Most people don't get it. Titanium is not as strong as steel, only about 90% the strength of steel, depending on the alloy. But it is light as aluminum. So you have almost the strength of steel, but for a bargain of its weight. That is the magic of titanium. But it is expensive and its high melting point makes it unbelievably complicate to weld.
Not quite the same density. Aluminium density is 2.7 tons per cubic metre whereas Titanium is 4.5 tons per cubic metre. Steel ranks at 7.1 tons per cubic metre; for comparison sake Magnesium is 1.7 tons per cubic metre. Where Titanium scores mostly is heat tolerance ( hence its use in aeronautical uses) & corrosion resistance ( in chemical industries & maritime environments) being better than bronze or stainless steel. One has to carefully establish the intended purpose before deciding on which metal or alloy to use . Hope this helps. Kind regards.
Bolted connections rely on the tension of the bolt. The clamp force clamps the parts together tight enough to keep them from sliding. The bolts, under tension, provide the clamping force. Bolted connections are not designed to use shear strength to hold the connection. The first test is a sheer test. The second test is tension load.
Agreed. Many flaws in the experimental design. The material may have the same name ,I.e. titanium, but the alloy and material condition needs to be considered too.
Nice! It's quite impressive in general what just one bolt can hold. The most benefit from using titanium is indeed the weight to strength ratio. Apparently to just hold a certain force, there is no real reason to chose titnium over steel (high strength steel, such as the the 12.9 bolt, is better then). But it's much lighter (the density is not much more than half that of steel), so compared to it's weight, it's stronger. This is important for a space shuttle that might have quite a lot of bolts. Maybe the corrosion resistance is also better for titanium?
I believe titanium is also better in situations where temperatures fluctuate. That is certainly true in the space, depending on the location of the bolt.
It is true that this weight/strength ratio is very advantageous for titanium, because for the same weight we can put a larger titanium screw, therefore much more resistant than the same one in steel, of equivalent weight but which will be smaller
it also has way better heat and corrosion resistance, and its not even that rare on earth. but the downsides are its not quite as strong as the best steel, and its insanely hard to process and machine which makes it really expensive
Probably the bolt from the shuttle is made of pure titanium, and the Chinese one is an alloy. Titanium VT6 and so on are very durable, but how they behave at low/high temperatures is not clear.
Good point. Depending where the bolt was used (inside, outside), the Buran space shuttle will endure extremely high and very low temperatures in practice (though, iirc, there was only ever one test flight).
It is true that this weight/strength ratio is very advantageous for titanium, because for the same weight we can put a larger titanium screw, therefore much more resistant than the same one in steel, of equivalent weight but which will be smaller
Also the bolts from the Buran program have been sitting about for decades - some amount of oxidation has probably occurred over time. (In addition to “we have no idea what kind of alloy it was” …)
That's also what i think , but it just might be the tests . The cheap ones are as is. 5tonns +-25% , but mostly held at +-5% , but the wont throw away a batch for a 25%+- . The expensive is proven to 4.785tonns +-3% or something and always held close to the tested value . In my experience in manufacturing just because something can have a +-1mm tolerance , that does not mean that someone is deliberatly adjusting every part to max out the tolerance . This just means the production can run smoothly and a whoopsie here and there won't matter . Any good worker always tries to maintain the middle of a given tolerance .
I have a fun fact for you..we are talking 15 years ago when chinese quality was on the rise, now it has strongly declined two packages were mixed up german factory received it opened and QC department immediately called to announce the mistake, chinese factory ? assembled 500'000 modules with wrong part attached...it wasn't even the same size they forced them on, that's all you need to ever hear about chinese quality 0/500'000 quality check and not even a look on the part number or nothing, no alarms or checks on the machines too as the size and markings should be checked by cameras
@@fredEVOIXwhat you pay for is what you get, even chinese products can be good, but really only what companies buy from example. Because companies pay almost anythhing if the products goid and holds up, there is incentive too make quality products. On the other hand aliexpress stuff for the masses made with other priorities.
In addition to some of the other comments, you can hear that the pressure applied to the first two bolts was done at an accelerated pace than the "Chinese Titanium". On that one, the press was working a lot slower. I don't know if this was intentional or not, but it obviously matters.
Isn't the shear test for the titanium bolt sorta flawed? I get you had to add to it because the threads didn't go back far enough but wouldn't that slightly change the test also with the test test wouldn't having the jig the same for all be more accurate? The first two bolts you had it spun slightly (again I get it was for clearance) but having it slightly turned like that would cause some amount of twisting when you put strain on it right?
Did you fasten the bolts with proper torque? Did you use same class nuts? Did you use them beyond elastic phase to proper use 100% or almost 100% of theirs strength? Just doubts, because such things may affect the end result of the screwed connection.
Depends what the bolts were made for. In many serious applications they have a deliberately designed failure point. Bolts are not typically made as strong as they can be (the Chinese one is perhaps) as in many applications the bolt failing at a certain load is an engineered safety feature.
If the space bolts came from actual spacecraft, there is a LOT of metallurgy improvements since the Russian fasteners were made. Would be interesting to see a modern space fastener comparison
You should add some slotted bolts to your fixture so the plate stays together. Less to pickup and reset each time. The center bolt remains the same for sheering.
A lot of people are missing the point of titanium. It's getting similar strength as steel at almost half the weight. Every gram is calculated when designing a space craft.
Sometimes you need things fail. If making an emergency landing in a plane and its wing strikes a large tree you would want the wing to break off, that way it might not spin the plane and might slow its progress. Sometimes stronger is not always better.
