Heat treat question.

Tod Lowe

Tod Lowe

Well-Known Member
Im using 1080 steel.
I used the rockwell tester here at work and it reads im getting a hardness right at 56 hrc.
My process has been to temper for 2 hours at 400 degrees after the quench.
If I want to get a higher rockwell do I just cut back on the time in the temper oven? Our rockwell machine only goes up to 63 hrc so I couldnt check right out of the quench.

The 1095 steel I used checked at 58 rockwell and I only tempered it for 1.5 hours so im thinking I need to just cut back my temper time on the 1080?
 
Shankmaker said:
Im using 1080 steel.
I used the rockwell tester here at work and it reads im getting a hardness right at 56 hrc.
My process has been to temper for 2 hours at 400 degrees after the quench.
If I want to get a higher rockwell do I just cut back on the time in the temper oven? Our rockwell machine only goes up to 63 hrc so I couldnt check right out of the quench.

The 1095 steel I used checked at 58 rockwell and I only tempered it for 1.5 hours so im thinking I need to just cut back my temper time on the 1080?
Click to expand...

What temperature did you temper the 1095 at? time doesn't really make any difference whether 1.5 hours or 10 hours it should be within 1 point.

Fully hardened 1095 requires over 500F temper to get down to 58 RC so maybe there's something up with the hardening process itself.

What temperature are you quenching at and what is the quenchant and temp of quenchant?
 
Steve_G said:
What temperature did you temper the 1095 at? time doesn't really make any difference whether 1.5 hours or 10 hours it should be within 1 point.

Fully hardened 1095 requires over 500F temper to get down to 58 RC so maybe there's something up with the hardening process itself.

What temperature are you quenching at and what is the quenchant and temp of quenchant?
Click to expand...

I tempered the 1095 at 450 for 1.5 hours. I dont know the temp at quench. All I can tell you is I took it to nonmagnetic and soaked it a few more minutes then quenched it in 100 degree Vegetable oil.Then I wipe it down and it goes straight to the oven. Pretty crude but thats what I have at the moment.
I made the fillet knife out of 1095 because thats all I could find in the size steel I wanted. I cleaned 16 bass with it the other day and it would still shave hair off my arm. Thats better then the Rapala knife I have will do.
 
I just re-read your first post and another major variable is tempering temperature control. How is the temperature being controlled?

If you are just popping the blades in the oven and setting the dial to 400, that is probably the problem. I did some testing with a muffle in the oven and took temp readings from inside and outside while the oven cycled on and off through two complete heat cycles. The oven temp fluctuated over 100 degrees while inside the muffle only about 8-10 degrees.

here's a link to the thread I posted about the muffle.

in the pictures, it's kind of hard to make out the bottom cookie sheet is a double layered air insulated sheet, this is crucial to the function. One can be improvised by a regular cookie sheet with a couple small cooling racks placed inside and then covering with aluminum foil.
 
Thanks for the great info Steve.
I actually use a toaster oven. I have a thermostat placed in there. It really maintaines the temp verry good.It is about 20 degrees off from what the dial reads but it does not go up and down in temp. Once there it seems to stay.
This muffle is something I may look into though if problems come up.
 
Shankmaker said:
Thanks for the great info Steve.
I actually use a toaster oven. I have a thermostat placed in there. It really maintaines the temp verry good.It is about 20 degrees off from what the dial reads but it does not go up and down in temp. Once there it seems to stay.
This muffle is something I may look into though if problems come up.
Click to expand...

On that note You can get a fire brick to do pretty much the same thing. It will hold in the heat and keep a more constant temp. and for the lower temps(250-400degrees) I use a toaster as well with the brick.
 
If your Rockwell hardness is not approximately what it is supposed to be at a given tempering temperature, simply adjusting that temper temp to get the RC value you're looking for may not address the fundamental problem. If the hardness is not in the expected range, that may indicate that you did not get full martensite conversion. The presence of pearlite (or retained austenite in complex steels for that matter) will reduce the edge stability of a blade at any given measured Rockwell hardness.

