1095 Heat Treat NightMare !!*Update*

Battle Creek Knives

Battle Creek Knives

Joined
Feb 23, 2010
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Okay I posted my original "fail" in a heat treat forum, and was told there to redo my original fail..

so I retreated the blades and still am only getting 48-50RC...

The first time I treated the blades I did 6, 3 were 1095, 2 1084, 1 01.. after I had them tested they all failed but the 01 blade 58-60... since this was the first time I've ever done 6 blades, I realized on the last quench I let the oil rise to 150*:eek: so this time around I kept the oil at 130* perfectly but still failed..

I let it soak at 1500 for 10 mins, 425 2x2 ..

I've had good results with 5160, 01 in canola oil... But I'm assuming I need a faster oil..

That's the only thing I can see I'm doing wrong as 1084, 95 require faster quench times...

this is a huge delima as I finally have a handful of designs I've settled on and would like to start selling to the general public to start recouping some of my major start-up costs before my wife kills me :D

ETA: this is Aldo's 1095....
 
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What are you testing with? If your time And temperature are correct, then I'd say one thing is the MOST likely. DeCarb. I suspect you are not removing enough steel after heat treat to get below the decarb layer.
:-)
 
so you're saying before I have it tested to grind it down at the handle?? loose the decarb?

the shop I have do it does it free with an actual rockwell press, so he wouldn't likely tell me that.... as it may cost me :)
 
You need only clean-up a dime sized area on the tang for testing( assuming you are also quenching the tang) are you testing after the quench ? Or after the tempering cycles? What is your tempering source?
 
Cut you two coupons of each steel,H/T them both,on two leave them as quenched and temper two of them,grind them to a 400 grit finish and have them all tested,That should tell you where your problem is.
Stan
 
JBS TOOLMAKER said:
You need only clean-up a dime sized area on the tang for testing( assuming you are also quenching the tang) are you testing after the quench ? Or after the tempering cycles? What is your tempering source?
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I've tested after quench with the skate method, and really I'm at a learning curve as I think I can even tell more now by sound? if that makes sense... and it appears to pass that well... but I have no intention of selling any knives without an rc test so I take them in and find out the bad news... and after double HT these probably have a touch more decarb then the first time....

for blades larger then 15"oal I use a convection oven in my house, smaller blades I have a tempering oven that I tested to hold steady temp... besides if it was a tempering problem shouldn't I have higher readings??
 
I like Stan's idea, test one quenched and ground, test one quenched tempered and ground. Yeah your tempering oven would be way off to get you down to 58-60, I didn't read that the first time.
When you say skate method I have a sharp pain in the center of my canine teeth. Have you had the file Rockwell tested? The file could be 54 and "skate" across a 56.
Not trying to be a smartass, just trying to prevent some bad habits. I know a lot of makers use this method but that doesn't make it a good one.
 
SBuzek said:
Cut you two coupons of each steel,H/T them both,on two leave them as quenched and temper two of them,grind them to a 400 grit finish and have them all tested,That should tell you where your problem is.
Stan
Click to expand...

good idea.. 400 grit !!!!:eek: okay I'll do it.. the rockwell guy also wanted me also to bring in steel for testing before HT..

JBS TOOLMAKER said:
When you say skate method I have a sharp pain in the center of my canine teeth. Have you had the file Rockwell tested? The file could be 54 and "skate" across a 56.
Not trying to be a smartass, just trying to prevent some bad habits. I know a lot of makers use this method but that doesn't make it a good one.
Click to expand...

good point and to be honest the one I test with is the first one I've broke simply by dropping it on the ground the other day, snapped it in half... it is a nicholson...
 
Skate test is semi worthless. Several months ago we wasted 2 weeks talking someone through this exact scenario with 1084, he refused to accept that he had heavy decarb so we took him through calibration of his kiln, thermocouples, etc. And I finally convinced him to grind down 2 thousandths and test, then another 2 thousandths and suddenly he was getting good numbers. At .006 if I remember he was safely through his decarb into good metal.

More later when I am not pinky typing on a phone

-Page
 
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^^^
Yes, yes and yes to what page has to say.

I have to ask why you are HT'g such different steels at the same time? 1084 is different from 1095, which are both different than O1. What is your heat source for HT'g. If it is a kiln are you letting it pre-heat prior to putting your blades in? Same with your tempering ovens. I recently made a thread on temperature spiking. Conventional ovens are horrible for overshooting the mark by hundreds of degrees in some cases.
 
The file skate test tells you very little, files will skate on scale, a slightly used file will skate on pearlite, a file that has skated on full hard steel will be dulled so it will not bite the same way the next time (I could go on)

Let's back up to the point of beginning
what are you using for a kiln?

were you tempering with the fan on or off in your convection oven? or were you tempering in the other oven?

Most importantly, have you tested an area with .0040 removed after HT?

Start with brand new steel and make test coupons, preheat your kiln and let it equilibrate for a half hour before you start, put your coupons in, it will take them 5-10 minutes to come up to temp, soak them at temperature for 20 minutes after that and quench them allowing no more than a second from leaving the kiln to full immersion in the oil

grind them gently to at least 4 thousandths dipping in water with a teaspoon of dish soap in it every ten seconds and using fresh sharp belts to avoid heating the sample area

test them

Grind another 4 thousandths, see if you get the same result, if you do you are below the decarb, if not grind and test again until you have 2 consecutive results reading about the same

temper them

test them again (you shouldn't need to regrind them after tempering)

My guess is that you are experiencing decarb, this test will allow you to test each part of your process

-Page
 
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Page,
I have noticed your thickness recommendations on decarb removal. Have you inadvertently moved the decimal one digit to the right?

