Chemical Composition

[Captainobvious]

I read these forums all the time, and since I now have a question I thought I would post!

As per the ASTM requirement (A961) for forged A350 LF2 Flanges can someone advise me on what variances could be expected between the chemical composition on the certificates issued by the mill, compared with results obtained by undertaking actual product analysis.

Thanks

 

[metengr]

Yes, you need to review ASTM A 751 for product analysis and product analysis tolerances in Table 1 of A 961.

 

[metengr]

Sorry a typo - the previous post should be Table 2 of A 961 for low alloy steel, which is applicable for Grade LF2.

 

[Captainobvious]

Thanks,

I have both the standards you mentioned.

Am I therefore correct in thinking that the results obtained through product analysis in the lab MUST therefore be the same as the mill cert after of course taking into account of the tolerances.

I.e. Mill cert Mn = 1.220. Lab test = 0.940, Tolerance = 0.040, therefore the two do not compare.

I thankyou for you help.

 

[metengr]

The product analysis results from your lab should be within the stated tolerances in Table 2 of A 961. If the mill test report indicates similar product analysis results these results would also be bound to Table 2, not heat analysis results.

 

[Captainobvious]

Ok,

Basically we got some flanges and we have an issue where it may be that the material certs are not representative of the flanges, they originated in China.

We tested a left over sample flange and although the sample was in the spec for A350 LF2 the results are very different from that on the mill cert, thus creating more suspicion that the mill certs may not be as real as we would like to belive

 

[metengr]

Well, this does not surprise me because I have seen some boiler pressure part products from China that the mill certs are no better than toilet paper. Reject them based on your own analysis.

 

[arunmrao]

Mill certs and product analysis differing can also happen due to poor records keeping. If the product analysis satisfies the standards,it will become quite difficult to reject the lot. Apply caution while rejecting in such a case.

Captainobvious,I hope you enjoy the forum for a long time as you have adopted the right approach of observing for a while and then posting ,which is the right way to go.

Learn the rules,so you know how to break them properly.
Dalai Lama

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