Black reside after resizing

[tactical_tech]

I picked up a hornady 3 die set for my .38spl and .357 magnum. It has the titanium nitride sizing ring. I took apart the dies cleaned them with brake cleaner and began to resize some brass after it had been cleaned in my sonic cleaner for about an hour.

Pick noticed after resizing I had black streaks on the cases, the reside rubs of easily. Thinking I didn't clean the die well enough I cleaned again with some rubbing alcohol as I was out of brake clean. Made sure the die had no residue on the sizing ring and tried again, the streaks came back right away. Some cases have barely any streaks others have a fair bit. Any ideas? Could it be residue from the cleaning process?

First picture shows the streaks, second shows after the marks are removed.

 

[bigedp51]

You cleaned the die twice and the cases still have black residue after sizing.

Your cases have a film left on them after sonic cleaning.

On the other hand when you polish the chrome on your car the rag turns black.

And sizing your brass with a titanium nitride sizing ring is also polishing your brass.

Lightly lube every 10th case and break in your "NEW" die, and then see what happens after a few hundred cases.

 

[tactical_tech]

You cleaned the die twice and the cases still have black residue after sizing.

Your cases have a film left on them after sonic cleaning.

On the other hand when you polish the chrome on your car the rag turns black.

And sizing your brass with a titanium nitride sizing ring is also polishing your brass.

Lightly lube every 10th case and break in your "NEW" die, and then see what happens after a few hundred cases.

Makes sense about the die polishing the brass. I did noticed the brass was shinier after resizing. Next batch I do I'll be sure to try lightly lubricating every 10th case and see how it goes. Thanks for the advice.

 

[bigedp51]

Don't tell anyone but I have titanium nitride and titanium carbide dies and once you break them in the "black" will fade into the sunset.

Below a Hornady titanium nitride die which is a coating process and the factory doesn't polish the die. You will polish the coating as you use the die and break it in. Don't tell anyone but I cleaned my die twice like yourself and then Googled the topic before my light bulb came on about the black on the case.

Below a Redding titanium carbide die, this type carbide has the titanium mixed with the alloy and is not a surface coating. The majority of carbide type dies tell you to lube every so many cases to ease the sizing operation and lube the inside of the die.

P.S. Remember not to tell anyone about this, because I never make mistakes with new fangled reloading equipment.

 

[tactical_tech]

Always makes a person feel better when someone else experiences the same issue. These are my first titanium nitride dies, have a few of the carbide and never experienced the black marks so it was a little weird. Now that I think about it, near the end of my session the marks were not as prevalent as when I started. Thanks for the advice again.
It'll be our little secret, even though this conversation never happened.