Working from 1/8" stock ( .125"), if you remove .060" from each side, you have no blade left. removing .040" would leave the blade about as thick as an Exacto blade.
Perhaps you meant to recommend removal of 4-6 thousandths (.004-.006), not 40-60 thousandths.
 
Good catch Stacy. My micrometers are verneired to tenths of a thousandth, I always start with the vernier and work backwards. It all makes sense in the shop, but doesn't always translate to typing. To compound the error, I am used to looking at decarb through the microscope and measuring it in microns. Thank you! I hope that my notation error has not caused anyone problems

-Page
 
DAMMIT.... I just ground a 1/8" off of a 3/32" blade!!!

the-imploded-house-texas-2.jpg
 
sunshadow said:
Good catch Stacy. My micrometers are verneired to tenths of a thousandth, I always start with the vernier and work backwards. It all makes sense in the shop, but doesn't always translate to typing.
Click to expand...

That is funny... I did the same thing as an engineer/machine operator for the Tool/Die/Mold industry and didn't think twice about your numbers.
 
okay here's what I've come up with so far..

yesterday I took in a blank knife and one that I ground down a progression of belts to 280, decarb by the naked eye was removed...

We got the same results, he wanted to play with both pieces so I left them there... untreated blank measured 10-12

now on to your questions...

I have a SC24" knife making kiln.

I did not bring to temp before inserting blades, I mistakenly put in the 1084, to be honest I'm only assuming those 2 pieces were 1084 I'm not 100%, they may very well be 95.. its been on the bench a while......

the 01 I put in there strictly as a test, this is a bench knife..

Rick I seen your thread about the templestics, I need to do that.. matter of fact I think everyone should... I've looked around the net and have yet to find a kit with multiple degrees and most are just sold in a pack of 10, they look like crayons and I'd assume 10 would last a life time?? did you buy yours in a kit??

I'd hate to think my kiln is that far off.. with that said my steel is only hardening to 42 now so its 30 points harder then stock.. :(

I will try 2 different coupons and see what happens, because the rc tester is around 12miles away I think I will leave one just quenched and ground but will temper the other before bringing them both in....to save multiple trips
 
Battle Creek Knives said:
okay here's what I've come up with so far..

yesterday I took in a blank knife and one that I ground down a progression of belts to 280, decarb by the naked eye was removed...

We got the same results, he wanted to play with both pieces so I left them there... untreated blank measured 10-12

now on to your questions...

I have a SC24" knife making kiln.

I did not bring to temp before inserting blades, I mistakenly put in the 1084, to be honest I'm only assuming those 2 pieces were 1084 I'm not 100%, they may very well be 95.. its been on the bench a while......

the 01 I put in there strictly as a test, this is a bench knife..

Rick I seen your thread about the templestics, I need to do that.. matter of fact I think everyone should... I've looked around the net and have yet to find a kit with multiple degrees and most are just sold in a pack of 10, they look like crayons and I'd assume 10 would last a life time?? did you buy yours in a kit??

I'd hate to think my kiln is that far off.. with that said my steel is only hardening to 42 now so its 30 points harder then stock.. :(

I will try 2 different coupons and see what happens, because the rc tester is around 12miles away I think I will leave one just quenched and ground but will temper the other before bringing them both in....to save multiple trips
Click to expand...

How are you seeing decarb with the naked eye? are you sure you are not mistaking scale for decarb?

try bringing your kiln up to temp and letting it stabilize there for 20 minutes after it indicates that it has reached temp, bring your oil up to temp by whatever means you normally do. Put your test coupons in the kiln sitting vertically in a fixture that does not allow them to touch the floor of the kiln, just as you would a knife blade (I made my fixture out of 1/8 inch stainless steel wire, I have seen lots of problems over the years from people putting their blades in kilns lying flat on their side on the kiln floor) and allow 10 minutes for them to come up to temperature, and another 10 minutes for soak time then quench, then try grinding 5 thousandths off one side after you have removed the visable scale and 10 thousandths off the other, that should get you below your decarb, then test them. let us know what you get

-Page
 
Here is a good source for Tempilstiks. I bought mine here in Canada. One, in each of your chosen temperatures will last a loooooong time....... unless you develope a taste for them... the red ones are particularily yummy!

I bought mine individually, in 50deg increments from 1200F to 1800F. I believe they go up to 2100F, maybe higher... check it out.
 
sunshadow said:
How are you seeing decarb with the naked eye? are you sure you are not mistaking scale for decarb?
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Assuming the decarb is the blotchy looking steel, that is what I removed down to fine grain steel..

for the moment I just slotted a firebrick to hold my knifes tip up.... Thanks for the stainless steel idea, after all the expenses for my shop over the last 6 months or so I really don't want to up another $20 for a stand if I don't have to... :)

I'm leaving out of town for a couple days tomorrow so I doubt I can get my blanks tested but I will treat them today regardless...
 
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