If an unexpectedly low RC number indicates that something may be off about the HT, and you're confident about your soak and your temper temp, I might be suspicious about your quench medium. Warm vegetable oil does not quench very quickly. Perhaps you're not getting under the nose. Warm mineral oil is a faster quench if you don't want to spring for HT oil. If you're going to use vegetable oil, they say canola is the fastest.
 
Nathan The Machinist said:
If your Rockwell hardness is not approximately what it is supposed to be at a given tempering temperature, simply adjusting that temper temp to get the RC value you're looking for may not address the fundamental problem. If the hardness is not in the expected range, that may indicate that you did not get full martensite conversion. The presence of pearlite (or retained austenite in complex steels for that matter) will reduce the edge stability of a blade at any given measured Rockwell hardness.

If an unexpectedly low RC number indicates that something may be off about the HT, and you're confident about your soak and your temper temp, I might be suspicious about your quench medium. Warm vegetable oil does not quench very quickly. Perhaps you're not getting under the nose. Warm mineral oil is a faster quench if you don't want to spring for HT oil. If you're going to use vegetable oil, they say canola is the fastest.
Click to expand...

There are many things that could be going wrong in my method that I cant verify but I can control the quench oil. I will try the mineral oil if it is better. I heard the heat treat oil was in such high demand the price has got rediculous.
I will do a search for it.
Thanks and thanks rusty for the brick idea.
 
Vet supply houses have it cheap in bulk, I think it is used as a stool softener for livestock.

I believe that HT oil is 99%+ mineral oil with additives to reduce oxidation and fire and control the vapor jacket. You'll want to be sure to agitate very well to get an even quench with a poor man's oil.
 
Nathan The Machinist said:
Vet supply houses have it cheap in bulk, I think it is used as a stool softener for livestock.

I believe that HT oil is 99%+ mineral oil with additives to reduce oxidation and fire and control the vapor jacket. You'll want to be sure to agitate very well to get an even quench with a poor man's oil.
Click to expand...


Most farm stores have it by the gallon and quart. They use it for Colic in horses I have to keep the stuff.
 
I had to come back and read this post. I'm so stupid I was in walmarts bake goods isle looking for mineral oil. I guess I need to look at rural king.
Thanks.
 
Shankmaker said:
What temp do I heat the mineral oil before quench?
Click to expand...

Houghton Quench K recommends 140 degrees F and is their fast quench oil that is mineral based. You should probably try 130 degrees F as you are using straight mineral oil.

Stay clear of the smoke now that your not using cooking oil ;)

Mike
 
Gotta agree with Nathan. That vegi oil isn't fast enough for 1095. 1095 works best for me in a brine or Parks #50 quench. I'd recomend parks #50( I have cracked a few blades in the brine ).
 
Oh the dreaded "TINK" and your done! Start over! do not pass go do not collect $200.
I hate it when that happens. But it has only happened to me twice once with 1090 and once with W2. and both times with Brine! I poured that stuff out as quick as I could.
 
jawilliams0425 said:
Rusty are you hollowing out the brick or building a box?
Click to expand...

Just leave it whole so it will hold as much heat as it can. Think of it as a hot water bottle for your toaster. when it gets hot and holds in that heat the oven has made, it will let it out slow and keep the oven at a more stable temp. I just set the blade on top of it edge up and let it soak.

My wife wants me to get one of those oven slabs now from pampered chef, you know the ones that they cook pizza's on. same principle.


Oh and you can get mineral oil at a vet/farm supply store by the gallon or at the pharmacy for like .89 a pint bottle, It is also good for putting on wood, bone, leather just try not to drink it it's also a cure for constipation!:haha:
 
I tried the mineral oil tonight.
The stuff I got from TSC is called mineral oil light.Its all they had.
I did the normal procedure and quenched in the mineral oil. Tempered at 350 for 2 hours.
I tested Rockwell at work tonight and got average of 56.
I still don't think its getting quenched fast enough.
What exactly are we looking for in a quench oil? We use a synthetic oil here at work that I thought about trying.Its used to keep work rolls cool and lubricated on a Cold mill.
 
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