Annealed file remained hard...why?

[Steve Sells]

53 minutes ago, BeaverNZ said:

 Isnt all tempering regardless of the amount done at subcriticle temps?

read the pinned post on advanced annealing and you may understand the term self-critical anneal

 

 

[Joël Mercier]

https://en.wikipedia.org/wiki/Bainite

The way I understand it, to properly sphero anneal those steels, it must be soaked at a sub critical temperature for a few hours and be cooled very slowly. This will create mostly pearlite. 

Just bringing the steel to critical and letting it cool in vermiculite might be enough to create some amount of unwanted bainite. 

[BeaverNZ]

 Steve ,Im just an old plodder and possibly a bit obtuse LOL I have read your article on annealing which was interesting but wasnt it dealing with alloy steels when the subcriticle methods were used and the file steel in question just a plain carbon steel? I am interested to learn more thats why I spend more time here than I should at times Cheers Beaver

 

[BeaverNZ]

On 3/9/2018 at 12:14 PM, Steve Sells said:

didnt you read the post? he did anneal it... thats the problem

Hi Steve I have been thinking about this thread and have read the info you put up and just wish to understand better if i am incorrect. He said that he had annealed the said item and what I have read from some of the other posts along soak my of produced Bainite that was I suggested tempering which is as I understand a differnt process and done at different temps, Heat treatment is not my field of expertese and wish to understand more

[jlblohm]

One question i have is have you ever sharpened a drill bit before? I have watched a lot of people try to sharpen a drill bit and they end up with the same problem you are having. There is more to sharpening a drll bit than touching up the edge. 

[Smoggy]

Most folks don't even bother sharpening drill bits as Jobbers are so cheap to buy, blunt or break and discard. Not only do they not know how to sharpen a bit they are unaware that optimal geometry differs for each metal, when you purchase a drill it is sharpened for general use and as such it isn't strictly correct for any metal. Those that you have watched sharpen drill bits may well have achieved a well sharpened bit, and then drilled too fast with too little pressure.

"Speed and Feed" as mentioned above, most "hobby use" drill presses will not gear down low enough (that's why many fit a set of reduction pulleys).

Those who still use the old handcranked drill presses will be able to testify to their ability to drill through just about anything (eventually) and not be forever resharpening bits.

(As also stated above, WD40 is not a suitable lube for machining steels but it is good for alluminium alloys.)

[Steve Sells]

who said we have to spherodise the steels ?  just super high tempering, and  Iirc Bainite is not going to be produced by tempering, its is produced from the quench and being held at those temps, it is a different process, even tho at first is may appear the same.

[jlblohm]

On 2/2/2018 at 5:41 PM, arkie said:

The bit was newly sharpened, BTW

Arkie even mentioned it in his original post that the drill bit has been sharpened. I didnt just assume it was.