[philonossis]

how can the composition of metals be tested?

Is there a standard format, e.g.,
first apply one chemical that reacts with steel,
then one that reacts with magnesium,
then one that reacts with zinc...?

If a reaction is noted it means the metal has some amount of that reacted metal in it?



 

[Borek]

Each metal/alloy has its own set of procedures known to work best. First step it to dissolve the sample. How - already depends on the composition.

[Enthalpy]

More methods exist outside the chemistry lab. One device creates sparks with the alloy and analyses the spectrum, for instance.

Depending on your need, you'll have worries with some elements: carbon, silicon, boron, nitrogen - these two being intentional and very active in 0.1% concentration -, phosphorous... which are absolutely necessary to measure in most steels.

Normally, density (which is easily measured to 10^-3 accuracy on a simple shape) gives you the main element and the main alloying element including its proportion, a very good start.

[philonossis]

Depending on your need, you'll have worries with some elements: carbon, silicon, boron, nitrogen - these two being intentional and very active in 0.1% concentration -, phosphorous... which are absolutely necessary to measure in most steels.

thanks for responding, but I have a little trouble understanding your answer.

by "worries" do you mean they are difficult to measure: carbon, silicon, boron, and nitrogen?

"these two" means nitrogen and phosphorous?

by intentional do you mean they are placed in the alloy to cause worries? or that they are intentionally included while they other metals are not ?

[Enthalpy]

My contribution wasn't clear, yes...

Most analysis methods are unable of measuring some of the elements present in the alloy. Dissolving in a acid won't show the nitrogen contents, probably not the phosphorus nor silicon, and so on. Sparks-and-spectrum don't show properly light elements.

Some elements are desired in some steel, even in small amounts, like nitrogen in Duplex 2205 or boron in some turbine refractory steel.
Other elements are very detrimental, hence not intentional, and must be measured. Phosphorus embrittles steel even in small amounts.
Some alloys specify a very low guaranteed maximum of some elements, like 0.02% carbon in many stainless steels.

Well, other alloys are less varied and exotic than steel, which should provide you the most headaches. Don't lose heart!

[philonossis]

My contribution wasn't clear, yes...

Most analysis methods are unable of measuring . Don't lose heart!

thanks for this clarification.