Flawed Panther Armor

[wokelly]

Before you begin reading I would like to state this is not my work. It is in fact a WWIIOL player “Scotsman” Derek, a very knowledgeable player and Forumie on the WWIIOL forums. His original article was a little rough, for example he had used short forms for a lot of the different types of metals used in constrcution, so I treid my best to smooth things out without changing the historical truths and facts he posted.

I also want to stress the information presented is 100% the work of the author. It was researched by him, and he wrote this all himself. All the connections are based on the facts he gathered from these tests done during 1940s. This info is not from any books out on the market and is likely not in any book. If anyone feels the need to use this information or do whatever with it, the author should be cited not only out of respect for the work he did but because not doing so is stealing his work, plagerism. The only thing I did was attempt to make the article flow better, but all the information is the result of the research done by Derek.

As the War dragged into the fifth year (1944) the Panther became plagued with Armor Quality issues that got progressively more common as more tanks were lost and the German industry sped up production to attempt to compensate. These issues effected all versons, but it is often thought the Panther A series was the most flawed armor wise.

The Panther suffered from many of the issues late war German tanks were facing, which was the result of the Germans changing the materials that made up their armor plating. Over the course of 1944 (most fingers pointing at the first months of 1944 rather then the end of 1944), as a result of material shortages Germany was facing, the Germans changed the alloy composition of their armor. Prior to this time the usual cromium-molybdenum type steel was used. All testing showed the plates to be sufficiently cross-rolled and both fracture and Charpy tests showed good fracture and shatter characteristics. By the beginning of 1944 things changed. Molybdenum was dropped and the plates started their trend to .5% carbon, 2% Chromium, and .14% Vanadium composition. Obviously Molybdenum was running short or had disappeared, and a substitute had to be found that was generally acceptable. The substitute was the move to vanadium.

This had a couple of effects. First high carbon is generally counter-indicated when it comes to obtaining good welds and shock/shatter performance. The deterioration of weld performance was witnessed in combat by both the German tank crews themselves and the Allies, and became a consistent feature in German armor samples from that point on. Good RHA (Rolled Homogeneous Armor) in the US or UK typically is no higher than .3% carbon at worst. Poor quality steel such as was found in some of the Italian AFV ran as high as .5-.6% carbon, and that of course yields generally horrid shatter performance. Instead of clean penetrations typical of “good” armor, large tears were seen in a plate with considerably more material or spall forced into the AFV.

Another issue with this composition is quench cracking. If armor plates are not quenched properly in manufacturing, it can generate cracks that are inside the plate and invisible to the human eye. Armor with interior cracking or non-uniform composition results in poor performance when it is hit with high velocity projectiles. This was especially true of plates greater than 2" in thickness, and with the Germans rushing out as many tanks as they could to counter the advancing Soviets and eventually the Advancing Anglo- American Forces, this led to a fouling of the quench cycle and also affected the quality of the plate. In case of a vanadium based steel, the Germans would have used less alloy to make it for a given weight, but between that and improper quenching they ended up with steel of inferior hardness.

Finally when combined with improper tempering, the Germans actually induce brittleness into what is already a faulty plate. The faulty tempering occurred in one of two fashions, either the plate was allowed to cool too slowly or the temperature ranged in the 400-1000 degree F range and didn't exceed that (Ideally they wanted 1200-1700 degrees followed by an appropriate quench). A further side effect of this is variable hardness in a plate of a given thickness, and again this was noted in the Panther's armor.

During the war, the US along with the UK, conducted periodic metallurgical testing of German, Italian and Japanese armor coupons throughout the war. A section of armor plate was flame cut from a captured vehicle in a way to make sure testing would not be effected, and in the case of the US was shipped to Watertown Arsenal or other US testing facilities.

The Panther glacis armor sampled in 1944 demonstrated all the characteristics of faulty plates, and more. Its not that the design of the plate or the weld was bad, but that the Germany was out of alloys required for good steel production, and the substitute process adopted was inferior in every way to the material it was replacing. When you throw bad manufacturing process on top of that (improper quench and temper) in hurry to get the vehicle out the door, you get what was seen in combat; brittle and shatter failures in plates which shouldn’t have those issues.

When we come off the glacis and to the side armor with much less thickness, its all a formula for outright disaster. In the case of some Panther Chassis, 75mm Sherman HE not only cracked the armor, but literally blew sections of armor plate off the tank, and obviously that should never happen on anyone's vehicle if the armor is up to snuff. It is quite easy to imagine the US officials were surprised to see such a large drop in quality, and they certainly noted in their reports that they believed Germany was (materially) approaching the end of the line.

This last paragraph is directly from the article:

Could Germany have avoided this fate? Yes...if they had more invested in quality control checks, re-quenching and re-tempering the armor would have eliminated some of these faults. That too was demonstrated in US testing. The barbarians were already at the gates though...and I am quite sure some of the T-34s rushed off the line early on would have similar problems. Heck some of the JS series tanks late in the war had severe quality issues...something which should have never happened given the strategic situation by that time.

