[TheForge] found an interesting tidbit on steel ID while looking for hydraulic line info

[Cameron Stoker]

Hi,
	I found an interesting tidbit in an FAA guide on aircraft plumbing.  
It may not be usefull for most of the alloys we fiddle with, but it's 
something else to add to your bag of tricks.

Before I post this little table, I was wondering if anyone has experience 
doing 'hard' (i.e. steel tube) hydraulic lines. Where do you get your pipe/
fittings?
I am looking to replace some rubber/steelwire hoses with something more 
compact.



http://www.faa.gov/avr/sups/chapter5.pdf

It may be necessary to test samples of the material for
hardness by filing or scratching with a scriber. The magnet test
is the simplest method for distinguishing between the annealed
austenitic and the ferritic stainless steels. The austenitic
types are nonmagnetic unless heavily cold worked, whereas the
straight chromium carbon and low alloy steels are strongly
magnetic.
Figure below gives the methods for identifying five
common metallic materials by using the magnet and concentrated
nitric acid tests.
Magnet 			Nitric 			acid
Material 			test	 			test
-----------------------------------------------------------------------------------
Carbon steel 		Strongly 			Slow chemical
				magnetic. 		action, brown.
18-8 			Nonmagnetic. 	No action.
Pure nickel 		Strongly 			Slow action,
				magnetic. 		pale green.
Monel 			Slightly 			Rapid action,
				magnetic. 		greenish blue.
Nickel steel 		Nonmagnetic. 	Rapid action,
								greenish blue.


I'm not too familiar with 'nickel steel' or 18-8, but I bet this is more 
accurate than a spark test.



                                      Cameron Stoker
                                      cameron@stokerforge.com
                                      http://www.stokerforge.com