BF-109 Metallurgical Quality?

[ThomasP]

Hey pbehn,

Although grain size would vary a bit from mid-plate to surface, there was probably not as much variation as you may be thinking. The process used to make homogeneous plate almost always involves the hot rolling method, which is effectively a form of forging. Some armour plate was cross rolled, ie 2 rolling directions at right angles to each other. Assuming good quality control, the alloys used and the hot rolling process tends to generate relatively similar grain size through the entire thickness, providing similar mechanical properties through the entire thickness (hence the name homogeneous).

All of the major combatants had specifications for their versions of face hardened and homogeneous plate. At one point in time I had the armour specification data for all the major combatants (except the Soviets) on my computer, but that computer's motherboard failed about a 9 months ago. I have not yet recovered the data due to the uniquely (ie stupidly) propriety (Apple) software/hardware controlled solid state storage device (that is apparently not a normal SSD and was only in production for about 6 months during the second half of 2009). And I did not constantly back it up as I should have.

For the UK series used on their armoured vehicles, although it is incomplete, I still have this for Rolled Homogeneous and Cast Homogeneous armour Brinell values:

The US, Germany, Japan, and Italy had similar ranges, although IIRC the German specifications changed more drastically as the war progressed. There were similar specifications for Face Hardened plate, with the face hardness, depth of hardening, and hardness of the softer backing material all specified in a similar manner to the above chart. In addition, everyone had specifications for full-hardness plate (ie hardened all the way through) for a range of thinner plate. There are also other values used in the specifications such as acceptable grain sizes, grain orientation, ductility, tensile/shear strengths, etc.

Although I am not familiar with the Soviet standards in any detail, my understanding from various technical publications is that they were similar to those of the US/UK/Japan/Germany/Italy.

As far as temperature goes, I assume you mean relative to the ambient air temperature when the damage occurred? If so then no, there would be no significant effect. While extreme cold can effect the mechanical qualities of metals, the phenomenon of steel becoming brittle at low temperature that we usually hear about involves much lower temperatures than what was occurring in Europe during WWII. Although I should note that a one time effect on high quality armour plate (such as impact of an AP projectile or blast of a large HE explosion) will not be aggravated by the cold as much as a constant working of low quality (possibly sub-standard?) plate (such as may occur in the hull of a ship at sea).

 

[Deleted member 68059]

Marseille and other pilots were not lost because of metallurgical issues but due to an oil foaming problem which interrupted the oil flow in the engines which then led to them blowing up.

Your archive references being ____________ ?

Mine are Milch microfilm of RLM stenographic records in Berlin, Volume 16, Frame 2624... October 6th, 1942.
Available from the Imperial War Museum, London.

 

[pbehn]

Isnt oil foaming often a symptom of a mechanical failure?

 

[pbehn]

Hey pbehn,

Although grain size would vary a bit from mid-plate to surface, there was probably not as much variation as you may be thinking. The process used to make homogeneous plate almost always involves the hot rolling method, which is effectively a form of forging. Some armour plate was cross rolled, ie 2 rolling directions at right angles to each other. Assuming good quality control, the alloys used and the hot rolling process tends to generate relatively similar grain size through the entire thickness, providing similar mechanical properties through the entire thickness (hence the name homogeneous).

All of the major combatants had specifications for their versions of face hardened and homogeneous plate. At one point in time I had the armour specification data for all the major combatants (except the Soviets) on my computer, but that computer's motherboard failed about a 9 months ago. I have not yet recovered the data due to the uniquely (ie stupidly) propriety (Apple) software/hardware controlled solid state storage device (that is apparently not a normal SSD and was only in production for about 6 months during the second half of 2009). And I did not constantly back it up as I should have.

For the UK series used on their armoured vehicles, although it is incomplete, I still have this for Rolled Homogeneous and Cast Homogeneous armour Brinell values:

View attachment 590064

The US, Germany, Japan, and Italy had similar ranges, although IIRC the German specifications changed more drastically as the war progressed. There were similar specifications for Face Hardened plate, with the face hardness, depth of hardening, and hardness of the softer backing material all specified in a similar manner to the above chart. In addition, everyone had specifications for full-hardness plate (ie hardened all the way through) for a range of thinner plate. There are also other values used in the specifications such as acceptable grain sizes, grain orientation, ductility, tensile/shear strengths, etc.

Although I am not familiar with the Soviet standards in any detail, my understanding from various technical publications is that they were similar to those of the US/UK/Japan/Germany/Italy.

As far as temperature goes, I assume you mean relative to the ambient air temperature when the damage occurred? If so then no, there would be no significant effect. While extreme cold can effect the mechanical qualities of metals, the phenomenon of steel becoming brittle at low temperature that we usually hear about involves much lower temperatures than what was occurring in Europe during WWII. Although I should note that a one time effect on high quality armour plate (such as impact of an AP projectile or blast of a large HE explosion) will not be aggravated by the cold as much as a constant working of low quality (possibly sub-standard?) plate (such as may occur in the hull of a ship at sea).

