Jumo 004

[2gvshad_alaska]

Excuse me for my bad English.

I have access to several engines period WW2, and I can do pictures and measurements of the components

[psteel]

Hi guys. I'm wondering if you can help me with quesitons about the Jumo 004 engine.

It says in this article ....

http://www.enginehistory.org/German/...2_Engine_2.pdf

That the Turbine blades were 'stamped aluminum', then 'mild steel coated in enamel coating', then later solid 'Austentic steels' , but also it reports that 'hard chrome solid steels blades' where used. It also states that the amount of solid steel blades seemed to increase as the war progressed.

The Diagram lists "17 Swg Cr. Mn. steel " for the hollow blade. The best translation I can get is some heavy/hard Chrome Magneseum Steel??? Above that diagram , it seems to report the original 004A engine used solid blades.

I wonder if the "17 Swg Cr. Mn. steel " alloy is also this 'hard chrome solid steels blades' ? I wonder if 17 refers to 17% Cr?

Also the begining article referes to some end of war alloy that allowed 500 hours bench test and 150 hours operational usage. Since their are a million articles on this the operational life is reported at 10 hours 12 hours, 25 hours , 50 hours for the B models and 200-250 hours for the A model and the above mentioned 150 hours at the end of the war . Could that refer to the Jumo-004D model that supposedly entered production at the end of the war or the Jumo 004E that was due to enter production in the summer of 1945??

Could the increasing engine life reported be related to the movement to stronger and stronger turbine blades ?

Is the Tinidur alloy really be 30% Nickel and 14% Chrome because thats a hell of a lot of such alloys for a cheap alternative to extensive Chrome Nickel steels?

Dr. Anselm Franz initially used an improved version of P-193 known as Tinidur – austinitic 'stainless steel' like steel alloy with 6% titanium, 18% nickel 12% chromium with the balance of steel.

I've seen some sources say the switch to the B model reduced the about of Chrome used by a factor of 3 and that 21 lb of Chrome was used in the Jumo 004A while the Jumo 004B had only 7 lbs or 2.3kg. If 21 lbs is 14%, then the turbine blades only amounted to 150 lbs which does jive with the weight figures given in the article but only if that refers to the Jumo 004A model. If the 7 lbs refers to the model in the article then the turbine blades only amount to 50 lbs and the weight saving must be on the order of 100lbs or 45kg?

This article suggests a different alloy? They are refering to a range of very strong aluminum turbine blades?

Messerschmitt Me 262. [Archive] - WW2 in Color History Forum

Usually High temperature stainless steel alloys [austentic steel] are 4-6% chrome and small amounts of Mo, Si , C, Mn, & Ni....any one have any info on this mysterious alloy the Germans had at the end of the war that solved the engine reliablity problems and was mass producable given their impossible special alloy situation?


Don't worry if your confused, because your not the only one

[jerryw]

Here are some of the answers to questions posed by psteel regarding the Junkers 004 turbojet.

1/ The references in the John Foster article posted on the enginehistory website to blades of "stamped aluminium" and "sheet steel, zinc coated" refer to COMPRESSOR blades, not turbine buckets. I think you have mis-read the article at this point. Turbine blades would never be made of aluminium as its melting point is too low.

2/ The reference on the drawing to "17 SWG Cr Mn steel". "17 SWG" is a DIMENSION, not a type of steel.
"SWG" means, "Steel Wire Gauge". There are many different scales of wire gauges used in industry; in this case 17 SWG means a diameter (or thickness) of 0.045 inches, ie just over 1 mm. (16 SWG is 0.050 ins, 19 SWG is 0.035 ins and so on.) This means the walls of the hollow turbine blades are 45 thou thick.
"Cr Mn steel" refers to an alloy of Chromium and MANGANESE, not Magnesium. The symbol for magnesium is Mg.
The Cr/Mn alloy being refered to here is CROMADUR which contained 12% Cr and 18% Mn as principal ingredients. No Nickel in this alloy so it is not an AUSTENITIC steel type.

3/ The TINIDUR alloy did contain 30% Nickel and 14% Chromium, ie it was an austenitic steel which, as you say, is "a hell of a lot"! and that is why the Germans switched to Cromadur to cut the requirement for Nickel.

Hope that helps with your understanding of turbojet development.

[psteel]

Originally Posted by jerryw

Here are some of the answers to questions posed by psteel regarding the Junkers 004 turbojet.

1/ The references in the John Foster article posted on the enginehistory website to blades of "stamped aluminium" and "sheet steel, zinc coated" refer to COMPRESSOR blades, not turbine buckets. I think you have mis-read the article at this point. Turbine blades would never be made of aluminium as its melting point is too low.

