Nitro V ht problems. Pics now

G

godogs57

Joined
Apr 16, 2004
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Posted a couple of weeks ago about some paring knives that just wouldn't sharpen made from the subject steel. Folks were kind enough to respond with questions and observations. There were questions wondering if it was indeed Nitro V...possibly 1095? Grain growth was also mentioned.
Today I snapped one of the blades on purpose in my big vise. To be honest, I did not see what I thought was grain growth. Still at a loss as to what happened. My first ever "flop" of any kind with stainless in 40+ years.

pics for your comment. It broke right about at the ricasso.

IMG-4333.jpg


IMG-4332.jpg

IMG-4331.jpg
 
The grain looks decent from what I can see with the pictures. It's hard to get good pictures of the grain, a macro lens or setting really helps!

I am at a loss, too! Unless it was a bad batch (I've read about bad 1084 batches and some 80CRV2 that was super coarse even after extensive cycling), I am stumped! I am going to guess mislabeled steel, maybe another stainless that needed a hotter temperature or something weird, or the edge got too hot and lost the temper?
 
I thought the grain looked fine as well. The fact that every blade cut and ht from that bar was unsharpenable leads to only two guesses. Mislabeled steel or incorrect heat treat. As mentioned earlier, I followed Larrin’s ht protocol to the letter, as I have on every batch of the subject steel. Each batch turned out scary sharp, except this batch. Testing the hardness after tempering showed a consistent 62.0.

I’m flummoxed. Got another batch of paring blades in the works currently but I’m going with my tried and true CPM154 until I figure out what happened.
 
A couple of questions for clarification. Have you used Nitro-V in the past? You mention doing stainless in the past, but not this particular steel. What do you mean by unable to sharpen? I'm assuming you can grind the bevels to an edge, but the edge won't last, or wont' get fine enough to cut? Did you Rc the blades for hardness?
The grain in the photos doesn't look horrible, but in the second photo it looks a little more course near the edge. It could just be the lighting. Did you grind after HT or prior?
 
Yes I’ve made a hundred or so Nitro V blades in the past. All others have turned out just fine. This was my first ever hiccup with any stainless in 43 years. CPM154 is my primary steel. This batch of four paring knives all were 62.0 Rc on my hardness tester. Because it has a tendency to warp, I grind after heat treat on this steel. The edge was sharpened on my Wicked Edge and the result was a “gritty” edge that I figured to be massive grain growth, as did others who responded to my previous post. Last week I took one of the blades and snapped it to examine the grain, which appeared good, hence me posting these pics. Hit me up at the Guild meeting at the Blade Show Atlanta…..I’ll be there for the morning meeting. I’ll be glad to show it to you.
 
godogs57 said:
Yes I’ve made a hundred or so Nitro V blades in the past. All others have turned out just fine. This was my first ever hiccup with any stainless in 43 years. CPM154 is my primary steel. This batch of four paring knives all were 62.0 Rc on my hardness tester. Because it has a tendency to warp, I grind after heat treat on this steel. The edge was sharpened on my Wicked Edge and the result was a “gritty” edge that I figured to be massive grain growth, as did others who responded to my previous post. Last week I took one of the blades and snapped it to examine the grain, which appeared good, hence me posting these pics. Hit me up at the Guild meeting at the Blade Show Atlanta…..I’ll be there for the morning meeting. I’ll be glad to show it to you.
Click to expand...
Ok, that is strange. I have never worked with Nitro V, but know it's similar to my standard, AEB-L. I guess it either gets chalked up to bad batch of steel or a gremlin. 😁
 
godogs57 said:
Posted a couple of weeks ago about some paring knives that just wouldn't sharpen made from the subject steel. Folks were kind enough to respond with questions and observations. There were questions wondering if it was indeed Nitro V...possibly 1095? Grain growth was also mentioned.
Today I snapped one of the blades on purpose in my big vise. To be honest, I did not see what I thought was grain growth. Still at a loss as to what happened. My first ever "flop" of any kind with stainless in 40+ years.

pics for your comment. It broke right about at the ricasso.

IMG-4333.jpg


IMG-4332.jpg

IMG-4331.jpg
Click to expand...
Could be mislabeled steel however it’s likely not 1095 if it tested 62 hrc and you followed a Nitro V protocol. I’ve had two instances of mislabeled steel both times the hrc missed the mark by at least 5 points. I recently sent them out for XRF to confirm because I needed to know was it me or the steel. Turns out I was right two different steels than what was ordered.
 
Thescrawnylumberjack said:
Could be mislabeled steel however it’s likely not 1095 if it tested 62 hrc and you followed a Nitro V protocol. I’ve had two instances of mislabeled steel both times the hrc missed the mark by at least 5 points. I recently sent them out for XRF to confirm because I needed to know was it me or the steel. Turns out I was right two different steels than what was ordered.
Click to expand...
Agree. I've made enough Nitro V blades to know if I messed up. But....I CAN mess up as good as anyone else. Got a couple of other bars. Will make up a couple more and see how they turn out.
 
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