Flux-less welding and mystery steel

[Brian Dougherty]

Lat week I finally got around to trying to do a sam mai sort of weld where the center was going to be 15N20 and the outside was 1084. I have been wanting to try this for a while, and was hoping for a very dark blade with a shiny edge. I also decided to try welding this billet up with no flux.

 

I'm happy to report that the welding went great. It actually seemed easier to do than when I use flux, and the billet rings like a bell which I take to mean that there are not any large inclusions.

 

Now the bad news. After rough grinding, I did a quick test etch to see how well I kept the 15N20 layer centered. Much to my dismay, the center section of steel did not stay bright, but actually turned a shade darker than the 1084.

 

This was an new bar of steel I bought form Aldo a couple of months ago, and I put it with my 15N20 stock. However, it must be something else. I don't remember what else was in that steel order, but the end is painted red. Does anyone know what that color indicates?

 

The only red on his website is 15N20, and 1045, so I am now thinking I have cleverly created a blade with a whopping 1045 cutting edge (I can't for the life of me think of why I would have ordered 1045 for anything I do)

[Austin_Lyles]

I love fluxless welding. As to the steel in question, finish it up and then heat treat. It'll change. 15n20,for me at least, etches dark before heat treatment and will etch shiny afterword. However, you may be right!

Edited November 6, 2015 by Austin_Lyles

[Gary Mulkey]

Brian,

 

I can't help you with identifying the steel but I'm glad that you are having success with welding w/o flux. I was taught (years ago) that it was necessary to flux all welds but I haven't used any borax in years. If you have a good reducing atmosphere in the forge then it really isn't necessary like many of us were taught.

 

Gary

[Richard Furrer]

So....cut it in half

Place known 15N20 in the center and weld again and forge it out.

 

Ric

[Brian Dougherty]

Thanks guys!

 

Austin, I'll see what happens. I'll try quenching this weekend.

 

Gary, thanks for the encouragement. I welded up another billet tonight, and it seemed to go very well. No shadows in the blade at all. Very even heat color throughout while forging the blade to shape.

 

Ric, I guess that would have been the obvious solution. I've never been long on common sense

[Dave Stephens]

Austin is correct. 15n20 will look dark and 10xx light when just dipped in FC. After you HT and polish the blade it will reverse.

[Brian Dougherty]

I thought I would close the loop on this question by posting this pic. This is a shot of the blade after heat treat, and in nearly final polish. I'll touch the polish up after the guard fitting is done, but as you can see the colors became normal after the heat treat.