2/ The reference on the drawing to "17 SWG Cr Mn steel". "17 SWG" is a DIMENSION, not a type of steel.
"SWG" means, "Steel Wire Gauge". There are many different scales of wire gauges used in industry; in this case 17 SWG means a diameter (or thickness) of 0.045 inches, ie just over 1 mm. (16 SWG is 0.050 ins, 19 SWG is 0.035 ins and so on.) This means the walls of the hollow turbine blades are 45 thou thick.
"Cr Mn steel" refers to an alloy of Chromium and MANGANESE, not Magnesium. The symbol for magnesium is Mg.
The Cr/Mn alloy being refered to here is CROMADUR which contained 12% Cr and 18% Mn as principal ingredients. No Nickel in this alloy so it is not an AUSTENITIC steel type.

3/ The TINIDUR alloy did contain 30% Nickel and 14% Chromium, ie it was an austenitic steel which, as you say, is "a hell of a lot"! and that is why the Germans switched to Cromadur to cut the requirement for Nickel.

Hope that helps with your understanding of turbojet development.

Thanks Jerry and it does help to clarify somewhat. I did wonder how on earth Aluminum could be used when the article reports temperatures in the 400-700°C region.

I have read some articles that refer to the Tinidur as the cheaper alloy that was used in the Jumo -004B that made it possible. But what you are saying is this would have been in the Jumo 004A model, while the "Cromadur alloy" would have been the hollow alloy blades in the Jumo 004B. One confusing point is that allot of articles reference the amount of Chrome used [21 lbs vs 7 lbs] , but it would seem the nickel situation would be the rate determining step.

Now all I need to find out is what this mysterious alloy referred to in the start of the other article focusing on the Jumo-004, that allowed the 150 hours operational usage. Any clues?

[veloracer]

The excerpt below may answer some of your material questions:

"In 1936, when development work on the Jumo 004 started, a high-temperature Krupp steel known as P-193 was available. This material, which contained Ni, Cr, and Ti, could be given good high-temperature strength by means of solution treating and precipitation hardening. Krupp developed an improved version of P-193 known as Tinidur. It was of the same type as Nimonic 80, which was used in British Gas turbines from 1942 but contained over 50 percent iron (which was replaced by Ni in Nimonic 80) and this caused a rapid drop in creep strength at 1080F (compared to 1260F for Nimonic 80). While Krupp knew that Tinidur could be improved by increasing the Ni content from 30 to 60 percent, there was a recognition that Ni would not be available. The Ni content was therefore left at 30 percent. Similarly, work on cobalt-based alloys was also shelved due to a shortage of cobalt." (Journal of Engineering for Gas Turbines and Power, October 1997, Vol. 119)

The same articles also references the material compositions for both Tinidur and Cromadur:

Tinidur - 15% Cr, 30% Ni, 2% Ti, 0.8% Si, 0.7% Mn, 0.15% C, balance Fe. This composition is similar to today's A286.

Cromadur - 18% Mn, 12% Cr, 0.65% V, 0.5% Si, 0.2% Ni, 0.12% C, balance Fe.

The 004B engine also had less than 5 lbs of chromium, as opposed to 7, as stated above.

[davebender]

The RLM got serious about jet engine development during the summer of 1939. Why didn't the Luftwaffe CiC, who was also in charge of the German economy, make a serious effort to stockpile steel alloy ingredients obtained from the Soviet Union and Finland?

[psteel]

Originally Posted by davebender

The RLM got serious about jet engine development during the summer of 1939. Why didn't the Luftwaffe CiC, who was also in charge of the German economy, make a serious effort to stockpile steel alloy ingredients obtained from the Soviet Union and Finland?

Hitler was absolutly against any sockpiling of resourses for war, since it was costly and he never believed his plans would require such a mobiliztion of effort up until the mid 1940s. He believed he could steer Germany through to the mid 1940s ,without major war. Poland leading to WW-II was not supposed to happen in Hitlers books.

[davebender]

According to Albert Speer, who was in a position to know, chromium was the worst resource shortage. After Germany evacuated the Balkans they could no longer import chromium from Turkey. Perhaps this was the primary reason to forego production of the Jumo 004A engine.

Germany resource stockpile as of November 1943.
(data is from "Inside the 3rd Reich")
19 months. Manganese
10.6 months. Wolframite (i.e. tungsten)
10 months. Nickel.
7.8 months. Molybdenum
6.4 months. Silicon.
5.6 months. Chromium.

During January 1944 Speer improved the transport of Nickel from Petsamo in order to increase the German nickel stockpile. Evidently ore transport to Germany was the bottleneck rather then mine output. There was a significant stockpile of nickel ore at the mine site awaiting transport.

[psteel]

Originally Posted by veloracer

The excerpt below may answer some of your material questions:

"In 1936, when development work on the Jumo 004 started, a high-temperature Krupp steel known as P-193 was available. This material, which contained Ni, Cr, and Ti, could be given good high-temperature strength by means of solution treating and precipitation hardening. Krupp developed an improved version of P-193 known as Tinidur. It was of the same type as Nimonic 80, which was used in British Gas turbines from 1942 but contained over 50 percent iron (which was replaced by Ni in Nimonic 80) and this caused a rapid drop in creep strength at 1080F (compared to 1260F for Nimonic 80). While Krupp knew that Tinidur could be improved by increasing the Ni content from 30 to 60 percent, there was a recognition that Ni would not be available. The Ni content was therefore left at 30 percent. Similarly, work on cobalt-based alloys was also shelved due to a shortage of cobalt." (Journal of Engineering for Gas Turbines and Power, October 1997, Vol. 119)

The same articles also references the material compositions for both Tinidur and Cromadur:

Tinidur - 15% Cr, 30% Ni, 2% Ti, 0.8% Si, 0.7% Mn, 0.15% C, balance Fe. This composition is similar to today's A286.

