Tungsten vs Tungsten carbide

[chuy]

What is really the differences? I was looking at some rings and some were tungsten. I saw that tungsten was scratch proof since it is a 9 in mohs scale. But the whole myth that tungsten are indestructible which is false because they can shadder when huge force is applied. Wait, really? SHADDER? Then what were the soviets thinking of using tungsten cored 14.5x114mm for armor piercing????? I soon found out that the rings are made of tungsten carbide which is an alloy instead of a metal. Do rings even come in pure tungsten form- like the non-shadderable ammunition the soviets used? Non -carbide.

I want a pro and con list of each since I am very confused.

It seems tungsten carbide is weaker since it has a lower melting point than pure tungsten. 2870 C Vs 3422 C

 

[[TW]Wilsonam]

Soviet APCR (tungsten-cored) ammo shattered just as much as anyone else's. And the armor penetration modeling in RO2 does take account of projectiles shattering

I haven't checked, but from memory, people work the alloy because (lower melting point) it is easier to work. You'd need to check things like the hardness, density and ductility to compare them properly. And I'm too lazy to look them up for you

 

[chuy]

I thought that ceramics like tungsten carbide shadders while the pure form doesn't. Or I may be wrong. I know that every metal will chatter but not as easily. You can basically get some pliers and shatter a carbide ring. I doubt they would use that against hardened armored tanks traveling at 1010 m/s (3600 ft/s). People even report they dropping their carbide rings in cement and they wil shatter. I doubt I would be effective against tanks. Unless pure tungsten just bends like other metals. Or is tungsten, no matter what form of it, will shadder?

 

[[TW]Wilsonam]

Any metal projectile can shatter. Well, ok, modern long-rod penetrators usually ablate, not shatter. One of the most devastating (WWII-era) penetrations happens when a projectile shatters but still penetrates - lots of bit flying around

 

[Nestor Makhno]

Only Wilsonam would put a smiley at the end of that sentence.

 

[chuy]

I just a bit of research and found out that tungsten carbide, the thing that rings are made of have a hardness scale of 9 while pure tungsten is 7.5. The carbide is scratch resistant but can shatter. Pure tungsten is more prone to scratching but will never shadder, only bend or dent. So I probably think the soviets used pure tungsten on their 14.5mm. Makes sense since harder things in the moh scale tend to shadder higher they are. For example, diamond. Lower in the moh scale dont shadder but bend for example titanium. I also compared the melting point of both tungsten vs carbide and found out that the carbide had a lower melting point than its pure form. 3422 of tungsten vs 2870 of carbide. Probably so they can make shaping the ring better?

 

[[TW]Wilsonam]

And projectiles that are too hard are not a good thing. Compare steels used in armor - the Germans face-hardened plate when it was less than 30mm (or 50mm, can't remember, need to check). The Soviets also used high-hardness steel for thin plate. The idea was that it wouldn't stop large rounds - but it was more likely to shatter incoming small-caliber projectiles. Against large projectiles, the armor would just shatter (for ref, see the PzBefWg 1 at Bovington).

 

[Zetsumei]

the main difference between tungsten and tungsten carbide is in the difference of its name.

Metals by themselves often have a very organized symmetric matrix. But a cleanly organized matrix makes it easy to deform. Look at this set of coins below.

Say you press press one row of coins from the left, you will then easily slide an entire row of coins out.. A similar thing can happen in a lot of metal structures, allowing them to adapt to a new shape to distribute their stresses better.

Adding carbon in there is basically to make the matrix less perfect, by essentially putting barricades in the matrix that stop it from deforming. Imagine in the above picture if you added some big or small coins in the mix, it would be less easy to slide one row out essentially.

If a material is changed so it cannot deform as easily generally that generally means its hardness increases, however if stresses become too high the material cannot slide or deform as easily in a different configuration making it more likely to simply break off aka making it more brittle.

In the case of tank rounds, you don't want the rounds to deform and become a flat pancake when hitting the outside of a vehicle. And you don't want it to simply shatter on impact. So like with a lot of materials you try to find the correct mix of materials, physical treatments and heat treatments to get something that fits your particular desire.

You can expect something like tungsten carbide for the application of rings to be different to drilling tools or ammunition. Beside that often people call tungsten carbide simply tungsten as well to add confusion to the mix.

 

[dibbler67]

Trying to learn about solid solution strengthening was one of the things that made me realize I really didn't want to become an aero engineer

 

[Zetsumei]

Material sciences is a different study from earospace or mechanical engineering though . You would probably only learn enough to understand the basics good enough to not do stupid stuff when finding material in a brochure or connecting stuff together.

 

[dibbler67]

Yes, it was one of an assortment of classes I had to take in the latter part of my sophomore year. Even at a basic level I failed it... and would have had to take it again

It turned out that the only class that semester that interested me was the intro to C++ course anyway, so I thought why bother retaking a class I hated?

I did learn a little bit though