In the last issue, we said that the unearthed bronze ware Simu Wuding of Shang Dynasty represented the technical level of Chinese bronzes at that time. It ranks first in the world after 5,000 years and is a cultural treasure of the Chinese nation. From the discovery of bronze in the late Neolithic Age to the late Shang Dynasty, the smelting and casting of bronze has a history of thousands of years. Bronze smelting and bronze casting are the most advanced production departments in Shang Dynasty, and their technical level of casting bronze has reached a quite amazing height. Therefore, a large number of bronzes were left behind, leaving precious material, spiritual and cultural wealth for our future generations.
Bronze is an alloy of copper, tin and lead. Because the color of this alloy is blue-gray, the cast object is called bronze ware. According to the chemical analysis of unearthed Shang bronzes, the composition is as follows: the average copper content in the early stage was 80.83%, the tin content was 5%, and the lead content was1109%; In the later stage, the average content of copper is 85.9%, tin 1 1.7%, and lead is 0.84%. Pure copper (red copper) has a high melting point (1083 degrees Celsius). Adding 15% tin will reduce the melting point (960 degrees Celsius) and increase the hardness. Bronzes cast in Shang Dynasty were formulated and smelted according to the purpose of the objects. For example, general utensils contain less lead (lead and tin have the same function), while expensive ritual vessels, weapons and some practical tools contain more tin. Here, we can see the ancients' accurate grasp of various metal properties, and the wisdom of the ancients is really amazing.
The transition from using red bronzes to smelting and casting bronzes has gone through a stage from low to high. At the beginning of bronze smelting, tin ore or lead ore was added to copper ore. This method is still in the low stage. In Shang dynasty, pure copper was first smelted as the main raw material, and then tin and lead were added to smelt bronze and cast it into a vessel. A piece of pure copper was found in the site of copper casting workshop in Yin Ruins, with a copper content as high as 97.2%, which proved that pure copper could be smelted from malachite (copper mine) at that time, and the smelting technology had reached an advanced stage. There is "Huanglu" in Oracle Bone Inscriptions (A 1647, Jin 5 1 1), and some scholars think that "Huanglu is a good copper block." From Xia Dynasty to Shang Dynasty, the bronze wares in China made rapid progress from the primary technical stage to the advanced stage. The high-content pure copper technology once again shows the superb wisdom and skillful technology of the ancients.
Judging from the relics found, the bronze smelting equipment of Shang dynasty used crucible in the early days. A ceramic "Dakouzun" was unearthed from the site of casting copper outside Nanguan, Zhengzhou. It was mixed with grass mud inside and outside, and copper slag was stuck on the inner wall, indicating that it was a crucible for melting copper. A crucible similar to the helmet worn by ancient military commanders was found in the bronze casting site of Yin Ruins. Archaeologists call it "the general's helmet", which is also used to melt copper. It has a long handle at the bottom, which is more convenient to use than a large crucible. In particular, in order to cast a giant device like Simu Wuding, only a crucible like "General Helmet" can be used. The residual wall of the furnace was also found in the copper casting site of Beidi Ancient Market in Anyang Nursery. There is slag on the inner wall of the furnace, and charcoal and copper slag are stuck on the surface. The discovery of the crucible, an important equipment of bronze ware technology in Shang Dynasty, further proved that the wisdom and technology of ancient China ancestors had reached a quite high level.
The bronze wares of Shang Dynasty were cast with ceramic models. Before making an object, it is made of clay and dried. This is called a pottery model. Pour the molten copper into a mold for molding. A larger object should be cast separately from two, three or more pottery models, and then combined to form. From 1959 to 1960, more than 3,800 pieces of pottery sculptures were unearthed from the copper casting site of Beiyin Ruins in Nursery, Anyang. Some scholars have calculated that the casting of giant vessels like Simu Wuding requires dozens of ceramic models and crucibles (general helmets) of different sizes and shapes, and it takes at least 200 to 300 craftsmen to complete the process from copper melting to casting synthesis. The pottery casting technology adopted by the ancestors of Shang Dynasty in China has raised the bronze production technology in China to a new height, thus leaving an inexhaustible precious legacy for our descendants, and will bless our Chinese nation to stand among the nations in the world. What do you think of the wisdom and technology of our ancestors after reading the description of bronze ware technology in this article? Welcome to leave a message to discuss and continue to pay attention.