%, with other elements meeting the requirements, determining compliance with the standard requires a comprehensive consideration of mechanical performance, chemical composition balance, and processing history.

According to the specifications in A515/A515M for Grade 70, the minimum allowable carbon content is not explicitly mentioned. However, the maximum allowable carbon content for plates over 2 inches is stated as 0.35%.

Having a very low carbon content of around 0.049% in the plate you mentioned is significantly below the maximum limit specified for Grade 70. While the carbon content is below the maximum, it is important to ensure that all other element contents align with the specified ranges for Grade 70, such as Si, Mn, P, S, and Fe, as you have mentioned.

Considering the low carbon content but the alignment of other element contents within the specified ranges for Grade 70, along with a tensile value around 510 N/mm², it is advisable to consult with a materials engineer or a relevant expert to determine if the plate can be considered compliant with A515/A515M Grade 70 standards. The very low carbon content may raise concerns about the material's properties and performance in certain applications, so a thorough evaluation is recommended before making a final determination.