Sablja Damiskija

[stalker]

Jeste da nema veze sa hobijem ali postoji dosta ljudi sa ovog foruma kome će biti interesantno, radi se o analizi poznatih čelika sa aspekta savremenog naprednog metalurškog sna o super čelicima :

http://instroncommunity.blogspot.com/20 ... anced.html

Damascus Swords - An Ancient Advanced Material
In popular culture, the Samurai sword reigns supreme as both a fearsome weapon and a work of art, a masterpiece combining hardness and flexibility in steel. However, another ancient weapon, the Damascus sword, has also been revered for centuries. Its beauty is second to none. Damascus blades have a characteristic wavy banding pattern on the blade surface known as damask. It also combines hardness and flexibility. Only recently, researchers have found some of the secrets of these competing properties. The Damascene bladesmiths were making carbon nanotubes more than 400 years ago.

Damascus blades, first encountered by Europeans in the Middle Ages in the Middle East and Asia, had features not found in European steels: extraordinary mechanical properties, an exceptionally sharp cutting edges, and a damask pattern.

Damascus blades were forged from Wootz steel from India. India has been reputed for its iron and steel since ancient times. Literary accounts indicate that steel from southern India was rated as some of the finest in the world and was traded throughout Europe, China, and the Middle East.

Steel is made by alloying iron with carbon. High carbon contents of 1 - 2% make the material hard, but also make it brittle. This property is useless for sword making since the blade would shatter upon impact with a shield or another sword. However, Wootz steel, with a carbon content of about 1.5%, showed a seemingly impossible combination of hardness and malleability.

According to an early report on Indian Wootz steel production, iron ores taken from particular mines in India contained small traces of impurities; the metals including vanadium, chromium, manganese, cobalt and nickel. Other particular ingredients were necessary in the smelting process: wood from Cassia auriculata and leaves of Calotropis gigantea.

Wootz steel was produced as small ingots and shipped to Damascus, Syria, where bladesmiths learned to forge them into the swords that displayed a beautiful surface pattern. The high carbon level of these steels plays a key role in producing the characteristic surface pattern because the pattern results from alignment of the cementite (Fe3C) particles that form in such steels on cooling.

Unfortunately, production of Damascus swords gradually declined, ceasing by around 1750, and the process was lost to bladesmiths. Several theories have been put forward for this decline, such as exhaustion of the supply of iron ore of the correct composition, disturbance of trade routes, and loss of knowledge of the smithing process through secrecy over time.

Nowadays, the term Damascus steel refers to two different types; one of which is the true ancient Wootz Damascus steel with a texture originating from the etched crystalline structure, the other is a composite structure made by welding, folding, and twisting of alternating layers of iron and steel to give a visible pattern on the surface of the final blade.

The legends associated with the excellent properties of Wootz steel and the beautiful patterns on Damascus blades caught the imagination of European scientists in the 17th through 19th centuries since the use of high-carbon iron alloys was not really known previously in Europe and hence played an important role in the development of modern metallurgy. Textured Damascus steel was one of the earliest materials to be examined at the microstructure level.

Both the internal microstructure and the chemical composition of these steels were well established by the early 1900s. The internal microstructure of a Wootz Damascus blade possessing a high-quality damascene surface pattern consists of bands of small particles of cementite clustered along the band centerline. The bands have a characteristic spacing of 30 to 70 mm and are contained in a steel matrix. The bands lie parallel to the forging plane of the blades. By manipulating the angle of the blade surface, relative to the plane of the bands, the bladesmith can produce a variety of convoluted patterns of intersection of the bands with the blade surface. After polishing and etching, the cementite bands appear white and the steel matrix nearly black, creating the surface pattern.

More recently, materials researcher Peter Paufler and his colleagues at Dresden University (Germany) using high-resolution transmission electron microscopy, have detected carbon nanotubes in a specimen taken from a genuine Damascus sabre produced by the famous blacksmith Assad Ullah in the 17th century. The nanotubes appear after dissolution of the sample in hydrochloric acid. Incompletely dissolved cementite nanowires were also identified, indicating that these wires could have been encapsulated and protected by the carbon nanotubes.

