Need Help Troubleshooting Results

It will be interesting to see results once you get a chance to try an 1/8" coupon heated to a higher temp. Bet that solves the problem. Perhaps heat one 1/4" coupon and draw it out to 1/8" for testing?
 
I tested the second W2 knife that I did HT on over the weekend...spot on with the first blade at 64Rc post temper.
 
Ok, so here is a 26C3 blade that I hardened this morning. Based on a couple of previous 26C3 blades, I ran this through a normalization process (I found slightly better grain structure doing this vs. no normalizing) similar to 52100 at 1650f 20 min air cool, 1550f, 1500f, 1450f at 10 min and air cool. I clayed with Rutland's and austenized at 1475f for 13 min and quenched in Parks 50 for approx 8-9 seconds and then water (similar to what I do for W2 with good results). Quench was good, a light warp at the spine 2/3rd's way to tip...not bad at all and the blade was still a little warm and I put it in a vise....all good....then about 3 minutes later, I heard the first of 3 pops. I have not cleaned up or sanded the blade at all, but 3 quick tests gave me 67-68Rc, what I would expect. Anyway, a day in the life of a knife maker....this was the first 26C3 blade to crack on me....if I had it to do over, I would not have put it in water or the vise.

M9xN8oC.jpg


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DAMNENG said:
Just a thought.
I noticed no one has mentioned the procedure used to remove the steel from the oven and get it into the quench tank. Since 1095 has less than a second to clear the P nose, anything ,ess than immediate transfer will produce less than desirable results.
Jim A.
Click to expand...
It’s good practice to have the quench tank next to the kiln, no doubt. I watch guys on FiF on the final round at their home shops with quench tanks completely across the shop. Like....huh?

But, also I think some may be confused about how fast you need to get the blade into the oil. As long as the blade hasn’t cooled down to (or past) recalescence during transfer, everything is still in solution. 1095 and W2 have pearlite noses somewhere around 1/2 a second, and it’s impossible to remove a blade and have it quenched in a half second. So it’s not about the pearlite nose (that’s the oils job). It’s up to the maker to just be safe, smart, and practical about the oven-to-oil transfer.
 
Carterwhopkins Carterwhopkins - Carter, just curious here, but why would you want to quench in oil first and then quench in water afterwards? I'm aware of quenching in water first for a few seconds in order to get below the nose faster than most oils will, and then going into the oil after to let the steel finish cooling more slowly down to and below martensite finish in order to avoid the risk of cracking and maybe increased warping, but what would quenching in oil first and then into water achieve? Thanks


~Paul
My Youtube Channel
... (Just some older videos of some knives I've made in the past)
 
coldsteelburns said:
Carterwhopkins Carterwhopkins - Carter, just curious here, but why would you want to quench in oil first and then quench in water afterwards? I'm aware of quenching in water first for a few seconds in order to get below the nose faster than most oils will, and then going into the oil after to let the steel finish cooling more slowly down to and below martensite finish in order to avoid the risk of cracking and maybe increased warping, but what would quenching in oil first and then into water achieve? Thanks


~Paul
My Youtube Channel
... (Just some older videos of some knives I've made in the past)
Click to expand...
Yes, I know it is backwards to conventional interrupted quenching....I was playing around with W2 about a year ago, and that method gave me a slightly harder blade (like 1 point harder) and better hamon activity over just regular Parks 50 quench. I don't always do it, but did on a couple of W2 blades last weekend and came out of the quench at 68Rc and 64Rc post temper.

I'm going to try and duplicate this in the next few days with 26C3 and won't do the water bath....this was the first failure with 26C3.
 
Unfortunately, I have a new board for my RM3 controller on the way. Should be here Monday. After running my tests again I'll post the results.

Just out of curiosity, If I replaced the whole controller with a PID would it be as reliable or more reliable than the Evenheat controller? Could it be programmed for multiple segment profiles?
 
Carterwhopkins said:
Yes, I know it is backwards to conventional interrupted quenching....I was playing around with W2 about a year ago, and that method gave me a slightly harder blade (like 1 point harder) and better hamon activity over just regular Parks 50 quench. I don't always do it, but did on a couple of W2 blades last weekend and came out of the quench at 68Rc and 64Rc post temper.

I'm going to try and duplicate this in the next few days with 26C3 and won't do the water bath....this was the first failure with 26C3.
Click to expand...