Cromadur - 18% Mn, 12% Cr, 0.65% V, 0.5% Si, 0.2% Ni, 0.12% C, balance Fe.

The 004B engine also had less than 5 lbs of chromium, as opposed to 7, as stated above.

Thanks for the update. I have some questions . Where does the reference for 5 lb chrome comes from for the Jumo-004B? I have read of 7 lbs and 3.2 kg .

In that paper I referenced for the HeS-011, there was another reference to an article on Bentele, so I down loaded it. In there is a document reproduction that shows Ernst Heinkel detailing how the new "Topfschaufel" blade design is drawn out. The doc is dated Aug 26, 1944 and it details the Cromadur alloy as "CMV-spezial", with 13% Chrome, 17% Manganese, 0.8% Vandinum & 0.11% Carbon. This is said to be a refinement of the earlier blade design and was to be used on the HeS-011 engine. Im not quite sure about the reference but it seems to suggest the temperature range is from 1100°F to 800°F. I wonder if this is the improved alloy that was referenced in the Aviation article from 1946 and posted previous. Any thoughts?


Here is the link for that article .....

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[veloracer]

The 5 lbs chromium comes from the same article that I reference above:

"With the hollow Cromadur sheet metal blade, the complete 004B engine had less than 5 lbs chromium." However, the article does not cite a reference for this particular statement. Maybe the 7 lb reference is taking into account the solid blades, and not the sheet metal blades?

[psteel]

Originally Posted by davebender

According to Albert Speer, who was in a position to know, chromium was the worst resource shortage. After Germany evacuated the Balkans they could no longer import chromium from Turkey. Perhaps this was the primary reason to forego production of the Jumo 004A engine.

Germany resource stockpile as of November 1943.
(data is from "Inside the 3rd Reich")
19 months. Manganese
10.6 months. Wolframite (i.e. tungsten)
10 months. Nickel.
7.8 months. Molybdenum
6.4 months. Silicon.
5.6 months. Chromium.

During January 1944 Speer improved the transport of Nickel from Petsamo in order to increase the German nickel stockpile. Evidently ore transport to Germany was the bottleneck rather then mine output. There was a significant stockpile of nickel ore at the mine site awaiting transport.

These could be good figures but without mass figures they can't help alot. For exampe the amount of chrome looks low.But in 1939 Admiral Raeder submitted a request for the amount resources & manpower needed for the "Enlarged Uboat construction Plan", from 1940 on. This plan envisaged completion of the 5 big ships [GZ ,Sey, Pr E Bism & Tirp] plus a yearly production of 7 destroyers 9 Gross Torpedoboot and 60 Mineboot plus 275 Uboats per year . These monthly resources required were listed at....

195,000 tons of Steel & Iron
5850 tons Copper
3900 tons lead
342 tons Tin
274 tons nickel
2950 tons Aluminum.
120,000 work force.

Rossler "The Uboat" pp 122-125.

Now atleast 1/2 of the steel and iron was to reconstruct the ship yards from producing mostly warships to producing mostly Uboats, and another 1/4 would be for munitions to supply the fleet, but even 1/4 of that amount is still 600,000 tons warships/U boats per year. If these warships all require St-37/44/52 steel , thats roughly 1 kg of Nickel per ton or 600 tons Nickel. Heavier warship armor is about 3-4 % nickel so given armor of 17500 tons for each battleship and about 6000 for the carrier plus 4000 for each cruiser, thats ~ 50,000 tons... of which 1900 tons nickel, or 210 tons nickel per month total .

The left over resources could provide atleast 768 tons nickel per year [64000kg x12=768,000 kg nickel]. If each Jumo 004 engine has 60% nickel in the hot section , thats ~16kg nickel per Jumo 004 [@ 60% nickel] ....thats 48,000 jet engines per year that could be built, if strategic metals were the limiting factor.

The above plan was not approved, but an amount 2/3 of it was approved, provided the capital ships and 1/2 the surface fleet was sacrificed to produce ~ 325 Uboats per year instead of 275 Uboats per year.

[davebender]

I wonder how much chromium was devoted to naval construction from 1942 onward (i.e. when the Jumo 004A engine was ready for production)? Speer states that chromium was essentialy for virtually all weapons production.

[razor1uk]

A wealth of info both about the Jumo 04's and the tangental topic info metalurgical composition and Rieche resources, congrats peoples. As allways, informatively excellent pdf links. Keep it up guys!