Need help finding proper alloy

[MacGyverS2000]

I hope this is the best forum... doesn't seem to get too much activity.

I'm looking for the most abrasion-resistant steel alloy I can get my hands on for a reasonable price. Suggestions?

Some helpful info... the application will involve close proximity to hand-held high-speed steel (HSS) tooling and sandpaper of various makeups (garnet, silicon carbide, etc.) while being spun on a lathe. As these will be used as sizing guides, the intent is to provide as much resistance to the tools and sandpaper reducing the diameter of these pieces as possible.

I realize there may be a trade-off in abrasion resistance versus cost to mill these guides, but I need as much info as I can get so I can make an informed decision. Increased costs of, say, 10% to mill a significantly more resistant guide is perfectly acceptable... a 100% increase may or may not be, depends on the final cost.

I hope all of that is clear.

Thanks!

Dan - Owner

http://www.Hi-TecDesigns.com

 

[metengr]

Investigate the Hardox or Leeco steel abrasion resistantance grades

http://www.hardox.com/

or

http://www.leecosteel.com/products/abrasion-resistant-steel-plate.html

 

[MacGyverS2000]

Thanks for the suggestions, met. Am I on the right track thinking an abrasion-resistant metal is the way to go, or am I merely throwing money at a problem that will likely have little effect?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[dgallup]

You might want to consider a hard plating or welding on a hard facing like stellite.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[metengr]

I did think about a hardfacing on carbon steel. Try AR plate and the hardfacing in two separate applications and see which performs better. As with most folks, I would expect you have more time than money.

 

[MacGyverS2000]

This needs to be a quick process, i.e., a machinist pulls some pre-made bar stock off of the shelf and begins cutting these pieces... thousands will be made, all around the size of a dime, and the cost should be in the tens of pennies range for each one.

Here is an example:

Dan - Owner

http://www.Hi-TecDesigns.com

 

[EdStainless]

In order to get them cheep a surface treatment may be the best bet. If an alloy has good abrasion resistance it will be difficult to machine. Use a reasonably tough, med strength steel (maybe microalloyed grade) and then batch surface treat them.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[TVP]

I agree with Ed, a coating might be the lowest cost option. Some possibilities:
[ul]
[li]nitriding (specifically salt bath nitriding like Kolene QPQ)[/li]
[li]electroless nickel[/li]
[li]Cr plating (hard or industrial Cr, 25 micrometers minimum)[/li]
[/ul]

 

[moltenmetal]

Another vote for surface coatings or surface hardening rather than machining a hard alloy. Nitriding, carbonitriding, or vapour deposition coatings such as what they put on HSS tooling these days for a dime a dozen. Bonus is that this type of process won't change the as machined dimensions enough to care about.

 

[MacGyverS2000]

Is the nitriding / carbonitriding process fast to set up? In other words, is it accomplished by dumping everything in a basket and dunking in a chemical bath, or is it more involved such as needing to hook up each part to an electrode? If it's the latter, cost would likely shoot through the roof and make this a pointless exercise.

What is the typical depth of the nitride layer? If the sandpaper or hand tools can quickly scrape it off, it may also be a low ROI for the time / money.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[EdStainless]

Some treatments can be done in pack, mixing parts and a process compound in a box and then heating.
Others would require the parts being placed on hooks on a rack, simple and fast.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[TVP]

As Ed mentioned, the processes are fast. Salt bath nitriding involves immersing parts (in bulk) into molten salt baths, usually as part of an automated or semi-automated process. Process time is on the order of a couple of hours. Gas nitriding or ion nitriding (aka plasma or glow discharge nitriding) usually entail racking parts. Carbonitriding is done in a furnace similar to conventional hardening or case carburizing, just with the atmosphere modified to include nitrogen. Parts can be dumped into a basket/tray (bulk) or more precisely placed into a homogeneously arrayed common orientation, but this does not necessarily make it expensive.

 

[MacGyverS2000]

Looks like I need to find a competent shop, throw some of these ideas at them, and see what sticks to the price-containment board. I'd really like to do this, but time is always a factor with my pet projects. I suspect I'll make 50 of these kits to start, each kit would have around 200-250 of these little doodads. Yeesh... now that I think about it, that's a lot of little doodads.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[MiketheEngineer]

Call your vendor??

 

[MacGyverS2000]

I don't have a vendor for this line of work, Mike, so it's likely going to go to a (semi-)local job shop. I'll keep my fingers in the pie to make sure it's done correctly, but most of the work is going to be on my shoulders for this one.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[MikeHalloran]

Let's back up a little.
Hand-held HSS tooling is going to lose its edge or fracture the first time it caresses AR steel.
That may not be what you want to happen.

Quantity 10,000 little doodads just screams "screw machine".
Screw machines can deal with leaded steel, but they like leaded brass a lot better.
Once you get them set up, and I think you can lease them in tooled condition, a superb machinist is not necessary; you just need a person to feed them bars, check the parts to detect worn or broken tools, change the tools, shovel out the parts and chips, separate the parts from the chips, clean the parts, clean and dry the chips, and pack the chips. You pack the chips because you can buy brass on a net part basis, i.e. you send back clean chips and get a credit against the brass cost.

Oh. Hardness and abrasion resistance. Nickel plate the brass doodads.




Mike Halloran
Pembroke Pines, FL, USA