Videos - Master Smith Don Fogg demonstrates and discusses Heat Treatment
Master Smith Don Fogg demonstrates and discusses Heat Treatment in these two YouTube video clips filmed at the New England School of Metalwork in Auburn, Maine. Also participating are NESM Director Dereck Glaser and Master Smith Jim Crowell.
[media] http://www.youtube.c...h?v=4Eh7nEhvxt4 [/media]
[media] http://www.youtube.c...h?v=pIrpv1lIDug [/media]
Dan Cassidy
Journeyman Smith
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Cool stuff from a master. Definitely food for thought. Thanks Dan.
Brion
Brion Tomberlin
Anvil Top Custom Knives
ABS Mastersmith
Thanks for posting this Dan.
It's always like christmas when Don stops by!
This left me a bit confused. It is my understanding that austenite cannot form below 1333 F (A1). It was also my understanding that at that temperature A1, a simple carbon steel of .84 C with no alloys (not manganese or anything other carbon) would, given a reasonable amount of time (10 to 15 minutes), transform into austenite. This is the laboratory, everything is perfect, euctectoid temperature for transformation. Now in the real world most steels have alloys (e.g., manganese, sulfur, chromium, vanadium, etc.) at sufficient levels to raise the euctectoid level so that we have an A3 temperature that designates the temperature where there is full conversion to austenite. Additionally, a steel that has less than .84 C or more than .84 C will require additional temperature for full austenite conversion. Temperature in everything that I read is the principle factor in determining what percentage of the base structure is transformed into austenite.
This video made me wonder if I am missing something. There was this implication (not a direct statement) that you could get full or almost full transformation to austenite at a lower temperature if you held the steel at a lower temperature long enough. The implication is that it is one of time as well as temperature in the transformation to austenite. This made me go back and try to find some article that would verify or refute that implication. I was unsuccessful by the way only finding articles that describe temperature as the independent variable in relation to austenite as the dependent variable.
So here is the question. If I took 1095 steel and held it at 1333 F long enough would it undergo complete transformation to austenite or is it really a function of temperature and I need to heat the steel to 1450/1475? In other words it is a function of temperature and if I want a higher percentage of austenite to form, I must increase the heat up to the A3. (BTW the smaller the percentage of austenite that forms the smaller the resulting percentage of martensite that can be formed).
Dan Petersen
