Militarysta Posted March 9, 2020 Report Share Posted March 9, 2020 http://www.witu.mil.pl/www/biuletyn/ptu_2020/151/97.pdf Quote OPTIMISATION OF BALLISTIC PROPERTIES OF NANOSTRUCTURED BAINITIC STEEL PLATES FOR CONTAINER ARMOUR SYSTEM The reduction of the armour system mass was estimated to 32-37%due to the use of the innovative grade of steel. Beer and Lord_James 2 Quote Link to comment Share on other sites More sharing options...
Lord_James Posted March 9, 2020 Report Share Posted March 9, 2020 Huh, that’s weird, usually Bainite is undesired for armor or structural components due to excessive brittleness: http://navweaps.com/index_nathan/metalprpsept2009.php#Bainite pearlite being just as tough but less brittle (on average) and martensite also being less brittle, and even tougher. Unless they want the contents of the container to fall out after the first hit, like ERA or something similar, this doesn’t look like an advancement. Quote Link to comment Share on other sites More sharing options...
Zadlo Posted March 9, 2020 Report Share Posted March 9, 2020 You say "brittle"? The same steel after bending test. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 This is what also called pizza bainite, super bainite, etc It is (nothing more, nothing less) than replicating the bainitic matrix of ADI (Austempered Ductile Iron) in a steel. There are attempts to sell this as armour, for instance PAIVSE 600 https://www.tatasteeleurope.com/en/news/news/2013/2013_lightweight_armour_steel_trade It is very suitable for making in a perforated state, it can be supplied "soft" then punched/machined/rolled, and then austenised and controlled (slow) cooling for final hardness/strength. the main problem with this grade of steel, is that it requires a high carbon content (and high silicon) to drive the grain refining process to make it both tough and strong, unfortunately, that also makes not suitable for welding. Both PAIVSE 600 and it's Polish equivalent seem to have attempted to replicated superbainite, while keeping carbon low enough to be close to/within some other grade of steel, its still not suitable for welding, but its easier to source than purely optimized super bainite, although it not as good ballisticly as higher carbon versions. This style of steel was kinda accidental discovered by Francisca Caballero in Cambridge UK around the year 2000, by 2006 https://www.phase-trans.msm.cam.ac.uk/2006/ICASS.pdf https://link.springer.com/article/10.1007/s11665-013-0557-4/tables/2 Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 http://msmsjec.blogspot.com/2016/08/super-bainite-high-hardness-steel.html Commercial Super Bainite Steel is low alloy –4.7% (Si Mn Cr Mo) –0.8% C -with no Al, Co, Ti, Ni. Proof Stress at 0.2% (0.2PS -Rp0.2) is -1673 MPa Ultimate Tensile Strength (UTS) (RMm) is -2098 MPa Elongation (El) is 11% Reduction of Area (RA) is5% Charpy Notch Impact number 5 Joule -based on a 10mm x 10mm specimen at room temperature Vickers Hardness (HV30) of 690HV30 Brinell (10 mm Ball, 3000 kg load) of 574HBW Rockwell C (20 degree cone 150 kg) of HRC 57 Available in a fixed width of 1250mm up to 5.5m length and two gauges 6.3mm & 8.5mm. Made as a Pearlite -easy to process Ballistic mass efficiency of 2.5 in a perforated steel armour system increasing the Carbon, and or adding Al,Co are the main ways to improve this steel. The key takeaway is that this is a lower cost/ lower performance version Beer 1 Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 https://impact.ref.ac.uk/casestudies/CaseStudy.aspx?Id=24686 it was originally developed from considering gun barrels, austenised steels can have superior properties to QT when the service tempertures go above QT' tempering temperature. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 This technique could've been applied to silicon spring steel circa WWII if people had known about it, also it is very suitable for casting, it would've allowed for superior cheap cast turrets fro Soviet or Israeli tanks, but that era is over. Quote Link to comment Share on other sites More sharing options...
