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"Sherman armor vs Tiger armor?" Topic


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1,204 hits since 2 Apr 2017
©1994-2017 Bill Armintrout
Comments or corrections?

RetroBoom Inactive Member03 Apr 2017 9:35 a.m. PST

Tiger I's frontal armor is 100mm thick and almost flat. The M4 Sherman had half the armor thickness… however the frontal armor is sloped 56.

In theory, the Sherman's frontal slope should effectively double it's armor thickness, matching the tiger's front armor.

This certainly isn't the common attitude though, looking at wargame anyway. Any one looked into this before? Have any thoughts?

Thanks! :D

Mako11 Inactive Member03 Apr 2017 9:40 a.m. PST

Actually, that's from the horizontal plane, I think, so the real, effective sloping is about 34 degrees, which helps a little, but doesn't double the armor like being at 60 degrees does.

Garand03 Apr 2017 9:44 a.m. PST

I just punched the numbers into an Armor calculator link & the results I got was that the Sherman's relative armor thickness is more like 60mm. Even if I botched the angle modifier (the 60mm is from the horisontal), if you put it at 56deg from the vertical it still only comes out to approx 89.5mm. So still deficient compared to the 100mm of the Tiger. Also one tactic crews would sometimes do is park the tank at an angle from the enemy, so that they can still get the benefit of a slope, just at a different angle.

Damon.

Personal logo herkybird Supporting Member of TMP03 Apr 2017 9:52 a.m. PST

I think German anti tank rounds were capable of knocking a hole in a Sherman front armour whatever angle it was, at least after the introduction of the PaK 38 L60!

Vintage Wargaming Supporting Member of TMP03 Apr 2017 9:53 a.m. PST

Then you need to factor in the respective AP capabilities of the Tiger's 88mm and the Sherman's 75mm if you are matching the two up

Mark 1 Supporting Member of TMP03 Apr 2017 10:08 a.m. PST

The metallurgy was different, so just counting the thickness in mm and using a slope multiplier does not get us to the right result.

US armor was relatively soft and ductile. BHN was about 220 240. It seems that Ordnance was almost as concerned about the after armor effects of penetration as they were on preventing penetration. The softness and ductility meant that the armor didn't shatter, and very little armor splash carried into the fighting compartment when the armor was penetrated. To some extent this could be considered a proven benefit, as US tank crew casualties were probably the lowest, per tank KO'd, of any nation in WW2. However, many factors contribute to survivability (not just behind-armor splash), and most tankers prefer to think of the armor as being there to keep things out, rather than to let them in with minimal fuss.

The ductility also improved the machinability of the plate, easing manufacturing. This no doubt contributed to the preference for this plate as well.

Tiger's armor metallurgy was the best and most expensive among the German tanks. Notably high in both hardness and tensile strength. It contained a high nickel component, which made it quite expensive and also progressively more difficult to obtain in time, and also made it complicated to machine and weld during the manufacturing process.

US Army Ordnance testing showed that the US 3-inch and 76mm guns could easily handle Tiger levels of armor. They were wrong. They tested on US test plate, which did not show them the resistance of Tiger's armor. This is a little appreciated part of the 1944 US guns vs. German armor problem … somewhat similar to the USN torpedo testing in 1941/42, US AP rounds simply didn't deliver, in combat, what Ordnance expected them to deliver based on test results.

Later German tanks (Panther, Tiger II) moved to more conventional armor compositions and used sloping or greater thicknesses to enhance their protection, but Tiger really got the most out of the protection that could be managed in a 56 ton vehicle.

Or so I've read.

-Mark
(aka: Mk 1)

Personal logo Weasel Supporting Member of TMP03 Apr 2017 10:10 a.m. PST

I suppose not relevant for the Tiger I, but didn't German armour manufacturing slip considerably late-war, leading to brittle-ness?

RetroBoom Inactive Member03 Apr 2017 10:34 a.m. PST

Thanks, guys, for the info! Interesting stuff.

surdu2005 Sponsoring Member of TMP03 Apr 2017 10:39 a.m. PST

The Sherman is a medium tank. The Tiger is a heavy tank.

Skarper03 Apr 2017 11:17 a.m. PST

ASL has the better armoured Shermans with an 11 armour factor [supposed to be 11cm]. The same as the Tiger 1's Hull front. [Glacis?]

I like the Panzer War tables which have 10 locations for each facing, bringing in some subtle variations.