I have a feeling that this is a test of screw's thread on the first place, then its match against the bolt's thread, finally screw's elasticity and hardness. Screw's material that is a compound could probably give better results. Threading could be manufactured in different way leading to smoother surface impacting the forces. Notice that screw is not stretching but instead there is a single "jump" acting like a hammer leading to not only thread under the screw being broken but also other have no chance to resist.
The thing with space shuttle bolt is not that thay are stronger, but if you test 1000 of them non of wil under perform, where as the cheeper bolts are more likly to have production faults
i'm surprised that in the pulling apart test the bolts broke instead of ripping of the threading. seems like way less material has to move or break to remove the threading than just breaking the bolts.
Pretty much every aliexpress titanium bolt/screw I have ever bought for my bicycles has been listed as 6AL/4V, TC4 or GR5 (all the same thing) so perhaps it's safe to assume they are of that grade. Perhaps?
it's common in europe to use a comma instead of a dot/period for decimal points, so: 9.92g (US) = 9,92g they also swap them for thousands: 100,000 pieces (US) = 100.000 pieces
I didn't expect a test in situation mounted as it would be used super cool :) please remember ali items are sold at a loss by the sellers, it's the CCP subsidies and us paying them in hidden ways, only learned it recently but when they offer free shipping it's actually our tax dollars that pay it >< because of political shenanigans China is considered an under-developed country and so it's out post and our money that pay the shipping >
It wasn't done properly, and the Chinese bolts were titanium coated steel. Plus, there are some bolts that have the threads pressed in instead of cut, so that would be necessary to know too
Unsure if the space shuttles metal is deliberatly more malleable to allow for the heat going between atmosphere and space since you want the metal to behave to some degree in many climate extremes. Too hard can shatter, too soft will snap, both issues are bad,
sometimes its good, sometimes its like the guy who bought new rtx gpu fans to replace the original noisy ones, the cable plug was with the poles switched... looking back at it, now he has a $1000 paperweight...
EXACTLY! Finally, someone who sees the obvious. If it has a flathead... that doesn't even qualify as a bolt! It is just a screw. There is a huge difference between a bolt, and a screw. Thank you, for pointing people straight.
Compare the weight of the Bolts. I bet the space ones are lightest. And that was the requirement. Be as light as possible but at least as though as steel. If the AliExpress bolt weighs the same than the space bolt, yes go with it, else you will need A LOT more rocket fuel to lift the extra weight of these thousands of nuts built into the space ship to space. Also, how brittle or plastic would those bolts get in which temperature regimes? Idk if it is that important here, but there is more complex things to consider going to space than pure strength. Even production costs, dependance on imports vs sanctions etc.
Nice video. But why do you measure force in kg and not in N (Newton)? I understand what you mean (the force equivalent to the weight of that mass, factor g=9.81 N/kg), but it would not hurt sticking to standard units when doing measurements. Also, it seems to me you compare bolts (screws) of differing diameters here. Thirdly, "AliExpress" is not a supplier, it is a marketplace.
Use pounds, be a real American! LOL! Look on Earth, pounds and kg ARE standard units!! As an Engineer, I could not give a hoot about the units, because we (us engineers) all know the difference between weight and mass - as that was day one physics.
Hi, you do not pay enough attention to very important details due this tests. If the bolt is not fitted tightly as this Russian bolt you elongate a bolt in the same time when you try to make share stress perpendicular to it (a case with Alli express bolt). Bolt cannot change en angle when mounted to steel slabs.This is causing that part of the force working along the bolt making looks it much stronger. I assuming that the whole diameter was slightly to big for Ali express bolt. You can see an angle between a head of the bolt and the slab develops during a test visible by naked aye so at lest 1-2 degrees.
you do understand that this is not a controlled test by any means the design of the screws are way different than each other not to mention that there is probably Gauge difference between the screws in your test. and this was fun and all but it would have been cooler if you mentioned these sort of stuff although it probably would have taken out the fun of seeing David beating the goliath out of this video although David is probably thicker and have a different design and mixture from the goliath.
The titanium bolts from the old shuttle…were from the Cold War era? Cast titanium? Impure? Nowadays everything is CNC machined from a chunk/block of metal/material…? Even though it’s from China, the production and manufacturing has improved from 50 years ago.
in the first test the bolts were the same thickness. in the 2nd test some bolts were thicker than those from aliexpress. Not a fair fight. Aliexpress was thinner than the 2 other bolts. He had to get bigger bolts to overcome Aliexpress an 8.8mm bolt against a 12.5mm is not fair. I say Aliexpress won.
Somun olan test yanlıştır. Somunsuz çekme koparma olmalıdır plaka kesit şeklinde ..Ayrıca makine çekme ve delme hız değerleri de sunulmaldır .. bu değerler sadece genel bir fikir verebilir ..
As an engineer, I noticed that the bolts you are testing... None are the same size!! Also, you have not given any part numbers! Even in same size bolts, there are multitudes of specifications, beyond a 8.8 or 12.9 commercial bolt. So breaking random bolts with a hydraulic press, really means nothing without the data to back it up. As an engineer, who used to select nuts and bolts for THE Space Shuttle (the real one, not the Buran piece of crap, that never even flew to space), I have to say that we (obviously) had access to a lot of stuff, not found in the typical Grainger's catalog - or any catalog. What most people do not understand, is that is is not just about the weight, or the strength, or even a dozen different factors! It is ALL of those factors, AND MORE, that will drive fastener selection. The first step being a good design, before you even begin to think about the fasteners. If you really want to impress me, show me the specification shear and tensile numbers first, then see if you can test them accurately. But like everyone else... I do enjoy seeing things destroyed by A HYDRAULIC PRESS, LOL!!
