Tungsten & Tungsten Carbide Alternatives 4

[blueandwhiteg3]

Can anybody suggest alternative metals/alloys with properties in terms of hardness, impact resistance, stiffness, abrasion resistance, etc. in the range of tungsten and tungsten carbide?

I'm specifically looking for a metal or alloy here, not a ceramic or composite. Cost is not a major issue. Lower density would be nice.

Molybdenum runs a bit soft for my tastes.

 

[TVP]

Do you mean metallic tungsten or the composite of tungsten carbide particles embedded in a cobalt matrix (typically called tungsten carbide but the real name is cemented carbides)? If it is the former, you may be able to find a nickel or molybdenum based alloy that is similar. If it is the latter, then no, there is not an alternative system that is comparable. However, there are many different grades and producers of cemented carbides so you should be able to find alternatives that provide similar performance to an existing product.

 

[swall]

You might consider 98M2 Stellite as a replacement for tungsten carbide. It is available as casting and powder metal product. Like tungsten carbide, fabrication will involve grinding; brazing is used to join it to a substrate.
Deloro Stellite is one source.

 

[arunmrao]

Co based alloys,can meet your requirements and they are expensive too!

I have not failed. I've just found 10,000 ways that won't work." — Thomas Edison
_____________________________________

 

[blueandwhiteg3]

Thanks for the replies, and sorry for any lack of clarity here.

I want a solid metal/alloy here, NOT a composite, cemented carbide, coating, plating, or other. I know people will want to mention these options, and they are interesting, but not what I'm asking.

I like the hardness of tungsten and of tungsten carbide even more. The goal is extreme abrasion resistance. I like the impact handling of W, although most metals are acceptable here, save for really brittle things like pure chromium. The stiffness in W is also great.

My biggest complaint about W/WC is the density. I dislike the high melting point of W/WC, although this can be worked around. I would also love a lower cost, but so would everybody! I'm prepared to pay plenty more for an improvement over W if it can be had.

I looked 98M2 Stellite and it certainly looks like it might have compelling properties. A quick compositional review suggests that it's got a little of many metals I was thinking about... boron, carbon, tungsten, vanadium, molybdenum, manganese, chromium.

Any ideas on the potential for hot isostatic pressing of 98M2 Stellite powder?

Other notes on other alloys?

 

[tomwalz]

Stoody makes a huge number of alloys and is very creative in how they do it. Try

Louw De Jong
Stoody Deloro Stellite
604 463-2140
ldejong@stellite.com

Not sure if it fits but cermets have a much lower density than tungsten carbide.

Have you tried some of the new nano-materials and similar?

Tom


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[CoryPad]

If you want a solid alloy with high hardness, then steel seems like your best best. You can harden steels to > 700 HV, although this is less than the > 1200 HV for cemented carbides.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[arunmrao]

You can make an alloy,having 15% Cr,3% Mo,6% Va,1.5%W 2.5%C . This can be hardened and is extremely wear resistant.

Perhaps Cory too might have some such chemistry on his mind.

I have not failed. I've just found 10,000 ways that won't work." — Thomas Edison
_____________________________________

 

[blueandwhiteg3]

I am trying to reach some people at Deloro Stellite, but I have yet to speak with the right technical contact.

One of the applications for this material is hot isostatic pressing. I may even be interested in producing a metal-ceramic matrix or cermet, should the metal alone be unsuitable. However, this arena gets very complex very quickly, so I am trying to just focus on the metal aspect of things.

Ideally, I would like a solid metal which I can use at very low thicknesses without becoming too brittle. I would rather have a dense-but-thin material than a light-but-thick material, hence my focusing on the metal aspect of things. However, the stiffness and impact resistance are the primary limitations in making a thin material, and will only be worked out through real-world testing.

I also could have my guys with the electric arc furnace whip up any range of alloys for me on a custom basis, although it would be nice to work with something off the shelf to get started.