Panther A series tank

In the first image there is two things of interest that can be seen.

First is the bow penetration, which is ragged and appears overcaliber in its characteristcs, which is an indication of overmatch. Second is the Panthers glacis pentration, which flies in the face of the commonly accepted norm that the glacis was invulnerable at normal ETO ranges, and for most guns on tanks in 1944 bar the M36 Jackson's 90mm, at even point blank.

What apears to be a chin on the mantle suggests a Panther G.

In the second picture we see once again the symptoms of below stardard armor that plauged german tanks in general from 1944 onwards. What we see is a massive weld failture and the treaing away of armor from the upper deck as well. I have no idea what hit the vehicle and in fact there might be instances against really large rounds where I could in fact stretch existing armor penetration methodologies to come up with plate failure that would indicate something somewhat smaller than seen in image one.The failure of the upper deck is a good indicator, however, of a bad weld and below average armor quality.

Sources:

WAL 710/542 - Armor and Welding on a Pz VI Tiger Tank
WAL 710/608 - Armor and welding on a Pz-IV etc.
ADA 954952 - Metallurgical examination of 3.25" thick armor from a german Panther tank
ADA 954940 - Metallurigical exmaination of armor and weleded joints from the side of a panther tank.

 

[Dheepan]

Very interesting.

So i'm assuming that the general assumption that German armour quality deteriorated towards the end of the war is correct.

But what month in 44? Towards the end?

 

[wokelly]

It was within the first months of 1944, but I am not sure specifically. Before D-Day for sure. Makes for interesting questions. How many of the Panthers created were created before the switch from Molybdenum to Vanadium and in general how large a Percentage of German tanks suffered from this weaker armor quality?

It also brings into question how much more effect the Sherman 76s and T-34-85s were against tanks like the panther. Its all good to compare penetartion tables but considering the German armor was flawed, that means that many guns on the SHerman 76 and the T-34-85 would have had better results against panthers, though more likely the mantle. After all it was a massive 100mm curved, but like all german armor as a result of the switch it would have been flawed.

I guess the greatest question would be how many tanks were severly flawed and other not so much. It seems that there were a number of factors that contributed to the flawed armor, and this may very well have resulted in different qualities of armor in the same tank type. This may mean that some tanks were more stronger then others, even if they were the same model!

Of course these are all questions and its up to the reader to draw their own conclusions and ask their own questions.

 

[Oldih]

general how large a Percentage of German tanks suffered from this weaker armor quality?

Not to mention possible flaws done by the fact they were needed on the front and production had to be put in haste. Good point about this is that for every 700 tanks Germany got out of factories Soviets got 2100 or more

And not to mention the funny fact that Panther had a flaw also related with driver's hatch; if shell ricocheted from the turret, it could have just 'dropped' down just above driver's hatch -> drop through it to the driver's head and actually might kill him or incapacitate him.

 

[[TW]Wilsonam]

So i'm assuming that the general assumption that German armour quality deteriorated towards the end of the war is correct.

You have to be careful with jumping to generalisations There are a number of reports in the archives about problems with German armour steel quality - but it only seems to be in certain instances - one example being the Panther for a period of time. The "general" quality didn't deteriorate - another possible reason mooted for them using thicker and thicker armour is that it required lower hardness and they could make that more easily with what they had available.

Anyway - yes, there was certainly a batch of Panthers with "poor quality" armour, heavily prone to shattering and, presumably, flaking/discing on the back face.

Do we model this in game? No. But it is all a part of "future research"

 

[Recce]

What apears to be a chin on the mantle suggests a Panther G.

Sorry mate, but that's not a "chinned" mantlet, it's just some debris on the roof.
As you can see below, the "chinned" mantlet does not extend (significantly) lower than of the earlier design. Rather the lower edge has been "built up" to removed the curve.

 

[wokelly]

Ah, thanks for pointing that out about the chin mantle.

You have to be careful with jumping to generalisations There are a number of reports in the archives about problems with German armour steel quality - but it only seems to be in certain instances - one example being the Panther for a period of time. The "general" quality didn't deteriorate - another possible reason mooted for them using thicker and thicker armour is that it required lower hardness and they could make that more easily with what they had available.

Anyway - yes, there was certainly a batch of Panthers with "poor quality" armour, heavily prone to shattering and, presumably, flaking/discing on the back face.

Do we model this in game? No. But it is all a part of "future research"

Actually armor quality for all german armor would have decreased. The move from Molybdenum to Vanadium was not just in panthers, it was in all tanks from the Mark 4s to the King Tigers. The panther just happened to be the focus of this article because of the debate of Panther Armor Quality on WWIIOL forum, but it would have affected all tanks because vanadium armor was not as good as the armor it was replacing.

 

[Desy19]

You guys are great! So much useful information. I am very glad that I joined you!

feedback4oldnavy