Weird lines on knife bevel?

[Diego_B]

Hey guys. So the other day I had some blisters show up on my bevels from a bad ht and I had to redo my it. But the day before yesterday I was heat treating a camp chopper type blade and after the ht I had some odd worm like lines running Parallel to the cutting edge. I’ve never seen this before and I’m confident that they aren’t blisters because from what I can tell blisters are like dots and bubbles on your blade. However these are LINES on my blade that worm their way up all the way to the tip. You can’t feel them with your finger or anything and they aren’t very noticeable unless you are holding them out directly to the light. I found out today that I can grind them out fairly easy on a 120 grit belt and I was going to call it solved, but I’m afraid that I may be erasing something that is trying to tell me I did something wrong, this is all after ht and tempering. Now then I looked at another blade I am making from the same stuff and it has the same lines in it as well except I haven’t ht that blade yet, only normalized it 3x. So I’m not sure what’s up but I’ve ruled out blistering, but is this something else similar to that? I also dipped it in the acid to just see what it did after grinding on side of the lines out and the acid showed no sign of the lines after grinding. However when I do this with a blade that has blisters the acid will still resurrect the blisters even after grinding. The steel I’m using is SKS51 from an old sawmill blade, yes I confirmed it is SKS51 with the saw blade manufacturer. Also yes I know I should probably be sticking to simpler steels and I do mainly use 1084 however I just gave it a go for the sawmill blade cause why not? But right now I’m honestly pretty confused and the only thing I can think of right now is that it’s the steel itself or it was because of the normalization cycles I ran it through. But I was being very careful to watch my heat on the normalization cycles so I don’t think that’s it?

 

[AVigil]

I just gave it a go for the sawmill blade cause why not?

Now you know why.

The most obvious answer is chuck it, no one really will know what has happened to that saw blade or have experience with it, if it is even the correct steel you think it is.

 

[Diego_B]

Yeah I see that really I’m just asking for something like this too happen. But I just thought I might as well ask too see if anyone has had something similar happen before. Also in the case that the same thing does happen again but with a known steel.

 

[Natlek]

Hey guys. So the other day I had some blisters show up on my bevels from a bad ht and I had to redo my it. But the day before yesterday I was heat treating a camp chopper type blade and after the ht I had some odd worm like lines running Parallel to the cutting edge. I’ve never seen this before and I’m confident that they aren’t blisters because from what I can tell blisters are like dots and bubbles on your blade. However these are LINES on my blade that worm their way up all the way to the tip. You can’t feel them with your finger or anything and they aren’t very noticeable unless you are holding them out directly to the light. I found out today that I can grind them out fairly easy on a 120 grit belt and I was going to call it solved, but I’m afraid that I may be erasing something that is trying to tell me I did something wrong, this is all after ht and tempering. Now then I looked at another blade I am making from the same stuff and it has the same lines in it as well except I haven’t ht that blade yet, only normalized it 3x. So I’m not sure what’s up but I’ve ruled out blistering, but is this something else similar to that? I also dipped it in the acid to just see what it did after grinding on side of the lines out and the acid showed no sign of the lines after grinding. However when I do this with a blade that has blisters the acid will still resurrect the blisters even after grinding. The steel I’m using is SKS51 from an old sawmill blade, yes I confirmed it is SKS51 with the saw blade manufacturer. Also yes I know I should probably be sticking to simpler steels and I do mainly use 1084 however I just gave it a go for the sawmill blade cause why not? But right now I’m honestly pretty confused and the only thing I can think of right now is that it’s the steel itself or it was because of the normalization cycles I ran it through. But I was being very careful to watch my heat on the normalization cycles so I don’t think that’s it?

Did you forge that steel from old saw ? If not , why you do 3 x normalization ? What you use for HT knife and for normalization ? Electric HT oven or two brick gas furnace ?

 

[Diego_B]

This is stock removal from it. I normalized it because of the stresses that may have been put on it from its previous life. I normalize everything I do. For the heat treat I used my two burner propane forge set on only one burner. I have another blade that I forged from the same material and I am planning on heat treating it tomorrow and see what happens. I also will probably put on a quick edge and test out the blade that had the lines on it. I was reading another recent thread on here that was discussing a line on his Damascus blade and right now I’m assuming that we have the same problem because he has the same line as me, except I have several little ones that worm up the bevel to the tip. As of right now I figure the lines are due to uneven heating during quench and they are cool spots? Or it may just be because of the property of the steel. Because I do have another unheated blade with the same lines.

 

[Natlek]

Forget previous life of that steel and forget that 3 normalization cycle with burner propane forge Cut one blank ,grind bevels and HT it and see what you will get