Aim weight % vs Acceptable weight %

[hsemus]

Hi,

Could you please describe me whats the difference between an AIM WEIGHT % vs ACCEPTABLE WEIGHT % in a chemical composition chart for a material specification.

i also got some values for acceptable weight is much higher than aim weight.

Regards
sume

 

[cloa]

I can't say for certain.
But for me it sounds like
Aim is like normal- the percentage of element that allows achieving the desired properties easily at low cost.
Acceptable is maximum percentage- normally only occurring due to scrap or slight process variation (added too much or the raw powder has some variation element content) or perhaps a cheap source of the element.
Should some minimum depending on the element- metalloids like sulfur for ordinary carbon steels would have no minimum but manganese would have a minimum.
The actual percentage needed depends on achieving the properties depending on the processing specified.

For instance low alloy steels might allow up to 1% Nickel acceptable but aim for 0.1% Nickel

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[jwhit]

The aim composition as stated by cloa is an optimized composition, usually generated by the manufacturers material engineers. Since melting and casting of materials, or blending of raw materials isn't always an exact science there has to be some leeway from optimum to acceptable. Hence, composition ranges. In a foundry situation, for example, there are literally hundreds of things that can influence the final results for a heat of steel. In a perfect world what went in to the pot comes out all blended nicely together, this isn't a perfect world.

 

[consultmet]

If I understand your question correctly,

The acceptable % range is provided in a material's chemical specification to provide the limits for which the intended chemical analysis will met the reguired mechanical properties and acts as a acceptance or in spec./ out of spec determination of the element.

The aim % is sometime given as the most optimum single Wt.% value to aim for to meet the properties.

Hope this helps

 

[dbooker630]

In some specifications the aim value or range is to be met most of the time, for example at our company 90% is a target used frequently in material specs.