Carbon nanotubes are cylinders made of hexagonally-arranged carbon atoms. They are among the strongest materials known and have great elasticity and tensile strength. The team theorizes that the nanotubes were protecting nanowires of hard and brittle cementite. That may be the answer to the steel’s special properties; at a nanometer level, it is a composite material. The malleability of the carbon nanotubes compensates for the brittleness of the cementite formed by the high-carbon Wootz steel.

It is not clear how ancient bladesmiths produced these nanotubes, but the researchers believe that the key to this process lay with the unique combination of impurities in the Wootz. Alternating temperature phases during manufacture caused these impurities to segregate out into planes. From there, they would have acted as catalysts for the formation of the carbon nanotubes, which in turn would have promoted the formation of the cementite nanowires.

Using the unique properties of Wootz steel, and their unique blade-treatment procedures, Syrian craftsmen may have been making that most modern of material, carbon nanotubes, more than 400 years ago.

[Homer]

Svak cast, Vlado.
Ovo je fenomenalan tekst.

Sledecu stvar samo nisu uzeli u obzir.

Dosta ranije sam procitao kako su se zapravo kalile ove sablje.
Kao sto je opste poznato da bi se celik kalio tokom procesa kovanja vreli metal se naglo potapa u sredinu dosta hladniju od samog metala.
Ova sredina je najcesce obicna voda.
Za izradu ovih sablji prilikom zavrsnih prekivanja, umesto vode koriscenji su robovi.
Drugim recima tokom zadnjih 20 -tak prekivanja, umesto da metal bude potopljen u vodu, on je zarivan u stomake robova.
Ljudsko telo ima konstantniju temperaturu od bureta sa vodom, a i gusce je, sto je dovodilo do vece kohezije metala.
Prilikom nastanka ovih sablji, robova je bilo za izvoz, te ovaj proces nije bilo tesko sprovesti u delo.
Vremenom robova je bilo sve manje, i na samom kraju ih vise nije ni bilo, te vise nije bilo moguce praviti ove sablje.


Ne znam koliko je ovo verodostojno, ali je de facto podatak na koji sam naisao.

[PeraNekron]

Jako dobar tekst. Vredi procitati i o macevima kovanim u Toledu i Kyotou, gde su se svojevremeno jednom godisnje okupljali najveci majstori kovanja, kako bi kovali maceve za shoguna i carsku riznicu.

@Homer: verovatno je istina, posto postoje pouzdani izvori koji tvrde da su se neki japanski macevi nekada potapali u ljudsku krv, iz verovatno slicnih razloga, ali i ritualnih.

[Kirgan]

Sto bi onda objasnilo izumiranje tehnike kovanja, nema robova nema sablji

[No 1]

Robovi su bili nečije vlasništvo, kao krave ili ovce, ubiti 20-ak robova da bi se iskovao neki mač pretpostavljam da su mogli da obezbede samo oni najbogatiji pa verovatno nije bilo baš tako uobičajeno.

[Homer]

@ No.1.
Naravno.
Prave Damaskije su bile retke i vrlo cenjene (citaj skupe).

[opsidiannight]

Kad je beg bio cicija?

[stalker]

Samo ću kratko da dodam za ljude koji se nisu bavili metalurgijom čelika:
Kaliti , znači dovesti čelik na visoke temperature , najčešće oko 800 i više stepeni, boja jarko žuta, dobija se željena unutrašnja struktura , prostorna rešetka gvožđa koja prima legirajuće elemente koji će popuštanjem dati i naknadnu žilavost i/ili elastičnost.
Popuštanje( unutrašnjih napona ) se radi u vazduhu, vodi , ulju ili u slučajevima katana i uopšte japanskim radionicama kombinacija, ulja, gline, i čini mi se ima tu i neka fora sa izmetom nekih ptica.

Taj pripremak za kovanje u Japanu se izrađuje samo jednom godišnje, prisustvuju svi majstori za kovanje katana i svi dobijanju neki procenat materijala. Postoji članak u Politikinom zabavniku.

U susštini materija je zarazna pa istržujte malo

[novot]

Ovaj... u srpskom se kaze Dimiskija, a ne Damaskija, ma koliko to nelogichno izgledalo Moze i Shamlijanka (Damask je na arapskom Sham).

