How does 303 Stainless Become Magnetic? 5

[Strider17]

It is well known that 300 Series Stainless can
become magnetic by cold working. What is the
mechanism? How can a macro type operation
affect what is a nuclear property? I can't find
this in any of my metallurgy books...Thanks

 

[TVP]

Briefly, the austenite in austenitic stainless steels is metastable, meaning that it will decompose into martensite if given a suitably energetic input. This input is usually in the form of cold work (strain imposed at a temperature below the recystallization temperature). You should be able to find a more comprehensive description of this either on this site (use the search function) or from a reference book like ASM Handbook Volume 1 or Volume 9.

 

[EdStainless]

The maternsite forms is a result of strain or local chemistry variations. Often this only happens when the material is cooled below room temp. In fact you can make SS very magnetic if you deform it at low temperatures.

The magnetism isn't an atomic level property (well, it is , but in the sense that Fe and Ni are magnetic). The structure and order of the atoms into crystal structures are what result in the net apperent magnetic properties for an alloy.
I am sure that there are newer bookd on the subject, but if you can find a copy or "Ferromagnetism" by Bozorth you will have a good basis.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[mcguire]

There is an excellent book titled "Alloying" editted by John Walt which explains why austenite transforms to the less dense martensite due to the repulsion between the unpaired 3d electrons of neighboring atoms. The unpaired 3d electrons are the underlying cause of the ferromagnetism.

 

[hacksaw]

curious as to why you believe that the magnetic properties are nuclear?