Vein-like pattern in D2

[Randy Wirtz]

I'm hoping to get some insight here on a pattern I see frequently on my D2 after heat treat. The best way to describe it is vein like in appearance. Most of the time this pattern is virtually gone after finish sanding. Recently, I had a blade that this pattern still remained fairly noticeable even after finish sanding.

The blade is heat treated at 1850 for 30-35 minutes and protected in a foil pouch. Please see attachment below. Thanks

Randy

 

[Willie71]

It’s probably alloy banding, or carbide segregation. D2 is pretty high alloy, relatively, and uses traditional cast production methods. I see similar effects in the non pm cru-wear. The pm versions don’t have this effect.

I’m sure one of the metallurgists will be along shortly if I’ve got this wrong.

Edited to correct typos.

 

[Larrin]

In the polished condition you are probably talking about orange peel which can be exacerbated by the segregation and banding.

 

[Randy Wirtz]

FYI this veining does not show up during the polishing. It appears after heat treat. It generally diminishes after finish sanding. Here is what it looks like immediately after heat treat. Compare to pic in original post after finish sanding.

 

[JTknives]

That’s just oxide colors for the foil wrap and the little oxygen in the packet.

 

[Randy Wirtz]

It’s probably alloy banding, or carbide segregation. D2 is pretty high alloy, relatively, and uses traditional cast production methods. I see similar effects in the non pm cru-wear. The pm versions don’t have this effect.

I’m sure one of the metallurgists will be along shortly if I’ve got this wrong.

Edited to correct typos.

Would you mind clarifying your last two sentences. Not for grammatical reasons, but just that I may understand more clearly. Thanks for chiming in.

 

[Willie71]

Would you mind clarifying your last two sentences. Not for grammatical reasons, but just that I may understand more clearly. Thanks for chiming in.

I see this “patterning” in cast cru-wear. The PM versions, cpm cru-wear, and pm z-wear have much finer grain and carbides, even though they are the same alloy composition, so they don’t show the banding.

 

[Nathan the Machinist]

I get that sometimes, I think it might be an interaction between the foil and the steel. There's something in the foil designed to consume oxygen (titanium perhaps?) that may react with the steel. It might not sand off but it will grind off. D2 alloy banding is much smaller and harder to see.

 

[Randy Wirtz]

I see this “patterning” in cast cru-wear. The PM versions, cpm cru-wear, and pm z-wear have much finer grain and carbides, even though they are the same alloy composition, so they don’t show the banding.

Thanks for the clarification Warren.

 

[Randy Wirtz]

I get that sometimes, I think it might be an interaction between the foil and the steel. There's something in the foil designed to consume oxygen (titanium perhaps?) that may react with the steel. It might not sand off but it will grind off. D2 alloy banding is much smaller and harder to see.

In your experience, is there any way around or minimizing this interaction?

 

[Nathan the Machinist]

In your experience, is there any way around or minimizing this interaction?

Sorry no, not that I know of.

 

[Randy Wirtz]

Thanks Nathan