Recently, I have read a book "Metallurgy fundamentals" by Daniel A Brandt. It is written in the style of a 7th grade physical science book - definitely an introductory text. I am glad to learn about the various crystals: ferrite, pearlite, cementite, the molten austenite, and the hardened form - martensite. I have not run across "Isothermal Transformation Diagrams" more than maybe once before, and I'm not sure why I don't see alot of them in blacksmithing books. I would guess that most blacksmiths use the metal color and personal judgement as their guide.
I am still working at the craft, but until I have a more respectable update, here are some links.
Google Books - Blacksmith has some older books with full text. I believe they will be allowing PDF download soon.
Steel Working and Tool Dressing: A Manual of Practical Information for Blacksmiths and All Other Workers in Steel and Iron
The Modern Practice of American Machinists & Engineers: Including the Construction, Application,...
George Dixon - creator of Artist-Blacksmith Magazine
http://artist-blacksmith.blogspot.com
Yet Another Railroad Track Anvil Project
http://www.castle-ranch.com/crafts/Anvil/anvil.htm
(has a recipe for cutting oil)
From The Blacksmith's Corner
http://blacksmithscorner.blogspot.com/
Free PDF Craft Books - some of these are EXCELLENT!
http://www.countryside.gov.uk/NewEnterprise/Economies/craftpublications.asp
Mechanical Engineer's Handbook, 1916 edition
http://chla.library.cornell.edu
Good Books from Amazon
edit: removed a dead link.
