Iron weapons in the Spring and Autumn Period;
Steel swords unearthed in Yangjiashan, Changsha, Hunan Province in the late Spring and Autumn Period (around the 6th century BC)
Its carbon content is about 0.5%, which belongs to a piece of carburized steel products in ironmaking, and tempered structure has appeared. This is a heat treatment technology developed on the basis of quenching technology. 400 years before Rome.
Four chisels unearthed from the tomb of the King of Chu in Shizishan, Xuzhou (5th century BC)
After local quenching, the cutter head is hard and the cutter body is tough.
Iron weapons in the Warring States Period (4th century BC to 2nd century BC)
Steel swords used by ordinary soldiers in Yanxiadu site during the Warring States Period (4th century BC).
It consists of a high carbon layer with a carbon content of 0.5-0.6% and a low carbon layer with a carbon content of 0. 15-0.2%. Its manufacturing method is to fold iron-making sheets with different carbon contents and forge them together, and then quench them at 900 degrees to achieve the effect of combining rigidity with flexibility. There are more sorbite in the sword core and martensite in the sword body, which is tough inside and hard outside. The hardness of the blade reaches 530HV, which is much higher than that of the Roman sword 600 years later.
Spears and Arrows Unearthed in the Summer Capital of yi county in the Late Warring States Period (3rd century BC to 2nd century BC)
It is an ironmaking carburized steel product with carbon content of 0.20% and 0.25% respectively. Its internal structure is composed of ferrite and pearlite, and the spacing between pearlite sheets is wide. The results of metallographic analysis show that it is similar to the microstructure obtained by austenite air cooling normalization treatment today.
Bronze weapons in the Warring States Period (4th century BC to 2nd century BC)
Qin terracotta warriors and horses sword, ge, beryllium
The length of the sword is 9 1 cm, and there are three ridges more than 90 cm long on the sword body, which divides the slender sword body into eight sides and the sword is distributed in triple thickness. The Jian Qin test data unearthed from Terracotta Warriors and Horses is 106HRB, about 296HV. The content of external tin in Jian Qin is 17~20%, which is also at the peak of strength. It is higher than the technical index of iron sword after 400 years in Rome.
Iron weapons in Han Dynasty (2nd century BC to around A.D.)
Liu Sheng's calligraphy sword in the Han Dynasty (2nd century BC)
It is made of low carbon steel by carburizing and overlapping. After surface carburizing and local quenching, the hardness of the blade is 570HV, the hardness of the back surface is 260HV, and the hardness of the core is HV 140. It is also tough inside and firm outside. Martensite is only observed in the blade of these swords, and no quenching structure is found in the ridge of the sword. It can be seen that our ancestors had mastered the local quenching technology at the latest in the second century BC. The edge has high hardness after quenching, but the ridge still maintains good plasticity and toughness. The blade is 86.5 cm long and 3.4 cm wide. It is also layered forging carburizing and local quenching. The thickness of each layer of steel is only 0.05 ~ 0. 1 cm, which is already patterned steel. The hardness of the blade reaches 900 ~ 1 170 HV, which is harder than that of Japanese knives. The hardness of the core is 220 ~ 300 HV.
Tieshenggou Site in Western Han Dynasty (BC 1 century)
The stir-fried steel material unearthed from Tieshenggou site in the Western Han Dynasty contains carbon 1.288%, silicon 0.23 1%, manganese 0.0 17%, phosphorus 0.024% and sulfur 0.022%, and the contents of phosphorus and sulfur are reduced to the standard of modern high-quality steel (phosphorus content ≤ 0.035) At the same time, another piece of wrought iron unearthed contains carbon 0.048%, silicon 2.35%, trace manganese, phosphorus 0. 154% and sulfur 0.0 12%, which also reaches the standard of modern wrought iron. As a forging blank of iron, this wrought iron is exposed to the air in a red-hot state during the forging process, which further oxidizes and removes sulfur and phosphorus impurities. Therefore, the content of harmful substances phosphorus and sulfur in the finished steel sword in China is reduced to undetectable.
Compare the western weapons of the corresponding period.
Early West (Ancient Greece)
There were a lot of slag in ancient Greek massive ironmaking steel, and some slag reached several hundred microns. The existence of slag seriously affects the properties of iron, which is very unfavorable to toughness and strength. The softening technology of cast iron and the frying technology of steel never developed in ancient west. Block ironmaking has always been used as a weapon. Block ironmaking is the reduction of iron ore at low temperature, forming relatively pure iron particles and slag, which are spongy. Although the purity of iron particles is relatively high, in the process of impurity distribution to a large amount of slag, a lot of forging is needed to discharge slag, but forging is limited and cannot exceed twenty or thirty times. There is also the problem of metal fatigue, so the ironmaking product as a whole still contains a lot of impurities.
Later West (2nd century BC)
Iron weapon: represented by the iron sword in the tomb of Alme Devilla in Spain.
The best iron in western Europe is produced in Spain, because there are good iron ores there. Sword contains little carbon and belongs to wrought iron. Its hardness is only 95~ 135HV. Less than half that of Jian Qin. The other sword contains a little more carbon, about 0.2%~0.3%, but its hardness is only 70~ 1 17HV.
Later West (2nd century BC)
Iron weapon: represented by Celtic sword in Basel Museum.
One is the wrought iron with carbon content of 0.04 ~ 0. 1%, but the hardness reaches 160 ~ 19 1HV, and the other is relatively "well stacked" with carbon content of 0.15 ~ 0.5. However, this sword is a rare masterpiece. "It is much better than any other weapon ...". They are also "not trying to overheat" without heat treatment. The Spanish iron sword, which is famous for its good performance, has pitifully low hardness and so uneven quality.
Roman period
Gladiolus unearthed in Germany
Although the carbon content inside and outside is different, the hardness does not exceed 200HV. I can't believe it hasn't reached the level of Jian Qin. Metal heat treatment technology is actually very poor. In fact, iron swords are not quenched, and hard knives did not appear until the fourth century.