ASTM A703 Product analysis tolerance

[RAJMETALLURGY]

Dear Sirs,

My reported Aluminium level was 0.032% and we checked from the chemical specimen which was poured from the ladle with spectrometer.
My customer requirement is 0.04% max. Its with in the required limit and we sent the casting.
But my customer was checked the Aluminium level on the casting with portable spectrometer and observed Aluminium value is 0.052% and he is not ready to accept the casting.

Can I do anything with ASTM A703 tolerance calculations.

Please guide me.

 

[metengr]

No. I would have the Purchaser and you select an independent test lab for a final, complete chemical analysis result to disposition the heat (accept or reject).

 

[arunmrao]

As suggested by Metengr, go for a complete chemical analysis from a reputed laboratory to establish your claim.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[EdStainless]

In many ASTM product specs you have to go back to the applicable general spec to see if a product chemistry tol outside the original range is allowed. Some specs don't allow it, and some purchasers don't allow it.
Did you check any product samples?
I would send the original melt sample and a product sample to well accredited lab as my colleges suggest.


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P.E. Metallurgy, Plymouth Tube

 

[RAJMETALLURGY]

We have checked from the test bars after machining, and third party also witnessed and accepted the chemical results. But at customer end they checked on the casting and they found the variation.

 

[Dalinus]

There really could be reported aluminium content in casting if analyzed area sits just under some bigger riser (300+ mm).
Aluminium segregates to areas which solidify last so if it gets enough time there could be easily 0,010-0,020% difference to laddle sample (or even to sample taken from attached test block).

As the others said you have to take the sample from the casting from the same location the customer reported.

Customers which have the limit 0,040% Al often have bad experience with AlN cracks so I understand your customer concern.

 

[arunmrao]

I have a good reference article on embrittlement in steel castings. Perhaps you too may want to refer. It is from FlowServe and authored by William C Banks. Hope you find it useful

Avoiding Aluminum Nitride Embrittlement in
Steel Castings for Valve Components V-Rep 84-1

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[EdStainless]

Which outside lab is your customer using?
They are being unrealistic to expect you to rely on them for the final word on this.


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P.E. Metallurgy, Plymouth Tube

 

[bobjustbob]

I am always suspect of portable chemical analysis. Where they using a portable OES or and XRF like a Niton? Either way surface prep is important. What kind of grinding media was used to prepare the surface?

I would have your customer bring the part to a local third party lab where a sample can be removed for testing on a stationary OES.

 

[arunmrao]

bobjustbob,

I just stay away from portable OES or XRF . I prefer the classic wet analysis method, though this is a rarity now.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[mrfailure]

I hope arunmrao meant reputable lab rather than a reputed one ! Make sure they have A2LA certification for chemistry.

Now, ASTM A703 is the general spec for castings. The product tolerance in that spec for aluminum at specified level is 0.8Al + 0.02; i.e. you can be 0.0232% above the 0.04 maximum or be within tolerance at values up to 0.0632%. I would note the product meets spec using the tolerance band.