The main problem is the tanks guns. Even the US 76mm was marginally effective vs the Tiger while the German 75s and 88s [even the PzIVs 75mm L48] could comfortably defeat Sherman Armour.

This is the main reason Shermans burned a lot and German tanks did not so much. Nothing to do with the diesel/petrol thing. Or so I read somewhere.

Who asked this joker03 Apr 2017 11:22 a.m. PST

There was a video on youtube with a tank historian who debunked the weak armor of the Sherman. From the front, the Sherman has about 2.36" of armor on the hull. With the slope factored in, it had an effective armor thickness of something like 3.92". The turret front has a bit more with around 3" of armor but a shallower slope. So long as you can keep the front facing toward the enemy, you stand a chance to survive.

I suspect most of the Sherman losses occurred when they were stuck in the side, where the armor was not nearly as effective.

This video here. YouTube link 1 hour long but well worth it.

I suppose not relevant for the Tiger I, but didn't German armour manufacturing slip considerably late-war, leading to brittle-ness?

By mid-war, the Germans were suffering from an accute shortage of nickel which would make it more difficult to make a quality hard steel. The ME-262 engines, for instance, had to be warmed up gradually or they would seize up all because the Germans could not make properly hardened steel.

Mark 1 Supporting Member of TMP03 Apr 2017 11:27 a.m. PST

I suppose not relevant for the Tiger I, but didn't German armour manufacturing slip considerably late-war, leading to brittle-ness?

Nickel, chromium and molybdenum became progressively more scarce due to the effective blockading of outside sources.

The German steel industry was pretty sophisticated. So as various metals became scarce, the metallurgy changed to allow production to continue without the missing components.

How much brittleness was introduced to German tank armor production is a reasonably contentious question. Most of the wartime firing tests were done on limited samples of captured German tanks. The tanks captured intact were often put to use in the front lines (at least on the Eastern front).

Those expended on firing tests were often the tanks that were not considered as runners … the combat losses vs. the depot-captures. If the tank had burned in combat the characteristics of the armor could change from the heat. Test captures were usually fired at many times. The typical testing profile was limit testing (find the range / velocity at which it fails to penetrate) on each of several guns. Plates which are struck many times, and penetrated multiple times, will often start to demonstrate failures due to un-seen cracking within the metal.

Put these together, and a reduction in ductility (due to changing metallurgy) can be amplified by the testing regimen.

Also there is some evidence to suggest poor manufacturing quality control in some production lots. This is particularly the case in Panther production. With a very small sample set to test fire against, a small variance in quality control can be amplified to a larger (and un-warranted) inference across the board.

But all of that said, both on the Eastern Front and in the west there were test results suggesting a decline in armor quality, or at least a decline in quality control.

Following is the best description I have seen of the changing metallurgy and later war quality flaws in German armor, with primary sources provided for those interested in further study. From a tanknet discussion in 2007:


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 (always a non-burner or flamer as this affects the testing), and in the case of the US was shipped to Watertown Arsenal or other US testing facilities.

For those interested in this question you can use the DTIC document library to order the various testing reports. If you want Tiger info try WAL 710/542 – Armor and Welding on a Pz VI Tiger Tank…for example…or WAL 710/608 – Armor and welding on a Pz-IV etc. All these documents are now public domain, and thus its easy to follow the metallurgical trail so to speak.

Over the course of 1944, with most fingers pointing to early in same, the Germans changed the alloy composition of their armor. Prior to this time the usual Cr-Mo 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. Mo was dropped and the plates started their trend to .5% carbon, 2% Chromium, and .14% Vanadium composition. Obviously Mo was running short or had disappeared, and a substitute had to be found that was generally acceptable…and that 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 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 you see large tears in a plate with considerably more material/spall forced into the AFV.

Another issue with this composition is quench cracking…if you dont quench the plate properly in manufacturing you can generate cracks that are inside the plate and invisible to the naked eye. Armor with interior cracking or non-uniform composition is obviously a bad thing when you hit it with a high velocity projectile.

Then, and this is especially true of plates greater than 2" in thickness, the same mad rush to satisfy quantity (thus screwing up your quench cycle) can also affect the quality of the plate. In case of a vandium based steel, you will use less alloy to make it for a given weight, but between that and improper quenching you end up with steel of inferior hardness.

Finally we top all that off with improper tempering…and you actually induce brittleness into what is already a faulty plate. The faulty tempering occured 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 you want 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.

