1075 won't harden

Milt

Milt

Joined
Nov 16, 2008
Messages
260
I made a large blade from 1/4" 1075. I have heat treated it three times. It just won't harden. I tried the usual 1475 for 10 minutes. Then 1500 for 30 minutes. Then 1650 for 25 minutes. Quenched in McMaster- Carr all three times. I also did some 3/4" O1 shaft for a project this evening, and it hardened just like it is supposed to.


I am getting about 40 RC.
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I'm stumped.

Milt
 
Try a piece of scrap and quench in water. If it is going to harden that would prove it.
Have you used This bar of steel for other blades?
 
I ordered 1095 once, and when it came, it looked a little different than the other 1095 I had ordered in the past from the same company (the scale was different) I tried hardening a small piece of it in water and it wouldnt harden. I called the company and told them about this, and told them the color the end was painted, and they confirmed that I was sent the wrong stuff, and quickly sent me out some real 1095. Mistakes happen, and it seems it may have happened to you.
 
I considered the fact that I may have gotten the wrong steel, which has never happened to me in the past. This was a new batch, and from a new supplier who has probably the best reputation on this forum. I ordered some 1095 and one piece of 1075. Both were painted the correct color according to the brochure.

I have never quenched anything in water before. It is a violent process according to posts on this forum.


Thanks guys- I think I got the wrong stuff!

Milt
 
milt, if you want a free source for 1075 and you have a john deere dealer, you can get seperator discs from them for free. i picked up about 500# last spring. there are 2 numbers on the disc which are 3/16 thick and around 17" across when used. they rockwell around 56 to start with and i work it as is.

the numbers are SS0032 & N214190 and they are seperated by a j and d set inside a circle. if they say made in mexico, they are not 1075 and are junk. i get good results from knives i make. check out some of the vids at my website. here is one for now.
http://knifetests.com/kII.html its a little dark but i'm cutting a piece of free hanging paper.
 
Did you normalize it a bunch of times? Also, how fast is the oil that you are using?
 
I normalized it the first time- not the other two times. The oil is fast enough for 1095. It should have been hard after the 1st HT. I don't think it is 1075. I am going to test the 1095 later today.

Milt
 
I have a desktop hardness checker. Hardness on the edge is 48 so it is a bit harder on the edge. You can see that the dimple the diamond penierator leaves is deeper than it should be.

Milt
 
I had a piece of 1075 just the other day that I heated to non-magnetic and quenched it in Parks 50 and it tested at 63
I too think you have the wrong steel.
 
Milt said:
I have a desktop hardness checker. Hardness on the edge is 48 so it is a bit harder on the edge. You can see that the dimple the diamond penierator leaves is deeper than it should be.

Milt
Click to expand...

did you grind through your decarb layer to good steel before testing? with all of this heating you probably have a decarb layer at least half a milimeter thick, if you try hardness testing without removing that you are going to come up soft

-Page
 
I spoke with the supplier. He felt that the steel was indeed 1075, and that my problem was more than likely with the oil. I am going to try new oil and see if that makes a difference. I wonder how long oil lasts?

Milt
 
milt, i use canola oil and or a mix of motor oil and transmission fluid with the same results. its possible your temp was not hot enough but i myself go by color and not by a temp guage
 
I took off all the scale. This knife has a guard, so I can't take off any more metal necessary without making the guard fit poorly.

Milt
 
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