failed annealing attempt (of O1 and K100 aka D3)

SHOKR

Well-Known Member
hey guys

long story short sometimes when i drill holes they harden when i cool with oil, so far i had no means of annealing but i bought an HT oven so few days ago i tried annealing O1 and k100 together

set to 1460F for an hour and let them cool inside the oven overnight

i already had all the holes established with smaller bit (5mm), one the O1 blade i had very thin bit of steel remaining from the larger (8mm) bit, and on the k100 most of the steel was intact, anyway after annealing the drill bit still didn't go through and kept squeaking (tried several bits)

any ideas?
 

GHEzell

Well-Known Member
Heat to 1325f for an hour (just under non-magnetic), let cool overnight. This will basically, in non-metallurgical speak, temper the heck out of them (sometimes called a sub-critical anneal). They will not be as soft as a full textbook anneal, but they will be soft enough to drill and file. You will need to re-harden the blades afterwards.

Or just use a carbide drill bit.
 

SHOKR

Well-Known Member
thanks George

I am thinking about the carbide bit, but at this point I actually want to learn to anneal

but isn't 1460 still non magnetic? whats the difference between it and 1325?

thanks
 

GHEzell

Well-Known Member
The curie point, or critical temp for steel is 1414f, this is the point where steel will loose its magnetism (different sources actually give different temperatures, ranging from 1360f to 1414f). To do a sub-critical anneal you want to stay under this temperature, you do not want the steel to become non-magnetic. You do not want the steel to become austenite, this is why we call it a sub-critical anneal...:) Think of it as an extremely high tempering cycle.

Annealing instructions for D3: "Annealing should be performed in a controlled atmosphere furnace. Heat thoroughly to 1600 F and cool slowly, at a rate of not more than 20 F per hour, until furnace is black. Material may then be removed and air cooled." (see also http://fordtoolsteels.com/wp-content/themes/twentytwelve/pdf/LSS_D3.pdf, which gives more detailed instructions)

Annealing instructions for O1: "Heat to 1400 to 1450 °F (760 to 790 °C). Use lower temperature for small sections and higher tem@perature for large sections. Cool at a maximum rate of 40 °F (22 °C) per hour. The maximum rate is not critical after cooling to below 1000 °F (540 °C)." This is from Cashen's website...
 

SHOKR

Well-Known Member
ahh got it!
at first you're talking about the O1 right?
from the data sheet of the manufacturer of K100, they say 800C to 850C (1470F to 1560F) which is somewhat close to the data you provided

the temps for both steels were so close i thought I would do them both in one go, but well, neither worked...

thanks George for the info
 
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