I would love to hear about any alloys not from Deloro Stellite if anybody would care to share. I am also curious about nanomaterials.

 

[CoryPad]

You mention brittleness - any metal with hardness > 600 HV is going to be brittle.



Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[blueandwhiteg3]

I would not consider tungsten to be brittle, given my application. Comparatively, I would consider pure chromium to be brittle.

Brittleness is hopelessly subjective, but despite my best efforts, I find my needs are not precisely quantified by any regularly measured value.

 

[arunmrao]

blueandwhiteg3,
if you can let us know more about the application that you have on mind,perhaps you could evince better response. As I see the whole range of wear resist materials have been presented. Maybe it does not meet your requirements.

I have not failed. I've just found 10,000 ways that won't work." — Thomas Edison
_____________________________________

 

[NickE]

I dont think that WC is available as a single material, in that case it would be considered a ceramic. the only times I've ever seen, heard, or experienced the use of WC it has been in a composite with nickel, cobalt, or other metal.

 

[blueandwhiteg3]

I have identified a few different alloys with melting points and hardnesses of interest. I am still gathering data on abrasion resistance and toughness.

My application for this material would involve hot isostatic pressing and a few other processes.

Here is a working list of alloys:

Deloro Stellite Stellite 98M2 - 2327° F liquidus, 8.63 g/cm^3, 58 Rockwell C hardness.
Deloro Stellite Deloro 50 - 1945° F liquidus, 8.14 g/cm^3, up to 58 Rockwell C hardness
Deloro Stellite Delcrome 93 - 2219° F, 7.77 g/cm^3, 58-65 hardness
Deloro Stellite Nucalloy 453 - 2260° F, 8.10 g/cm^3, 43 hardness
Deloro Stellite Nucalloy 488 - 2260° F, 8.10 g/cm^3, 45 hardness
Deloro Stellite Nucalloy 488V - 2230° F, 8.10 g/cm^3, 45 hardness

The Deloro 50 is interesting, as it has a low melting point, yet excellent hardness.

 

[blueandwhiteg3]

The guys at Deloro Stellite are proving great to work with. My applications are rather new for them too, but they're working hard to put together the data and identify which alloy(s) I should be trying out.

Do they have any serious competitors I should be checking out?

 

[calphad]

The closest alternative to cemented carbides you can get, when it comes to the resistance to abrasive wear, is one of super high-speed steels such as, say, CPM Rex 121 or CPM Rex 86. These grades contain a relatively high volume fraction of very hard vanadium-rich MC primary carbides and tungsten-molybdenum-rich M6C primary carbides. The machining and toughness characteristics of super high-speed steels are superior to those of cemented carbides, and the price is also lower (approximately one order of magnitude).

Alojz Kajinic, Ph.D.

 

[blueandwhiteg3]

This is really interesting, I love it when people add this kind of data. I had not been aware of specific grades of very hard steels. I have been aiming to use materials with a liquidus of 2330° F or less.

One of my concerns about a steel is corrosion. While I'm not expecting any acids or anything, moisture is a possibility, perhaps even extremely brief salt water splash exposure. This would not be persistent, but I would hate to have a carbon steel rusting on me here.

I will look into them further and see what I can find. Meanwhile, Deloro Stellite also has several very promising options, and I am arranging to test a small range of them from very hard to less-hard-but-more-tough.

 

[blueandwhiteg3]

Alojz, I'm a little curious... if these materials are so much better than cemented carbides, why are cemented carbides still being widely used?

I also wanted to add that I am are obviously very interested in cost, but the size, volume, value, etc. here does mean that limiting cost is not the primary objective.

 

[TVP]

The reason cemented carbides are still widely used is because they have better wear resistance and higher stiffness. calphad said that the super HSS are superior in machinability and toughness, not the other two parameters.

 

[blueandwhiteg3]

Yes, that's what I suspected... but it was not stated, thus I kind of had to ask more generally. There are often subtle, non-obvious differences in materials...