Reading 1018 material inspection cert

[bryansonnier]

The main 4 chemicals that everyone cites for 1018 are all within the specification. But they also list a very large number of other chemicals that when combined equal to less that what those same cites list for Fe, if they list at all. Most just say "Remainder". The cites that do list the percent Fe show 98.81-99.something. If I subtract all the chemical percents from the certificate the Fe is 98.5%. I'm thinking i should reject it but we are talking 3 tenths of a percent on an item that say "remainder". Do i reject if it contains anything but the 4 chemicals most sites list?

 

[EdStainless]

Elements not in the required list are not a basis for rejection.
As many as the mill wishes can be reported for information purposes.
There is no Fe limit, it is simply remainder.
What you are doing is nonsensical.

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P.E. Metallurgy, consulting work welcomed

 

[bryansonnier]

The certificate lists maximums for most of the other elements so I assume that if those are at or below those maximums the remainder would still be valid, however for the elements Sn (tin), and Ca (Calcium) there is no limit listed. Now the concentrations shown from the ladle for those 2 elements are 0.9% and 0.07% respectively, which I'm sure has a negligible effect on the material but as no maximum is listed, it could theoretically be 25% of the material, which would change things drastically. I'm guessing this is offset by the material strength requirements which would not be met in that extreme scenario. I guess I'll accept this material as everything that is technically controlled falls within specification.

I get the question was a little awkward but it's only nonsensical if you live this stuff daily. For those of us who don't, a little kindness goes a long way. Thank you for your ??help??.

 

[Tmoose]

I think there is an ASTM Standard that may include limits tramp elements.
I bet that Standard has to be in your Purchase Order to steel store to apply.

Here is a related post from about 5 years ago.

https://www.eng-tips.com/viewthread.cfm?qid=429699

 

[EdStainless]

There are some ASTM specs which give a list of minor elements and impose a maximum total for them.
These specs are uncommon.
Many mills avoid these questions by analyzing for 15-25 elements, but only reporting the ones required in the specification.
In reality there are usually only a few non-required elements that are of interest.
How much of these you end up with depends on the source of the material (melted from scrap, from what industry?) and how it was melted and processed.
Practically speaking what usually limits these is the processability of the alloy.
Some elements are more reactive or volatile than others and these may be able to be removed in production (Zn in steel).
On the other hand, some elements are highly soluble and not very chemically different, and they cannot be removed (Cu in SS).

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P.E. Metallurgy, consulting work welcomed

 

[weldstan]

The tin content is quite high and will adversely affect the material's toughness and indicates a high degree of tin plated steel in the melt scrap. Whether this is a problem in the use of the product cannot be determined.

 

[EdStainless]

weldability might be impacted also.
Of should I say especially the toughness of welds.

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P.E. Metallurgy, consulting work welcomed

 

[weldstan]

Just for my curiosity, what was the S content as the the Ca content may indicate ladle desulphurizing.

 

[MagBen]

Fe percentage is simply a math. Subtracting carbon and Manganese percentages, you get the Fe%. Do not subtract other elements that only have a Max, no min.

Zn and Ca are easy to remove if remelting.

With a high Ca, the S might be very low. Co-curious with weldstan.