[Awakened]

Nekada davno (secanje baguje) sam naleteo na dosta argumenata protiv te price o robovima. Te da je ljudsko telo nekonzistentno, pa bi delovi ostrice dobili razlicitu cvrstinu, te da bi doslo do deformacije ostrice itd... Verovatno su neki majstori koristili krv (mada i tu pre volovsku nego ljudsku), a i verovatno su majstori pravili prezentacije svojih novih proizvoda tako sto bi ubili nekog roba (nalik onima sa dusecima), tako da je mit verovatno nastao odatle.

[Kirgan]

Ovaj... u srpskom se kaze Dimiskija, a ne Damaskija, ma koliko to nelogichno izgledalo Moze i Shamlijanka (Damask je na arapskom Sham).

Ladno nisam video taj propust u naslovu, cccc Vlado

[Pendargon]

Nekada davno (secanje baguje) sam naleteo na dosta argumenata protiv te price o robovima. Te da je ljudsko telo nekonzistentno, pa bi delovi ostrice dobili razlicitu cvrstinu, te da bi doslo do deformacije ostrice itd... Verovatno su neki majstori koristili krv (mada i tu pre volovsku nego ljudsku), a i verovatno su majstori pravili prezentacije svojih novih proizvoda tako sto bi ubili nekog roba (nalik onima sa dusecima), tako da je mit verovatno nastao odatle.

To ima jako mnogo smisla.
Gde bi pa proboli coveka da okale celik? Kroz stomak? jok, tu ima likvora, vazduha u crevima, feces... jako problematicno.
Kroz grudi? Pluca su puna vazduha, brojne hrskavicave strukture mogu samo da skode vise nego da koriste, ako tako vreo i jos relativno mek celik udari u kicmeni stub, bye-bye vrhu maca i tako dalje...
Kroz vrat ista prica, zbog ezofagusa, onda bogate limfne vaskularizacije vrata, stitna zlezda...jako nekonsistentna sredina.

mnogo je verovatnije da su ka lepo kalili krvlju ili najobicnijom vodom, a onda radili demonstracije an robovima budzovanima koji se na to loze, i daju pare da im se taj mac, jel', napravi

[Awakened]

Nego, mene zanima da li radi ona fora iz Konana kad njegov cale kali mac u snegu?

[Ota]

Nego, mene zanima da li radi ona fora iz Konana kad njegov cale kali mac u snegu?

Da, video sam lika u americi koji tako kuje - cak je verovatno najbolji "kovac" tamo. Mislim da se preziva Angus ili tako nesto.

[Dr. Nick Riviera MD]

Nekada davno (secanje baguje) sam naleteo na dosta argumenata protiv te price o robovima. Te da je ljudsko telo nekonzistentno, pa bi delovi ostrice dobili razlicitu cvrstinu, te da bi doslo do deformacije ostrice itd... Verovatno su neki majstori koristili krv (mada i tu pre volovsku nego ljudsku), a i verovatno su majstori pravili prezentacije svojih novih proizvoda tako sto bi ubili nekog roba (nalik onima sa dusecima), tako da je mit verovatno nastao odatle.

To ima jako mnogo smisla.
Gde bi pa proboli coveka da okale celik? Kroz stomak? jok, tu ima likvora, vazduha u crevima, feces... jako problematicno.
Kroz grudi? Pluca su puna vazduha, brojne hrskavicave strukture mogu samo da skode vise nego da koriste, ako tako vreo i jos relativno mek celik udari u kicmeni stub, bye-bye vrhu maca i tako dalje...
Kroz vrat ista prica, zbog ezofagusa, onda bogate limfne vaskularizacije vrata, stitna zlezda...jako nekonsistentna sredina.

mnogo je verovatnije da su ka lepo kalili krvlju ili najobicnijom vodom, a onda radili demonstracije an robovima budzovanima koji se na to loze, i daju pare da im se taj mac, jel', napravi

Slazem se sa Kosanovicem,previse nereda i previse varijabli je tu ukljuceno.A sto krvavija demonstracija to vise love :D

Kaljenje krvlju mi ne zvuci lose narocito zbog gusto napakovanih molekula gvozdja koji su vezani za hemoglobin u krvi ali ne znam koliki uticaj to realno moze da ima