Lord_James Posted March 10, 2020 Report Share Posted March 10, 2020 After getting some time to read through the article provided by @Militarysta (thank you), I can sorta see how they can pull it off: Manganese and Silicon are both great for making strong steel, manganese increasing the harden-ability of low carbon steels, and silicon also increasing the harden-ability, and having the added benefit of maintaining the harness after tempering. http://navweaps.com/index_nathan/metalprpsept2009.php#Manganese http://navweaps.com/index_nathan/metalprpsept2009.php#Silicon The retention of the bainite is still a mystery to me, as tempering and annealing (as discussed in the article) would transform the bainite with the remaining austenite into a more stable structure (again, pearlite), though maybe the large amount of silicon present (1.56-1.61% by mass) is interfering? I’m curious too see how this armor develops, if they can make the plates thicker, or if they can keep the quality control while making these plates on a full industrial level. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 https://webarchive.nationalarchives.gov.uk/20140402150936/https://www.dstl.gov.uk/downloads/20110914-Super_Bainite_Steel_PN_-_FINAL1.pdf (i would add a youtube of this armour in action, but i cant seem to link youtube) Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 watch?v=uW9uxb-_2zw (attempting youtube link) Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 https://www.ploughshareinnovations.com/technology/super-bainite-steel/ more brits trying to sell bainitic armour https://www.dsei.co.uk/exhibitor-products/ultra-high-hardness-lightweight-steel-for-armour Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 1 hour ago, Lord_James said: After getting some time to read through the article provided by @Militarysta (thank you), I can sorta see how they can pull it off: Manganese and Silicon are both great for making strong steel, manganese increasing the harden-ability of low carbon steels, and silicon also increasing the harden-ability No, that is not how it works in this case. by far the greatest source of the strength is the fineness of the structure, which is depended upon carbon to drive it, silicon to stabilize it, and soak time at a suitable temperature to let it occur. This stuff really is the steel matrix from Austempered Ductile Iron, but soaked at around 200 to 300 Celcius, thus the name pizza because it cooks really well at 200 celcius. (and usefully, a 200Celcius cooked bainite retains its strength to temperature like 500 Celcius, which is different to how QT steels work) Quote Link to comment Share on other sites More sharing options...
Kal Posted March 10, 2020 Report Share Posted March 10, 2020 21 hours ago, Militarysta said: http://www.witu.mil.pl/www/biuletyn/ptu_2020/151/97.pdf If you look carefully, (page 105) you can see they are comparing TT optionTemp. in °C/time in h ie 210 Celcius for 116 hours is the 210/116 likewise 220 Celcius for 72 hours is 220/72 etc (this would be faster with higher C, or added Co or Al) Quote Link to comment Share on other sites More sharing options...
Zadlo Posted March 10, 2020 Report Share Posted March 10, 2020 Militarysta has shown only one part of the subject. Here's the second, more material part. https://www.docdroid.net/eErYUPU/jmm-2-marcisz.pdf?fbclid=IwAR14GTxI9wUzmz4mHTv_jq4aNHNmHPUI7ipN0Za9faXAxH5clGpWlxZYxuU There's a third part too but that would only disguise the origin of this steel. I can only say that this Polish grade steel is a reverse-engineered version of some well known nanostructural armor steel. The thickest steel plates which was made by Poles were 10mm (0,4") thick and there will be two production lines in Poland. One in Labedy mechanical plant, second in civilian part of Huta Stalowa Wola which is the main Polish producer of military grade steel. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 11, 2020 Report Share Posted March 11, 2020 With some preheat and postheat, can the polish bainite armour provide a manageable weld? Quote Link to comment Share on other sites More sharing options...
Zadlo Posted March 11, 2020 Report Share Posted March 11, 2020 Ito-Bessyo formula isn't good for steels with more than 0,16% C. In this case better is the formula from International Institute of Welding And according to this CEV is 1,31% which means this steel is not good for welding unless you heat it up to ~370 Celsius degrees. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 11, 2020 Report Share Posted March 11, 2020 So its about double the CEV as Australian Bisalloy UHH 600. https://www.bisalloy.com.au/wp/wp-content/uploads/2019/12/BIS0421-2019-11-11-C1L2P1-Data-Sheet-Armour-UHH600-Steel_WEB.pdf But bainite has some nifty temper resistance properties, so you might be able to weld and stress relieve to above 370C if desired. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 11, 2020 Report Share Posted March 11, 2020 Just how much carbon is in the polish bainite? Quote Link to comment Share on other sites More sharing options...