Thanks. for my sins I spent far too much of my life watching plates being rolled, made into pipes and tested. Fortunately, or unfortunately it was at some of the worlds most advanced plate mills. Even in 1986 when I was at NKK in Fukuyama (now JFE) they were using advanced controlled rolling and accelerated cooling techniques so an X65 plate with hardness of 220VPH and Charpy of 500J was normal. I was interested in the report on tank armour in so far as how much would be done differently today, there would be a transition curve for Charpys and much more hardness testing with Vickers. It occurred to me from the report that the Germans were not only short of alloying elements but also of fuel and also of tanks, heat treatment uses huge amounts of energy how ever you do it. They may have made a decision to produce more tanks at lower quality. I asked about temperature because while captured tanks falling into UK/US hands were probably from Europe or Africa but photos could be from anywhere and tanks were used on the eastern front at very low temperatures easily into the transition temperature of that type of steel.

 

[NevadaK]

Interestingly, I came across this study a couple weeks back and forgot to post it on another thread. This should answer your question:

Comparison of Aluminum Alloys from Aircraft of Four Nations Involved in the WWII Conflict Using Multiscale Analyses and Archival Study

 

[Juha3]

Hey pbehn,

...For the UK series used on their armoured vehicles, although it is incomplete, I still have this for Rolled Homogeneous and Cast Homogeneous armour Brinell values:

View attachment 590064

...

So Your source seems to be Bird and Livingston, World War II Ballistics: Armor and Gunnery, Overmatch Press 2001 page 8

 

[pbehn]

Interestingly, I came across this study a couple weeks back and forgot to post it on another thread. This should answer your question:

Comparison of Aluminum Alloys from Aircraft of Four Nations Involved in the WWII Conflict Using Multiscale Analyses and Archival Study

In terms of the OP one of the conclusions is interesting "Taking the chemical composition into consideration and the History, two trends were observed: Germany, France, and the USA versus UK. The first three nations followed Alfred Wilm's patent, while the United Kingdom developed its own slightly different versions of duralumin."

Alfred Wilm - Wikipedia

Alfred Wilm (25 June 1869 – 6 August 1937) was a German metallurgist who invented the alloy Al-3.5–5.5%Cu-Mg-Mn, now known as Duralumin which is used extensively in aircraft.[1]
Whilst working in military research NUTZ in Neubabelsberg in 1901, Wilm discovered age hardening, in particular age hardening of aluminium alloys.[2] This discovery was made after hardness measurements on Al-Cu alloy specimens were serendipitously found to increase in hardness at room temperature. This increase in hardness was identified after his measurements were interrupted by a weekend, and when they were resumed on the Monday the hardness had increased.[3]
By 1906, Wilm had developed an alloy – Al-3.5–5.5%Cu-Mg-Mn, Mg and Mn were < 1%, for which a patent was filed.[4] Later this patent was purchased and the alloy marketed as Duralumin. Somewhat unusually, Wilm did not write his first article on age hardening until 1911.[2][5] At the time Wilm was developing an aluminium alloy to replace brass in ammunition. The patent on Duralumin was ignored and breached by many firms, and he struggled without success to protect his rights under it.
In 1919 Wilm retired from research and became a farmer. He died at his farm in Saalberg on 6 August 1937.

 

[ThomasP]

Hey Juha3,

re:"So Your source seems to be Bird and Livingston, World War II Ballistics: Armor and Gunnery, Overmatch Press 2001 page 8"

That may be where this particular table came from, I do not know. I found it online a few months ago on another forum. It uses the same/similar values as were reported in various wartime and post-wartime documents. There are many official military reports/studies, and less official write-ups, that can be found online. I remember finding the listed values above, and similar ones for the US, in official military reports. But I have not taken the time to re-find them on the internet since my computer crapped out. There are also various industry technical studies that report on the different types of alloy plate and their methods of forming, including their compositions and quality control specifications. Again most of what I had was on the old computer.

 

[ThomasP]

Hey pbehn

re:"I asked about temperature because while captured tanks falling into UK/US hands were probably from Europe or Africa but photos could be from anywhere and tanks were used on the eastern front at very low temperatures easily into the transition temperature of that type of steel."

It would be difficult (maybe impractical) to look at and compare the behavior of any significant number of the armour types used in WWII by the combatants, within a forum setting. It usually takes at least a pamphlet or small booklet at a minimum.

However, if the quality control was good, most(all?) of the types of armour with significant amounts of nickel (3%-10%) used during WWII would have been quite resistant to the effects of cold, and in some cases the mechanical properties would have improved with lower temperatures.

