Matilda II was both cast, thicker and larger than APX-1, so the limit wasn't really reached.Castings usually aren't as strong as rolled plates, but (once you have the technical knowhow to make them big enough[1]) remove pr massively reduce the need for forming, cutting and welding all of which can reduce overall strength, create local weakpoints and take time [2].
[1] see Somua S35 for a good example of a decent cast tank that suffered from a one man turret. While political preference for the smallest possible crews played an important part, French casting technology though world class was about at its limit. Even if a two man turret was wanted, it may have been a step too far in the 1930s, and 1940 was too late. There was at least one French medium with a 2man turret but I'll have to check if it was cast.
[2] Big castings need carefully controlled cooling to avoid distortion, cracking and metallurgical problems like excessive brittleness or low hardness. It can take days to do properly, but the actual labour hours overall can be less than welding forming etc even if the total number of hours elapsed is the same.
Acually I do not. I just go with the good old "mhhh, looks good." aproach.You do realise that rolling armour into a curved shape weakens the armour? Which is why it has largely been abandoned in building tanks...
Basically in the 1950s for most combatants...Acually I do not. I just go with the good old "mhhh, looks good." aproach.
But interesting, when did the curved shape design get abandoned?
Good point. But not that you can't have bigger casting, but that the combination of metallurgical knowledge of the day and available mould making and cooling experience and expertise, plus having time and capacity to experiment and then to change production. It's unlikely that different manufacturers would share development with competitors, especially in different countries.Matilda II was both cast, thicker and larger than APX-1, so the limit wasn't really reached.
As I said, the Panther's mantlet was cast into it's final shape, not forged. I know of no instance of the Germans using curved armor forgings for the frontal armor of a production tank. Because the Indien-Panzer specifically had a dome-shaped turret design that could only be cast, I see no reason to expect the mantlet to be forged instead. Curved castings in general are materially indistinguishable from flat castings, which is why casting is usually used to make curved armor pieces. Because they preferred welded construction, the Germans only used casting for relatively small armor components in their tanks, but that included the Panther mantlet, Tiger I mantlet, and Tiger II mantlet.The Panther and Tiger II(P) both suffered from weakened mantlets because of armour rolling. The Sentinel was unique because of the size of it's castings but did not suffer from weakened armour.
Large German casting, 1890 Brandenburg classFrench casting technology though world class was about at its limit. Even if a two man turret was wanted, it may have been a step too far in the 1930s, and 1940 was too late
Actually, smaller casting is way harder than larger casting. As you start getting into the problem of miniaturization, ie precision and Cooling time.Castings usually aren't as strong as rolled plates, but (once you have the technical knowhow to make them big enough[1]) remove pr massively reduce the need for forming, cutting and welding all of which can reduce overall strength, create local weakpoints and take time [2].
[1] see Somua S35 for a good example of a decent cast tank that suffered from a one man turret. While political preference for the smallest possible crews played an important part, French casting technology though world class was about at its limit. Even if a two man turret was wanted, it may have been a step too far in the 1930s, and 1940 was too late. There was at least one French medium with a 2man turret but I'll have to check if it was cast.
[2] Big castings need carefully controlled cooling to avoid distortion, cracking and metallurgical problems like excessive brittleness or low hardness. It can take days to do properly, but the actual labour hours overall can be less than welding forming etc even if the total number of hours elapsed is the same.
Of course our good old friends, the Russians, were still using cast homogeneous steel armour to produce the turrets of their comedy T-72 for… well, forever. To be fair, they have added various bits and pieces over the years to try and improve things, ERA, rubber sheets and what now looks like bed frames. Bless!Basically in the 1950s for most combatants...
True. Small castings are very tricky. I saw some very impressive titanium 3D printed items a few years back which might provide an alternative.Actually, smaller casting is way harder than larger casting. As you start getting into the problem of miniaturization, ie precision and Cooling time.
Acually I do not. I just go with the good old "mhhh, looks good." aproach.
But interesting, when did the curved shape design get abandoned?
Basically in the 1950s for most combatants...
Usually when composite armor layers were adopted, so in the 1960's to the 1970's for most nations. The Soviets were limited by budget so they couldn't really abandon them until after the Cold War ended, but a summary of this switch to welded turrets for the USSR and Russia is found here.Of course our good old friends, the Russians, were still using cast homogeneous steel armour to produce the turrets of their comedy T-72 for… well, forever. To be fair, they have added various bits and pieces over the years to try and improve things, ERA, rubber sheets and what now looks like bed frames. Bless!
Those I think were riveted, based on the more modern photos. But you can see a surviving example of the cast fortress turret at Fort Copacabana, with a cast twin 12" gun turret (it's probably one of the largest single-piece cast turrets made).Large German casting, 1890 Brandenburg class
Actually the largest Gruson turrets (the twin 40 cm gun turrets) were cast in multiple pie-shaped sections and assembled together, so those were asymmetrical. More specifically the turret sections had this form:True. Small castings are very tricky. I saw some very impressive titanium 3D printed items a few years back which might provide an alternative.
I suspect the big fortress turrets etc were relatively easy shapes to cast because they are fairly symmetrical, so not so much risk of warping, but also the kind of thing you can cast very thick to get sufficient strength without fancy alloying elements.
US casting technology as used on the Lee was very good, but the Somua S35 was mid 30s technology - hence the body cast in a few pieces and assembled using gudgeon pins [1].
[1] worth responding just to use the word gudgeon.
You might find this of interest:Does anyone know from the top of their head the Sherman tank variant that would be best placed to stop T - 34 / 85s?
Would a Sherman Easy Eight with their 76 mm gun be able to do so or would they need different ammunition? Just reading a book on the Korean war atm.
Thanks heaps .
We talked a little about this a couple of months ago I think.Could similar vehicles be fielded by UK USSR USA as ATGM armed modern tank destroyers, maybe lower silhouette, portable light and decent speedWiesel AWC tankette (1985)
West German Wiesel AWC tankette (1985), used for th Fallschirmjäger units (paratroopers) of the Bundeswehrwww.tanks-encyclopedia.com