Different Chemical Compostion in Cast/Product Analysis

Dear Sir, Mostly cast analysis is done with laboratory equipment which is more accurate than the portable methods often used for product analysis. But there never should be very big differences between both (depending on the amount of the element of interest). If you have elements with a % of 0.010 on its certificate you can easily get deviations of about 10 % when performing a product analysis, when the amount is for example 8 % this 10% is not allowed. In most cast material specifications the differences allowed between the as cast and product analysis are specified. Hope this information is helpful for you.

Thanks Mr Hpi 001

The simple answer is inter-instrument and inter laboratory error coupled with potential segregation in the wrought product.

Plus the fact that some elements segregate during solidification, and some even can segregate in the ladle during the teeming or casting.

Obviously better technology melt shops and casters will have less of a difference between ladle (cast) analysis and Product check analysis.

The material is the same as you pointed out, but can still have some slight variability. The instruments used to analyze can also have some slight calibration sensitivity, and response variation, and then add to it the variation of slightly different sampling and sample prep and operator variation and these variations can stack up, not just cancel each other out.

This presumes that you are using the right instruments for the job. If on topp of that you are analyzing for carbon using spectrometer instead of Leco combustion, then that is a new source of potential error as well.

Milo 'Former Lab Supervisor'

Thanks Mr MILO