There are two amazing scientific and technological miracles about Jian Qin:
The first example is that archaeologists discovered a "memory alloy sword" when cleaning the first pit 1 1 of the Terracotta Warriors and Horses of Qin Shihuang. This bronze sword was bent by a statue of150kg clay figurine, and the bending degree exceeded 45 degrees. When people removed the clay figurine, an amazing miracle appeared: the narrow and thin bronze sword bounced up instantly and recovered naturally.
The "shape memory alloy" that contemporary metallurgists dream of actually appeared in the pit of Qin figurines more than 2,200 years ago, which can not but make people sincerely admire the miracle created by their ancestors.
The second example is 1994, and a batch of bronze swords with eight facets were found in the second pit of the Terracotta Warriors and Horses of Qin Shihuang. Archaeologists measured with vernier calipers and found that the errors of these eight facets were less than one hair, and the bronze sword 19 had been unearthed.
These bronze swords are compact in structure, smooth in body, fine in grinding grain on the blade and integrated in texture. They have been sleeping in the loess for more than 2200 years, and they are still as bright as new and extremely sharp when unearthed. After testing, the researchers found that the surface of the sword has a layer of chromium salt compound with a thickness of 10 micron.
This discovery immediately caused a sensation in the world, because this "chromium salt oxidation" treatment method is an advanced technology that only appeared in modern times. Germany invented it in 1937 and the United States invented it in 1950, and applied for a patent. In fact, as early as the Spring and Autumn Period and the Warring States Period, China people had mastered this advanced technology.
Looking back on the development of bronze swords in the Central Plains, the body of the sword is getting longer and longer. At first, the sword was only twenty or thirty centimeters long; In the Spring and Autumn Period and the Warring States Period, the length generally reached about 50~60 cm; In the late Warring States period, some swords exceeded 70 cm, and the longest reached 75 cm or 76 cm. In the Qin Dynasty, the length of Jian Qin in Guanzhong reached a new level, exceeding 80 cm, and the longest reached nearly 95 cm.
The primary role of bronze sword in Wushu is to kill the enemy and penetrate the opponent's armor, while splitting and pulling is only an auxiliary role. Jian Qin, who is nearly 30 centimeters longer than his opponent's sword, is obviously more likely to stab his opponent in battle, which may be the main reason why Jian Qin has become longer. However, this is a bronze sword after all. What methods did the Qin people use to make the sword not easy to break?
In the bronze age, the key to casting swords was how much tin was added to copper during smelting. Without tin, the sword is too soft. Tin is harder than a sword, but it breaks easily. Jian Qin's chemical quantitative analysis shows that its copper-tin ratio makes the hardness and toughness of bronze sword combine just right. As the last peak of bronze sword casting technology, Jian Qin's length, hardness and toughness have reached an almost perfect combination, and its attack performance has been greatly improved.
Yuan Zeng, the first team leader of the Qin Ling Archaeological Team, said: We have distributed the Qin Ling Jian to the Chinese Academy of Geological Sciences, China Nonferrous Metals Research Institute, Shanghai Smelter and other units, and carried out laser micro-spectroscopy, electron probe, X-ray fluorescence detection and chemical quantitative analysis. It is found that there is a dense chromium oxide net on the sword surface, which is about 10 micron thick, equivalent to one tenth of the thickness of a newspaper, and the chromium content is 0.6% to 2%.
It is with this gray chromium-containing protective layer that it plays a powerful role in rust prevention and corrosion protection, which is higher than the corrosion resistance of Wu Hejian's surface after vulcanization.
Qin bronze sword is not only long, but also very sharp. Some swords were unearthed without rust, as clean as new and with sharp blades. After testing, it can scrape through 18 paper at one time. The surface of these swords is grayish yellow, with fine texture and no trachoma. The surface of the swords has been finely filed and polished, so it is extremely smooth and bright.
Qin bamboo slips have a special body and a long hilt. Most of the bronze swords unearthed in pits 1 and 2 of Qin Terracotta Warriors and Horses are about17 ~ 20cm in length. According to Jian Qin's length, weight and practical function of attack and defense, Qin Jian is mostly used with both hands (two-handed swords can sometimes be used with one hand); A few with shorter stems may be one-handed swords.