During the Two Han Dynasty, what advanced techniques were used in the production of some high-quality swords and knives?

One is the localized quenching process? Steel sword quenching process appeared in the Warring States period? After testing, Yan Xia Du site unearthed in the late Warring States steel sword, was verified to have been heated to more than 900 degrees for quenching, which is known to China's ancient earliest quenched steel? During the Western Han Dynasty, there was another development, which produced a new process of quenching only the blade of the sword? Because the blade is hardened, it has high hardness and is extremely sharp. The spine of the sword is not quenched, the hardness is lower, maintain a good toughness, not easy to break?

The second is the surface carburization process? Mancheng Liu Sheng tomb unearthed wrong gold book knife, after testing is the block of iron as raw material, by carburizing? Stacking made of low carbon steel parts? It is in the forging molding and grinding, and after the surface carburization, so that the knife's surface layer of the organization of higher carbon content, more hard? A steel sword from the same tomb was also tested after surface carburization, the surface carbon content of 0.6% or more, higher than the heart of the high-carbon layer of 0.5% to 0.6% of carbon content?

Three is a hundred refined steel process? 1974 Cangshan, Shandong Province, unearthed in the Eastern Han Dynasty steel knife, 1978 Xuzhou, Jiangsu Province, Tongshan unearthed in the Eastern Han Dynasty steel sword, are fried steel as raw materials, after repeated heating folding and forging? And the inscription on the sword, is said to be not simply the concept of the number of layers, but should represent a certain quality of craftsmanship and standards? It can be seen, the sword heating folding forging technology at that time has been developed to a new level?

In addition to the above iron smelting process, the two Han Dynasty, to identify the sword as a matter of quality of the phase of the sword art is also popular? And with the iron sword to replace the copper sword, the content of the phase sword art from the early phase of the copper sword to the phase of the iron sword? This also proves from another angle that the smelting technology of Han Dynasty has been upgraded to the theoretical level? It is because of the Han Dynasty high iron smelting technology, so that these iron weapons in the world is one of the best, almost weapons manufacturing technology up to the realm of art?