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NGSW Phase 2 Consolidation and info   Small Arms <20mm

Started 30/8/19 by gatnerd; 576075 views.
gatnerd

From: gatnerd

23-Nov

JPeelen said:

Elegant looks aside, from documents at the Bundesarchiv it is clear that SmKH cores are tungsten carbide.  We are talking of a material based on what Krupp offered on the commercial market as Widia ("wie Diamant", [hard] as diamond) for lathe cutting edges and the like.

Buffman has done a PMI (Positive Material Identification) Test on the SMKH core. 

The composition appears consistent with a Tungsten Heavy Metal composition vs Tungsten Carbide?

It's very different then M993 composition, and the armor manufacturer also believes it's some type of WHA alloy and not WC.

https://www.ar15.com/forums/Armory/Adept-Colossus-Beyond-Level-IV/10-540068/#i5795910

https://www.rembar.com/resources-technical-information-on-refractory-metals/tungsten-alloy-material-data-sheet/

As for how this mysterious super advanced AP projectile arrived in WW2, decades before WHA penetrators were fielded? I'm leaning on this:

stancrist

From: stancrist

23-Nov

gatnerd said:

Our Tungsten Heavy Alloy hypothesis is based on 3 factors

1. All the Buffman tested Tungsten Carbide cores have shattered upon encountering ceramic...

Okay, but that does not prove the SMKH core is not tungsten carbide.  There are a number of other possible explanations.

gatnerd said:

However, the SMKH tests, the core has zipped through the plate almost without slowing down, the the core has punched though the clay backing, and zipped out into the countryside behind. Highly suggestive that the core is still solid and not fragmented. 

Concur.

gatnerd said:

2. Adept, maker of the Colossus plate, also thought it could be a Tungsten Heavy Alloy.

Okay, but just because the armor maker "thought it could be" a Tungsten Heavy Alloy, does not constitute proof that it actually is.

gatnerd said:

3. Buffmans had tested the core, and shows a metal composition thats suggestive of WHA vs WC

Well, if metallurgical analysis shows the SMKH core to be WHA, then you have proper evidence and do not need a hypothesis, do you?

  • Edited 23 November 2022 22:22  by  stancrist
EmericD

From: EmericD

24-Nov

gatnerd said:

Buffman has done a PMI (Positive Material Identification) Test on the SMKH core. The composition appears consistent with a Tungsten Heavy Metal composition vs Tungsten Carbide?

Unfortunately, the PMI can't tell you if there are carbon atoms in the mix, so you can't tell between tungsten alloy and tungsten carbide ceramic with this test.

gatnerd said:

It's very different then M993 composition, and the armor manufacturer also believes it's some type of WHA alloy and not WC.

As Schnuersi already pointed out, Tungsten Carbide is a ceramic embeded in a metallic matrix, and the behavior of the "tungsten carbide" depends heavily on the choice of the matrix.

I would say that the SMKH is WC embeded in a Nickel - Copper matrix, while the M993 is WC embeded in a Cobalt - Iron matrix.

The M948 SLAP bullet is WC in a "pure" Cobalt matrix.

schnuersi

From: schnuersi

24-Nov

EmericD said:

I would say that the SMKH is WC embeded in a Nickel - Copper matrix, while the M993 is WC embeded in a Cobalt - Iron matrix. The M948 SLAP bullet is WC in a "pure" Cobalt matrix.

I agree.

schnuersi

From: schnuersi

24-Nov

Cobalt is the typical matrix material for tool grade WC. With qualities differing by Cobalt content and sintering pressure.

The numbers for the M993 seem pretty bad. Low grade material. Its an YG 15 (ish) grade. The low end of tool grade WC.

The numbers presented for the SmK(H) are indeed consitent with a WHA but it is extremly unlikely that at this point in time it really has been one. More likely is a WC with Copper-Nickel matrix.
Regardless of if the core of SmK(H) really is a WHA or not what is plain obvious from the two sets of numbers is the difference in actual W contend. The SmK(H) core is 90 W. The M993 core only 76 %. YG 15 WC is better than hardnened steel but as mentioned the poorest (cheapest) WC. It should be rather flexible and shatter resistant for a WC though. I think its pretty obvious that the material properties of the SmK(H) are better for violently punching trough stuff.

