Kiln 1084 heat treating questions

D

Dmitry5

Joined
Nov 6, 2017
Messages
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Sorry about there simple minded nature of my questions :)

1. Do I place the steel into the cold kiln and let it heat up to temp or place the blades into a preheated kiln?
2. How long of a "soak" to assume metal is at kiln temperature? I have read 15 min, is that roughly accurate?

Thanks,
Dmitry
 
1084 is easy, you don't need a soak at temp.

Heat your oven up to your quench temp, put the blade in and wait till the temp comes back up. Wait a minute or two then quench.

A quick glance in will let you know if your blade is at temp. The blade should be the same color as the rest of the oven.
 
Thanks for your reply.

So put it into a hot oven? Would starting with cold oven and heating to temp make a difference?
Estimated time for blade to heat up when placed into a 1425F over? 5 min? More less?
 
It can make a difference, as the oven heats up the heating coils will be much hotter than your final temp. This can make your knife reach higher temps than you want, which can make your grain size larger which leads to a weaker knife.
Plus, it can also lead to uneven heating, which leads to warps.
Also, it can lead to more decarburization, which is a pain to deal with.
 
A.McPherson said:
It can make a difference, as the oven heats up the heating coils will be much hotter than your final temp. This can make your knife reach higher temps than you want, which can make your grain size larger which leads to a weaker knife.
Plus, it can also lead to uneven heating, which leads to warps.
Also, it can lead to more decarburization, which is a pain to deal with.
Click to expand...

I see. So preheat and put the knife in. How long should I expect it to take to "get to temp"? I thought the ovens were designed not to overshoot the set temp - In reality they still do?
 
They still do.

The temp sensor is not sensing the heat of the coil, it's sensing the heat of the air or the insulation depending on how its built.

Some are better than others, but most, if not all ovens really only have two states for thier heating coils. On and off. So the computer modulates how long the elements are on to reach the desired temp.

I don't know how long it will take your oven to get up to temp. Some take minutes, some take an hour.
 
A.McPherson said:
They still do.

The temp sensor is not sensing the heat of the coil, it's sensing the heat of the air or the insulation depending on how its built.

Some are better than others, but most, if not all ovens really only have two states for thier heating coils. On and off. So the computer modulates how long the elements are on to reach the desired temp.

I don't know how long it will take your oven to get up to temp. Some take minutes, some take an hour.
Click to expand...

Sorry, I meant how long would it take for the knife to go from 70 to 1450F in a preheated kiln? 1/8 10 inch blade.
 
After you put your blade in, wait for the temperature to go back up to the set point and wait an extra minute or so. Then, take a quick look inside and make sure the entire blade is the same color as the rest of the furnace. You will see if it is a uniform color and at the right temperature or not.

I guess a blade this size/thickness would take on the order of five minutes in my furnace, give or take a minute or two.
 
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