Looking for surface hardening of 304SS

[EdStainless]

We supply cold drawn 304 tubing. In the cold drawn condition the yield strength is roughly 110ksi (UTS 140ksi) and the hardness is about 30RC. The inside surface finish is 25microinches. Just for discussion let's say that the size is 1.000" od x 0.025" wall.
I have a customer that wants the inside surface harder for wear resistance reasons.
Limits, you bet. The outside should not get hardened. The id surface must not get rough. The id tolerance +/-0.002".

I have thought about EN plating, but that would also require a hone to finish.
Ion-nitriding would probably cause too much distortion.

Any thoughts? What have you seen out there that looks interesting?

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[BillPSU]

I have had the ID of a spinning mandrels hard chrome plated for abrasion resistance and partial corrosion resistance. The I.D. was honed after plating. The mandrels range from 5" I.D. x 12ft to 14" I.D. x 18ft. Just a thought.

 

[unclesyd]

I haven’t used this product but have heard some favorable results.

http://www.cccintl.com/

Here is another process for hardening SS. The link is extremely slow so give it time.

http://www.industrialheating.com/ih..._features__item/0,,99594,00+en-uss_01dbc.html

I have seen some interesting work by these people.

http://www.nitrex.com

Swagelok was advertising a process for hardening SS but my link is dead.

We had our best results in treating 304 SS for wear by the Kolene liquid nitriding process.

 

[rwelk]

Out of curiousity, why can the outside not be hardened?

 

[unclesyd]

rwelk,
Probably because of the comments I got on the first piece of SS that I had liquid nitrided.

"Where did you get that piece of crap, it uglies up the whole place"

A good comment except for the fact that the piece and others lasted 10 years instead of 6 weeks.