This graph gives an example of the temperature effects vs 9% nickel (about the maximum used in any WWII armour?) low carbon steel.

As you can see, the BHN increases by about 10% and tensile strength by about 11% as the temperature drops from +75°F to -50°F, while the yield strength only drops about 3% and the elongation (ductility) drops about 2% over the same temperature range.

I do not have an uploadable image of the chart for low alloy ship plate (typical hull plating used for commercial ships in the WWII and immediate post-war era), but within the range of +75°F to -50°F, the BHN and tensile strength will increase about 10% while the elongation/ductility will decrease about 10%.

I have a copy of the "Mechanical Properties of Structural Materials at Low Temperatures", 1960, National Bureau of Standards Monograph 13, which provides charts for many materials, ferrous and non-ferrous. If there is a copy online somewhere anyone interested in this type of thing should look it up.

 

[ThomasP]

Found it on the dtic site.

"https://apps.dtic.mil/dtic/tr/fulltext/u2/a041093.pdf"

 

[MiTasol]

I would suggest a web search for the USSBS (US Strategic Bombing Survey) files on German airframe metals. I am fairly sure that there will be one or more on the subject

 

[MIflyer]

I recall reading in more than one publication that German aircraft used an AL alloy that used a high precentage of Magnesium. Whether this was a feature of Strength/Weight design or a response to material shortages I do not know. But one of the results was that when German aircraft caught fire the airframe ignited in addition to the normal combustibles. RAF night fighter crews reported that the a burning German aircraft produced a unique sickly smell. And other source said that when burning BF-109 bellied in on the sand of the Western Desert in N Africa, there was sometimes little left but pools of melted aluminum, the magnesium being consumed by the fire.

The Me-262 used a high percentage of steel in its airframe, apparently due to shortages.

 

[MiTasol]

5000 series alloys are and were common in all countries, and they can be welded unlike high strength alloys, but I would strongly doubt they would be used much in structure as the volume you would need to use to compensate for their lower strength would make a very heavy aircraft.

 

[manta22]

The quality of almost everything suffered as the war progressed. Shortages and the need to speed up production inevitibly reduced the quality of manufactured items. As an example, look at the production history of the Polish VIS 35 pistol. Produced by the Poles before the war, it was a fine high quality firearm but when the Germans captured the factory, its fit & finish quality slowly degraded. Production demands later necessitated the elimination of features such as the grip safety, takedown notch, and the overall quality became abysmal. In addition there were thefts of parts from the factory that became such a problem that final assembly of the pistols was shifted ro Steyer in Austria.

 

[brianwnz]

A short translation from a German aircraft diesel engine report, written by one of the engineers involved many years afterwards:

"Even before and especially at the beginning of the Second World War, the difficulties of obtaining materials increased according to the German armaments projects. Subcontractors such as the light metal foundries no longer had free capacity available. Alloy materials such as copper, cobalt and, above all, nickel became extremely scarce and required approval by the responsible Wehrmacht agencies, which relied on priority programs. The situation was even worse in terms of personnel, as more and more personnel were called to arms over time....."

- Please excuse my translation; it is via Google!.......

 

[NevadaK]

The report I posted earlier in this thread showed that the US used allows with higher percentages of magnesium that Germany, the UK and France.

 

[fastmongrel]

The most advanced non ferrous aircraft alloys seem to have been Japanese.

 

[Denniss]

Your archive references being ____________ ?

Mine are Milch microfilm of RLM stenographic records in Berlin, Volume 16, Frame 2624... October 6th, 1942.
Available from the Imperial War Museum, London.

You seem to misinterpret your sources. It's well known that the DB 605A had a massive problem with foaming oil leading to many failed, blown or bursting-into-flames engines. As this mostly happened under maximum load the engine max power was restricted until the engine was rebuilt to fix the problem. I can't remember to have read of similar problems with later DB 601 types.
Early Bf 109F were affected by structural failures of the wing or the rear section, the latter cuased by harmonic vibrations with the engine at certain engine power settings. This did cost the lives of multiple pilots when a wing or tailplane separated in-flight.
Marseille's death was caused by a bursted and burning DB 605A of his Bf 109G-2 trop

 

[Deleted member 68059]

You seem to misinterpret your sources.

Lets have a forum poll about that one shall we?

 

[Mad Dog]

It was a really serious buisiness, and did for Hans-Joachim Marsellie as well as many other top pilots.

The problem with the stories/myths around the deaths of many Luftwaffe experten is that they were written (or at least polished) by Goebbels's propagandists. Try finding one example of an official account of an experten's demise where they admit he did something stupid or made a mistake, and you will find it a fruitless endeavour. This problem is exacerbated by the post-War indulgence of Western experts that rushed to pronounce the experten as next to godly, despite them having been soundly thrashed by the Allies.