That's really interesting. Any guesses as to why that increased hardness might happen? My metallurgical knowledge is still pretty limited, but I wonder why it might harden up more when quenched or cooled in water after being what I would guess is a decent amount below the nose after 8-9 seconds in the oil. Does faster cooling from Martensite start down to and/or below Martensite finish have any potential to increase its hardness? Don't get me wrong, I don't mean to sound like I'm disagreeing with you, I'm honestly just curious, as that order of quenching is completely new to me. Thanks

Btw, sorry for getting a bit off topic, Mark.

~Paul
My Youtube Channel
... (Just some older videos of some knives I've made in the past)
 
coldsteelburns said:
That's really interesting. Any guesses as to why that increased hardness might happen? My metallurgical knowledge is still pretty limited, but I wonder why it might harden up more when quenched or cooled in water after being what I would guess is a decent amount below the nose after 8-9 seconds in the oil. Does faster cooling from Martensite start down to and/or below Martensite finish have any potential to increase its hardness? Don't get me wrong, I don't mean to sound like I'm disagreeing with you, I'm honestly just curious, as that order of quenching is completely new to me. Thanks

Btw, sorry for getting a bit off topic, Mark.

~Paul
My Youtube Channel
... (Just some older videos of some knives I've made in the past)
Click to expand...
I don't have any intelligent answer....just a guy messing around and trying some different things...I have experienced it on a few different sessions, all with W2, and with pretty much the same results. It has worked for me, in my shop, with my equipment, it is repeatable and gives a good result for me and what I am looking for in a chef knife. Not sure why the 26C3 blew up...did I grind too thin, was it the water, was it the vise....next batch I will probably grind as thin and stop at the Parks 50 quench. I am not set up to temper immediately after quench...need to let the Evenheat cool for a while, but that has always been my case, so not sure that has anything to do with it.
 
Ok, got the new board installed. Ran the coupons through again at the same Aus temps but slightly less time at temp because the coupons keep getting thinner. Results below. Should I have completely annealed the coupons and re- normalized and cycled them before austenitizing again or was it ok to just re-harden?

ZmL4Dxe.jpg
 
i4Marc said:
Ok, got the new board installed. Ran the coupons through again at the same Aus temps but slightly less time at temp because the coupons keep getting thinner. Results below. Should I have completely annealed the coupons and re- normalized and cycled them before austenitizing again or was it ok to just re-harden?

ZmL4Dxe.jpg
Click to expand...
Did you try to quench in water one piece ?Maybe something with your P50 is wrong ?At the and this is W steel...water-hardening ?
1500 F would be what I will try next .. ..
PS. 1435F=779,4 Celsius , 1440F=782 Celsius .......difference is only 3 Celsius ?? Are you sure that your oven is capable for that ? I don t think ...
 
You might also try aus at 1475 and 1500 as well with a little longer soak time.
 
Ok, I just wanted to refresh this thread so it isn't left open ended. I'm sorry for the delay in posting but I've been busy. I thought it was important to bring this thread up to date because the topic about suspicion of steel quality and certain vendors comes up frequently. As most of us with a little experience know by now, many variables affect the outcome of our efforts. What is easily blamed on the steel can often be traced with a little effort to something else. Because the reputations of people and businesses can be unfairly tarnished it is important that we (should) strive to always be fair and thorough in our troubleshooting.

In my particular case, I was having a hard time getting my W2 to harden. The steel came from NJSB. After running a few sets of coupons with unsuccessful results I called the office and they put me in touch with Ed Braun who seems to be fielding their heat treat questions. Ed suggested I do a salt test. This involves making a series of small trays out of SS foil and filling them with table salt. Table salt melts at 1475˚f. Starting at 1475˚ on your oven readout, put in a new salt tray at 5˚ increments until the salt melts. Because the thermocouples in Evenheat ovens (at least the model I have) descend from the top of the oven chamber to about the middle of the chamber it takes it's most accurate reading from the middle to the top. The chamber can be 50˚ cooler at the bottom of the chamber where the knife sits. In my oven the salt melted at 1530˚f. So if I want 1475˚ in my oven where the blade sits I need the readout to show 1530˚. Also, because my tongs act as a heat sink when taking the small coupons out of the oven, I was instructed to drill a hole in the corner of the coupons and add a stainless wire handle with which to remove the samples. So I ran another set of coupons and the results were still lack luster. I called Ed back and he told me to add another 50˚. He also told me to skip the normalization and thermal cycles. I did and the results are below. At 1615˚ on my readout I am getting 67+ HRC. So if anyone is having trouble getting their steel to harden, make sure you examine all the steps of your process and the calibration of your oven before declaring that the steel is crap.