The M993 propably is a "victim" of modern engineering.
With the SmK(H) back in the day they tried the impossible and went full overengineering and money doesn't matter. Squeezing every little bit out of performance possible at the time out of it.
The M993 most likely has been designed and optimised to meet a specific specification, achieve this in the cheapest possible way and do nothing more. Obviously they succeeded in this sind everybody seems pretty happy with the result. The M993 and its counterparts in other nations are even happily issued en mass for use in MG belts. I doubt this would be the case with the SmK(H) nowadays.

gatnerd

From: gatnerd

24-Nov

EmericD said:

I would say that the SMKH is WC embeded in a Nickel - Copper matrix, while the M993 is WC embeded in a Cobalt - Iron matrix.

Are there any commercial examples of a WC - Nickel - Copper alloy? 

Googling, I can find a ton of WC - Cobalt alloys. 

But everything I turned up googling 'Tungsten Carbide Nickel Copper alloy' or 'Tungsten Nickel Copper alloy' all turn up numerous WHA ~90:6:4 alloys, but no mention of a Tungsten Carbide alloy with Nickel and Copper? 

EmericD

From: EmericD

25-Nov

gatnerd said:

Are there any commercial examples of a WC - Nickel - Copper alloy? Googling, I can find a ton of WC - Cobalt alloys.

It's because Nickel or Cobalt are not used to form an alloy with WC, but are used as a binder.

For example :

https://www.vistametalsinc.com/tungsten-carbide-grade-chart/

And a patent from 1977 that describes the use of Ni-Fe matrix with WC, with better mechanical results than Co matrix.

https://patents.google.com/patent/CA1090523A/en

schnuersi

From: schnuersi

25-Nov

gatnerd said:

Are there any commercial examples of a WC - Nickel - Copper alloy? 

Yes: W90NiCu specified in ASTM B 777-07
This is the alloy consitent with the numbers of the SmK(H). But I really doubt this is really the material.

Because there also is a sintered WC sinter material with the same composition.

The difference is in the way of production. To form a alloy all ingrediences have to be molten and mixed while in liquid state (this is the definition of alloy). Once they are coolded down and solidified the solid mixture is an alloy. This is not possible with all compositions of ingredience and all amounts. The trick is the right mixtures, correct temperatures and cooling speed. Its basically a science in itself.

A sintered ceramic is created from mixed powders. The ingredience are in solid form. Pressed into shape and then heated up under high pressure to bind the particles together to form solid part. Materials like Cobalt as used as the so called matrix which acts as glue. Its binds the other parts together. While sinter ceramics are pressed under high temperature this is usually still is way below the melting temperature of tungsten. So to really put the ingredience together you need something that at least gets soft and sticky. The matrix material can also provide other properties. In the case of Cobalt its elasticity. Which counteracts the brittle nature of WC.

This is why there is a difference between WC as a ceramic and W based alloys. Different methods of ceration and different matieral properties.
 

EmericD

From: EmericD

25-Nov

schnuersi said:

The M993 propably is a "victim" of modern engineering.

Well, the M993 was designed to defeat RHA (which is not really hard) even at shallow impact angle, so using a high cobalt fraction is sound engineering for me (WC with high cobalt fraction have a higher  transverse rupture strength).

WC with a lower cobalt fraction will be harder, but also probably less effective against the sloped armor of BMDs and BTRs (which were the primary targets of the M993).

Even if those numbers are difficult to compare (due to different test methods), the reported penetration capability of the Smk(H) is 13 mm / 30° of armor at 100 m, which is lower than the 18 mm / 0° of the M993.

Here is a comparison between the M993 core (WC cemented with Cobalt) and the WWII Russian BS-41 core (WC cemented with Nickel, like the Smk(H)).

https://www.researchgate.net/publication/310751663_Mechanical_Property_Comparison_of_the_Soviet_BS-41_and_the_US_M993_Armor-Penetrating_Cores

And an interesting presentation on the development of a 7.62 mm AP bullet, showing an open-jacket, tungsten carbide design.

https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2012/armaments/Thursday14062tran.pdf

The bullet was only 25.5 mm long, but could defeat >19 mm of RHA at 100 m. Now imagine the same bullet design, in .277" diameter, with a length >32 mm and increased impact velocity.

gatnerd

From: gatnerd

25-Nov

EmericD said:

It's because Nickel or Cobalt are not used to form an alloy with WC, but are used as a binder

Yes I had seen a number of WC Nickel binded ones. Whats throwing me off is the copper addition. 

That seems to appear only in various WHA alloys; I didnt see any copper options in the website you linked for example, just a bunch of WC-Nickel mixes sans copper. 

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