At present, main attention is paid to alloying of steels to improve significantly their mechanical and elastic properties. As known, the ancient damascus steel was just plain carbon steel with extremely high mechanical and elastic properties. Note, the main attention should be paid to new ways of heat treatment.
Ancient smiths had some "Know - How" which are not yet clearly known at present.
Dear Nikolai, I think the key point on the misty description of the Damascus Steel lies on the following historical aspects: quated from WIKI:
'' The original Damascus steel or wootz was imported from India to the Middle East. Due to the distance of trade for this steel, a sufficiently lengthy disruption of the trade routes could have ended the production of Damascus steel and eventually led to the loss of the technique in India. As well, the need for key trace impurities of tungsten or vanadium within the materials needed for production of the steel may be absent if this material was acquired from different production regions or smelted from ores lacking these key trace elements.The technique for controlled thermal cycling after the initial forging at a specific temperature could also have been lost, thereby preventing the final damask pattern in the steel from occurring.''
''The discovery of carbon nanotubes in the Damascus steel's composition supports this hypothesis, since the precipitation of carbon nanotubes probably resulted from a specific process that may be difficult to replicate should the production technique or raw materials used be significantly altered''
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Dear Tarik,
Thanks for your nice comments. I think the key is in "The technique for controlled thermal cycling after the initial forging at a specific temperature...."
Please, see "An explanation of possible Damascus Steel manufacturing based on duration of transient nucleate boiling process" in my RG contribution.
I Thank you Nikolai. I would be interested to see how did you menage by transient nucleation boiling process such as complicated thermo- mechanical treatment, at end of which the grain structure looks like a bundle of stretched fibers along the knives' longitudinal axes.?
During the transient nucleate boiling process the surface temperature maintains at the level of boiling point, slightly exceeding it. When quenching high carbon steel in water, martensite transformation can be delayed completely since Ms < = 100oC. There is a great opportunity here for low temperature thermo = mechanical treatment if duration of boiling process is known. Probably, many times heating-cooling and forging can create special structure. More information one can find in: N.I.Kobasko, Duration of the transient nucleate boiling process and its use for the development of new technologies, In a Book "Film and Nucleate Boiling Processes" , ASTM International , West Conshohocken, USA, 2012, pp. 103 - 125. Thank you Tarik for interesting question.
Dear Nikolai, what did you described to me now, it is a very special process, which you have been successfully pursuing in obtaining almost completely martensitic structure? That means supersaturated metastable ferritic structure having tetragonal structure exposed to heavy quenching - residual- strains. If you would try little more in increasing the quenching rate by exposing it to the liquid nitrogen jet, you might have been ending up with a beautiful metallic glass of high carbon steel. This material would be visco-elastic having extraordinary mechanical properties if you could inhibit its transformation into ferrite and cementite having own microstructure. But this is nothing to do with the DAMACUS steel, but might be better then that one!
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To be more understandable, we should consider three completely different technologies.
1. When melted metal is cooled extremely fast by liquid nitrogen jet, it can produce metallic glass. There are many investigations in this field.
2. Steel is heated to austenitizing temperature, cooled very fast in water solutions with delaying martensite transformation and then very fast cooling is provided in martensite range, for example in liquid nitrogen jets. Steel is super-strengthened in this case.
3. High carbon steel is heated to austenitizing temperature, cooled very fast in water solutions with delaying martensite transformation and then process is interrupted to provide forging. Cooling and forging can be repeated many times.
The third technology can produce something similar to Damascus steel.
Interesting discussion,.
Thank you.
Dear Tarik,
I would appreciate very much if you could provide your vision on what will happen in 2050 year concerning production and processing alloy steels. Damascus steel was mentioned as a hint to show that we didn't use all processing opportunity which are hidden even in plain carbon steel. It is very important to know your opinion. Thanks for interesting discussion..
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