"Typical" Charpy V Notch results on ASTM A709 Gr. 50

[bulldog2002]

I recently received several plates of ASTM A709, Gr.50, Normalized Rolled steel. The material certs were provided with the steel and Charpy V Notch values were provided from the steel mill on the material certs. The CVN test were performed at -40c, at the mill. The results listed on the material cert were extremely high from what I have ever seen (ranging around 270ft/lbs). Are the results "typical"? What would "typical" CVN results be for ASTM A709, Gr.50, non-normalized plate be?

And yes, I realize all of the above varies from plate to plate and even from mill to mill, this is why I stress "typical" CVN results.

 

[metengr]

This material could be supplied as a quenched and tempered, HSLA (high strength low alloy steel plate), so yes, the values can be high, especially if the carbon is on the lower end of 0.23% max mass content, and this material is made using a fine grain practice.

Also, what is the reported orientation of the CVN specimens?

 

[bulldog2002]

Metengr, thank you for your comments.

Per the material certification the direction was H-L. Also per the material cert, the carbon content is only .07, with an overall carbon equivalence of .34.

 

[metengr]

bulldog2002;
The major influence on CVN impact energy is carbon content for steel. The lower the carbon content, the lower the ductile to brittle transition temperature along with higher upper shelf CVN impact energy values.

Since you confirmed my suspicion as this being a HSLA steel and is probably fine grained and Q&T, the CVN numbers make sense.

 

[TVP]

bulldog2002,

I would not consider CVN of 270 ft lbs at -40 C to be typical for Grade 50 ASTM A709. Perhaps for Grade 50W Type A, but not standard Grade 50. The standard Grade 50 will only be normalized or TMCP rolled, and does not contain the alloy elements (Cr, Ni, Mo) that Grade 50W Type A does, so the CVN will be lower, especially at - 40 C. Figure 2.3.1 from the following link shows typical results for Grade 50 (50W on the graph) and Grade 50W Type A (HPS-70W):

http://www.fhwa.dot.gov/bridge/guide02.htm

 

[metengr]

Agree with TVP, which is the reason I mentioned in my second post that the HSLA version (Grade 50W) may have been supplied. If the carbon content by mass is only 0.07% you do not have Grade 50, most likely it is HSLA, Grade 50W, Q&T. Check if a substitution was made by the supplier, because Grade A 709 Grade 50W can be supplied under A 588, as Grade A.

 

[bulldog2002]

Gentlemen, Thank you both for your input, I am learning alot. If this helps, the exact Specification on the material cert is: ASTM A572 Grade 50-07/A709 Grade 50-10, Normalized Rolled, .10max C. I know what the ASTM 572, ASTM A709 and the grade 50's mean but I do not know what the -07 and -10 mean? Will those impact the CVN values by putting the steel in a HSLA category?

 

[metengr]

bulldog2002;
The prefix on each ASTM specification above following the Grade designation refers to the revision or adoption of the standard used to manufacture the steel.

What you have been supplied is a material that meets both ASTM specifications and is a HSLA steel meeting Grade 50 or 50W. This would confirm the exceptional CVN impact values.

 

[bulldog2002]

Thank you Metengr, once again I do appreciate your help/knowledge.

 

[stanweld]

bulldog2002,
Plate steels with the Grade 50 chemistry with high Mn:C ratio and having low P & S and Columbium/Niobium + Vanadium contents defined in Type 3, normalized could achieve the absorbed energy values defined on the MTR without thermo-mechanical processing. While not considered typical, these values were achieved on similar steels manufactured as early as the mid-to-late 1970's.

It would be interesting to know the full chemistry of your material.