Here are my updated results:
gB1q1nk.jpg
 
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i4Marc said:
Ok, I just wanted to refresh this thread so it isn't left open ended. I'm sorry for the delay in posting but I've been busy. I thought it was important to bring this thread up to date because the topic about suspicion of steel quality and certain vendors comes up frequently. As most of us with a little experience know by now, many variables affect the outcome of our efforts. What is easily blamed on the steel can often be traced with a little effort to something else. Because the reputations of people and businesses can be unfairly tarnished it is important that we (should) strive to always be fair and thorough in our troubleshooting.

In my particular case, I was having a hard time getting my W2 to harden. The steel came from NJSB. After running a few sets of coupons with unsuccessful results I called the office and they put me in touch with Ed Braun who seems to be fielding their heat treat questions. Ed suggested I do a salt test. This involves making a series of small trays out of SS foil and filling them with table salt. Table salt melts at 1475˚f. Starting at 1475˚ on your oven readout, put in a new salt tray at 5˚ increments until the salt melts. Because the thermocouples in Evenheat ovens (at least the model I have) descend from the top of the oven chamber to about the middle of the chamber it takes it's most accurate reading from the middle to the top. The chamber can be 50˚ cooler at the bottom of the chamber where the knife sits. In my oven the salt melted at 1530˚f. So if I want 1475˚ in my oven where the blade sits I need the readout to show 1530˚. Also, because my tongs act as a heat sink when taking the small coupons out of the oven, I was instructed to drill a hole in the corner of the coupons and add a stainless wire handle with which to remove the samples. So I ran another set of coupons and the results were still lack luster. I called Ed back and he told me to add another 50˚. He also told me to skip the normalization and thermal cycles. I did and the results are below. At 1615˚ on my readout I am getting 67+ HRC. So if anyone is having trouble getting their steel to harden, make sure you examine all the steps of your process and the calibration of your oven before declaring that the steel is crap.

Here are my updated results:
gB1q1nk.jpg
Click to expand...
Marc, what size tray and how much table salt? 1 Tablespoon?

also to add about to the details and examining all the steps, I've been having similar difficulties with 52100.
After a few days of effort and several failed attempts, with the help of a local knifemaker friend, we were able to trace the hardness reading problems to my failure to grind off all of the decarb before I took hardness readings.

Seems simple and straightforward, but I don't do alot of homogeneous steel or on a regular basis, so the important step got overlooked. I did grind off the decarb (or so I thought), I just didn't go deep enough.
 
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i4Marc said:
Ok, I just wanted to refresh this thread so it isn't left open ended. I'm sorry for the delay in posting but I've been busy. I thought it was important to bring this thread up to date because the topic about suspicion of steel quality and certain vendors comes up frequently. As most of us with a little experience know by now, many variables affect the outcome of our efforts. What is easily blamed on the steel can often be traced with a little effort to something else. Because the reputations of people and businesses can be unfairly tarnished it is important that we (should) strive to always be fair and thorough in our troubleshooting.

In my particular case, I was having a hard time getting my W2 to harden. The steel came from NJSB. After running a few sets of coupons with unsuccessful results I called the office and they put me in touch with Ed Braun who seems to be fielding their heat treat questions. Ed suggested I do a salt test. This involves making a series of small trays out of SS foil and filling them with table salt. Table salt melts at 1475˚f. Starting at 1475˚ on your oven readout, put in a new salt tray at 5˚ increments until the salt melts. Because the thermocouples in Evenheat ovens (at least the model I have) descend from the top of the oven chamber to about the middle of the chamber it takes it's most accurate reading from the middle to the top. The chamber can be 50˚ cooler at the bottom of the chamber where the knife sits. In my oven the salt melted at 1530˚f. So if I want 1475˚ in my oven where the blade sits I need the readout to show 1530˚. Also, because my tongs act as a heat sink when taking the small coupons out of the oven, I was instructed to drill a hole in the corner of the coupons and add a stainless wire handle with which to remove the samples. So I ran another set of coupons and the results were still lack luster. I called Ed back and he told me to add another 50˚. He also told me to skip the normalization and thermal cycles. I did and the results are below. At 1615˚ on my readout I am getting 67+ HRC. So if anyone is having trouble getting their steel to harden, make sure you examine all the steps of your process and the calibration of your oven before declaring that the steel is crap.

Here are my updated results:
gB1q1nk.jpg
Click to expand...

those results suggest that the carbon level is low, probably about 0.7% or so. Higher carbon levels lower optimum aust temp.
 
Warren, I probably got this batch of W2 before I knew to get the certs so that was a while ago. Consequently, I cannot confirm your hypothesis. But in theory you are correct.
 
As a new maker, one looking to get into HT his own stuff soon, this thread was so incredibly interesting. Thank you everyone for the lengthy responses and follow ups, wow.
 
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