Zadlo Posted March 11, 2020 Report Share Posted March 11, 2020 7 minutes ago, Kal said: Just how much carbon is in the polish bainite? Well Quote The examined material consisted of sections of nanostruc-tured bainitic steel (NBA) with the following composition Fe-0.58%C-1.9%Mn-1.8%Si-1.3%Cr-0.75%Mo (weight %) Quote Link to comment Share on other sites More sharing options...
Kal Posted March 11, 2020 Report Share Posted March 11, 2020 Thanks, so they are staying at .58 or 0.60 typical levels of C. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 12, 2020 Report Share Posted March 12, 2020 General query If anyone has contacts in commercial casting and heat treating nano bainite please pm me. I have a consumable product approx 25mm by 50mm that i'm considering transitioning to that variety of production. Quote Link to comment Share on other sites More sharing options...
Zadlo Posted March 16, 2020 Report Share Posted March 16, 2020 On 3/11/2020 at 12:20 AM, Zadlo said: There's a third part too but that would only disguise the origin of this steel. I can only say that this Polish grade steel is a reverse-engineered version of some well known nanostructural armor steel. The thickest steel plates which was made by Poles were 10mm (0,4") thick and there will be two production lines in Poland. One in Labedy mechanical plant, second in civilian part of Huta Stalowa Wola which is the main Polish producer of military grade steel. Oh, my fault. That's domestic design with Western-style name. The steel is called NANOS-BA. And thickest steel plates made were 15mm thick. I'll send the main article where the modern Polish armor steels (also maraging and amorphous) are presented but first at all I need my PC back. Quote Link to comment Share on other sites More sharing options...
Kal Posted March 21, 2020 Report Share Posted March 21, 2020 http://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-article-BWA0-0055-0001/c/httpwww_bg_utp_edu_plartpm42012nr204120garbarzburian20marcisz20wic59bniewski20pm202920s_207-22.pdf The Nano-Duplex NANOS-BA Steel for Application in Construction of Armors Quote Link to comment Share on other sites More sharing options...
Zadlo Posted March 21, 2020 Report Share Posted March 21, 2020 On 3/17/2020 at 12:02 AM, Zadlo said: I'll send the main article where the modern Polish armor steels (also maraging and amorphous) are presented but first at all I need my PC back. Oh, here you got. https://www.docdroid.net/f3hlFm2/bgarbarz.pdf Quote Link to comment Share on other sites More sharing options...
Collimatrix Posted July 30, 2020 Report Share Posted July 30, 2020 I have learned enough about ferrous metallurgy to contribute to this discussion. Sooooo... Bainite itself isn't brittle. Bainite itself is fairly tough, but less hard than the more typical tempered martensitic steels used for armor. However, a funny thing can happen during the formation of bainite. Bainite doesn't just form; it grows within and eventually replaces crystals of a phase called austenite, like so: This is done during a special heat treating process called austempering. Compared to other heat treatment processes, austempering is fairly slow, but it also produces low amounts of warpage and cracking in the steel, works well with simple and cheap low-alloy steels, and does not require any secondary processes like additional tempering after it is done. What can happen during bainite formation is that the growth of those little lathe crystals segregates out impurities like sulfur and phosphorus, piling them up into dense bands that promote crack propagation. There are ways to counteract this, but if the bainite/pearlite formation was an unintended side effect of an imperfect heat treatment in the first place, then they probably didn't do anything to counteract it. Also, steel mills today are probably a bit better at removing the sulfur and phosphorus in the first place. Small grain size is desirable regardless of the microstructure of the steel. The Hall-Petch strengthening mechanism is of considerable interest because it is one of the few mechanisms that simultaneously improves the hardness and toughness of steel. Lord_James and LoooSeR 2 Quote Link to comment Share on other sites More sharing options...
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