The Panther glacis armor sampled in 1944 demonstrated all these characteristics, and more. Its not that the design of the plate or the weld was bad, it was simply that 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 shouldnt 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. I'm sure 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.

Other nations had their issues as well…early war matildas for one had issues with castings with regards to both metallurgy and process control early on. These were often a function of a single manufacturer and the controls in place at that location.

So – there you have it. The reduction in armor quality was a product of nothing more than facts. A lack of appropriate alloys and a lack of attention in materials manufacturing…all of which made for brittle and shatter prone tanks and welds.

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.

… Anyone interested in a late war panther sampling can order ADA 954940 or 954952 for ord. dept comments as well as the full metallurgical workups of a typical late model panther. … Let the spectroscopy and microscopes in the reports do the speaking…
- 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.

In this case, opposite to the criticism of US Army Ordnance, I would be more convinced by the metallurgical analysis than by test firing. Test firing against a few captured tanks can very credibly tell you that your round does not penetrate. It can not credibly tell you that your rounds DO penetrate … for that you need a combination of theory and practice, of the metallurgy and in-house testing with field tests against the actual enemy tanks.

-Mark
(aka: Mk 1)

BattlerBritain03 Apr 2017 1:41 p.m. PST

Great references Mark1.

Mobius03 Apr 2017 2:01 p.m. PST

Tiger I's frontal armor is 100mm thick and almost flat. The M4 Sherman had half the armor thickness… however the frontal armor is sloped 56.
Well, you are right for the early type of Sherman. The glacis armor was cast 2" thick though. Plus the hatch cut-outs which were less than 56, The later Shermans had 2.5" rolled armor at 47. The equivalent armor basis was about the same.
The lower hull was also different. Early had 2" curved 3 pieces bolted together.

Ragbones Supporting Member of TMP03 Apr 2017 5:34 p.m. PST

Mark, that was some very interesting information! Thanks for posting.

Rich Bliss Supporting Member of TMP03 Apr 2017 5:55 p.m. PST

Good stuff indeed. The higher carbon levels are obviously an attempt to increase strength but resulted in a loss of ductility.

Blutarski03 Apr 2017 6:36 p.m. PST

Under ideal conditions of manufacturing, cast steel armor has a protective value approximately 0.85 that of an equivalent thickness of good quality rolled homogeneous plate. Unfortunately, US industrial capability with respect to manufacture of large armor castings such as the Sherman hull and turret was far from ideal. The US Army's commitment to cast armor for reasons of more rapid production resulted in the cast hull Shermans (which constituted the majority of Shermans produced) a good deal less well protected than even their modest nominal armor statistics suggested.

Go here for reference (worth reading) –
link

B

Personal logo Weasel Supporting Member of TMP04 Apr 2017 4:45 a.m. PST

Mark is a scholar and a gentleman.

Tachikoma04 Apr 2017 5:16 a.m. PST

There were approximately 10,000 cast hull (or partially cast hull) Shermans produced out of a total production run of around 49,000, hardly what I would call a "majority". The Army's plan to increase tank production and reduce bottlenecks centered around concurrent production of various models with different engines and both cast and welded hulls.

christot04 Apr 2017 7:22 a.m. PST

Great stuff…and a good example of why rules with incredible minute detail on armour stats are wasting their time

jah1956 Inactive Member04 Apr 2017 7:41 a.m. PST

christot well said

Mobius04 Apr 2017 8:29 a.m. PST

Under ideal conditions of manufacturing, cast steel armor has a protective value approximately 0.85 that of an equivalent thickness of good quality rolled homogeneous plate.

Close. 50-75mm cast armor is equivalent to 80-85% of RHA. 75-100mm cast armor is closer to 90% of RHA and 120mm cast is like 95% of RHA. In some tests the US 47 63.5mm RHA armor resisted like 90-93mm cast armor.

In post war Yugoslav tests the Sherman softer armor resisted 50-76mm AP German, Soviet and US shells almost exactly like the hardened T-34/85 armor.

Skarper04 Apr 2017 9:20 a.m. PST

My feeling on detailed rules for armour values is – fine, good to have the data but don't think that's the end of the story.

You might as well start from an accurate piece of data [as far as that is even possible] but then you have to factor in a good deal of randomness.

I've played rules with utterly arbitrary data based on no research at all and they just threw up out of whack results.

christot04 Apr 2017 10:21 a.m. PST

Exactly, as long as the rules (stats) throw up the right "feel" then you are golden, fussing over whether the relative side armour of X vehicle should be 22 or 24 out of a range of 200 at a deflection of $ degrees is utterly, utterly futile to the point of Onanism

Ivan DBA04 Apr 2017 8:01 p.m. PST

I don't care what some so-called expert "proved" on a napkin with high-school trigonometry. Oddball said there's only one place you can take out a Tiger, and that's its a…!

Blutarski04 Apr 2017 8:04 p.m. PST

Re cast versus welded hull Shermans in the US Army, see Wikipaedia

"During World War II, approximately 19,247 Shermans were issued to the US Army …"

"The M4 (note 1) and M4A1 note 2) were the main types in U.S. units until late 1944, …"
Note 1 early M4s welded hull; later M4s composite cast front and welded side armor.
Note 2 M4A1s all cast hull.

If you take 9707 cast hull M4A1s + approx 4000 composite hull M4s, then somewhere around two-thirds of US Army Shermans were cast hull or composite cast hull.

The first M4A3s (welded hull) did not start to reach the ETO until approx Aug 1944.

The majority of welded hull M4A2s and M4A4s went to US allies under Lend-Lease.

B

Thomas Thomas Supporting Member of TMP05 Apr 2017 8:28 a.m. PST

For wargames purposes here's the quick and dirty:

Slope 60 degrees X2; 30 degrees X1.5 thickness.

Panther quality: make Panther/Tiger I about the same (while Panther nominally better shot trap/quality evens out). Panther weaker on side (about same as M4) and aganist indirect fire.

M4's still a cut below despite well sloped hull, so:

Tiger/8.8L: Heavy(-) & PzV/7.5XL: {Heavy(-)} ("{}" = weak side armor)

M4/7.5N & T34/7.6N: Medium(+)

For more get Combat Command….

Thomas J. Thomas
Fame and Glory Games

Marc33594 Supporting Member of TMP05 Apr 2017 1:19 p.m. PST

Only a total of 6,281 M4A1's were produced, not sure where you are getting 9,707 from. Of those 2,932 M4A1s were issued to US Army units overseas and not just European theater.

As to the M4 6,748 were produced including the composite hull examples. Of that number some 3,573 were issued to US forces overseas, once again not just Europe. Production numbers for the composite Sherman vary. Most accept approximately 50 on the small hatch M4 and 1,418 on the large hatch for a total of 1,468. Another source I have seen says a total of 1,676. If we figure shipments overseas was proportionate then even at the larger number we are talking about some 900 were shipped overseas to US Army forces. But even if the entire production was shipped and even if we use the larger number produced still well short of the 4,000 you are claiming.

Sources:
Sherman: A History of the American Medium Tank by R.P. Hunnicutt
Armored Thunderbolt: The U.S. Army Sherman in World War II by Steven Zaloga
The Sherman Design and Development: A complete and illustrated description of the U.S. Sherman tank series in the Second World War, Volume 1 by Patrick Stansell and Kurt Laughlin

Marc33594 Supporting Member of TMP06 Apr 2017 6:38 a.m. PST

My apologies to Mr Blutarski. If you include the 76mm M4A1, which you should, the production figure is correct. Still I believe you will find that approximately 1/3 of all Sherman gun tanks (75 and 76) issued to US forces overseas were either cast or composite hull, not the two thirds cited. I have also excluded production of the 105mm armed tanks.

Blutarski18 Apr 2017 2:12 p.m. PST

Marc33594 wrote "I believe you will find that approximately 1/3 of all Sherman gun tanks (75 and 76) issued to US forces overseas were either cast or composite hull, not the two thirds cited. I have also excluded production of the 105mm armed tanks."

Marc,
I did some further investigation and thinking about numbers of cast versus welded Shermans that saw service in the ETO. A review of book illustrations and several large web photo archives (where cast Shermans were noteworthy by their rarity in photographs) have led me to re-think my position. I believe that you are in fact correct. The simple production figures do not tell the entire story. The M4A1 cast M4s, produced in large numbers in 1942-1943 had obviously been committed to the N African, Tunisian and Italian theaters well before Normandy.

Thanks for politely provoking me to re-consider this point.

B

Marc33594 Supporting Member of TMP19 Apr 2017 3:04 p.m. PST

I believe you were first by not noting my error in adding the numbers :)

And the best of threads. Everyone civil, an enjoyable conversation and I learned something as well!

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