First, the invention of steelmaking and the use of carbon block iron carburized steel.
Today, the earliest steel artifacts discovered in archaeological excavations in China are 1976 steel swords unearthed in Yangjiashan, Changsha, which are 38.4 cm long and 30.6 cm long. After analysis, the carbon content is roughly equivalent to that of medium carbon steel, and the structure is uniform and dense. Cultural relics excavation team of Changsha East Railway Station construction project: steel swords and ironware newly discovered in Changsha in the late Spring and Autumn Period, with cultural relics number 1978,No. 10. It can be seen that the ancient steelmaking technology in China was invented at the end of the Spring and Autumn Period at the latest. After the middle and late Warring States Period, steelmaking developed rapidly in many places in the north and south of China, and reached a high level in Chu in the south at the earliest. Historical Records and # 8226; ; ; "Biography of Fan Ju" said: Wang Linchao sighed: "I have heard for a long time that Chu Tiejian is beneficial and advocates superiority." Xunzi and # 8226; ; ; The discussion of the military strategists also said: "Ten thousand shovel is as miserable as a cockroach." Wan's rule is in Nanyang today. "Giant" means steel, and "chisel" means spear. Xunzi and # 8226; ; ; "Yang Xu to the soldiers note 1. This sharp "iron sword" and "iron spear" are obviously made of steel. South Korea also made many sharp weapons in the Central Plains, such as Warring States Policy and # 8226; ; ; Han Ceyi said: "The swords, spears and halberds of the Han people all came from the famous mountains, Tangxi, Yang Mo, Hebo, Feng Wan, Long Yuan and Taiya. On land, cattle and horses are all broken, and water beats geese. When you kill the enemy, you must kill it. " These sharp halberds are generally regarded as steel by later scholars. Among them, Mingshan (now Xin County), Tangxi (Xiping County), Hebo (Xiping County), Fengchi (Xingyang County) Historical Records and # 8226; ; ; "Biography of Su Qin quoted Guangxu as saying that there is a phoenix pool in Xingyang". Suoyin: "Ten thousand people cast swords in Fengchi, hence the name", and "Deng Guogong cast swords, hence the name". "Deng Guo is in the southeast of Luohe City, Henan Province. Ancient iron smelting sites were discovered in Longquan and Tai 'an (both in Xiping County, now under the jurisdiction of Wuyang Iron and Steel Plant). Dong Wen 'an: A preliminary study on the origin of North Korea's top ten swords, paper of the national symposium on metallurgical history, Wuyang, 1989. Yang Mo is in today's Xichuan County, Henan Province. 1965, steel swords 15, spears 19, halberds 12 were unearthed from No.44 tomb in Xiaxiadu, Yixian, Hebei. Six of them are analyzed. Except 1, the others are all made of steel. Pressure processing major of Beijing Institute of Iron and Steel: Preliminary report on metallographic investigation of iron ware in No.44 tomb in Yanxiadu, Yixian County. Archaeology, No.4, 1975. For the excavation report, see the same issue of Excavation Briefing of No.44 Tomb Yanxiadu in Yixian County, Hebei Province. It shows that the steelmaking technology of the northern Yan state also developed at that time.
The steel smelted in the early days of mankind is generally carburized after low-temperature reduction smelting. The whole process is divided into two steps: the first step is smelting iron from ore, and the second step is carburizing steel from iron. In this carburizing process, continuous folding and forging are needed to help the diffusion of carbon. The steel thus obtained is called block iron carburized steel. The steel swords and other weapons of Yanxiadu are made of this kind of steel. If properly controlled, some steel is reduced and smelted at one time without the second step, which is called block steelmaking or natural steel. The strength and hardness of these two steels are higher than that of block ironmaking. Its disadvantage is that (1) carbon content is generally low. (2) Carbon distribution is often uneven. (3) Steel often contains more inclusions. (4) Low productivity. In the Central Plains Cultural District, this steelmaking process was used until the middle of the Western Han Dynasty, and was gradually replaced by the invention and development of fried steel. Liu Shengjian and Cuojin Shudao unearthed from the Han Tomb in Mancheng are made of iron carburized steel with few inclusions, and their structures are more uniform and dense than those of Yan Xiadu's steel sword. This kind of steel is mainly used to make swords and other weapons, but rarely used in agriculture and handicrafts.
Second, stir-frying steel and its technological operation
The steel frying process is semi-liquid melting. It takes pig iron as raw material, heats it to liquid and semi-liquid, and decarburizes it to the composition range of steel and wrought iron with oxygen in blast. In the process of smelting, the metal should be constantly stirred. In ancient times, it was called "Daogang". Before the 1950s, it was used to be called "fried iron fried" wrought iron.
(A) the invention and development of fried steel
China's ancient steel explosion technology was invented in the middle and late Western Han Dynasty. Today, the earliest relics are: the Han Dynasty steel blast furnace unearthed from iron smelting sites such as Tieshenggou in Gongxian County, Wafangzhuang in Nanyang and Denggu Village in Xin 'an, and the fried products such as iron blocks, residual iron hoes and iron pans unearthed in Tieshenggou 14 pieces. Tieshenggou steel frying furnace is a small pit dug underground, the surface of which is coated with refractory mud, with a length of 0.37 m, a width of 0.28 m and a residual height of 0.15 m. The furnace wall has been burnt black, and an iron block remains inside. Cultural Relics Team of Henan Provincial Cultural Bureau: Tieshenggou, Gongxian County, Cultural Relics Publishing House, 1962, et al.: Re-discussion on the smelting and casting site of Tieshenggou in Han Dynasty, Journal of Archaeology, No.2, 1985. In ancient China, the record of steel frying began in the late East Hanzhong. "Taiping Jing" Volume 72 says: "Today's strategists and soldiers are also ominous tools ... If they are in a hurry, they will ask engineers to knock on the stone, ask for iron in it, burn it and turn it into water. Then they will let good workers forge it and it will become Mo Xie. " This "Mo Xie" refers to a sharp weapon. The words "burning and melting" refer to the whole process of frying and making the device. The Taoist work Taiping Jing basically kept its original appearance in the middle and late Eastern Han Dynasty.
The invention of fried steel quickly changed the use of malleable cast iron in our society. 1952- 1953, 225 tombs from the middle Western Han Dynasty to the late Eastern Han Dynasty were excavated in Shaogou, Luoyang, and 1 16 steel knives, 33 swords, 5 spears and 4 axes were unearthed. Among the bronze weapon blades, there are only seven bronze knives (ceremonial weapons), 1 spear, and no sword. Institute of Archaeology, China Academy of Sciences: Shaogou Han Tomb, Science Press, 1959. 1 957-1 958,217 Han tombs were excavated in the western suburbs of Luoyang at the same time, and 52 steel knives, 58 swords, halberds1and axes1were unearthed. The bronze weapon is only 1 knife. Luoyang Excavation Team, Institute of Archaeology, China Academy of Sciences: Excavation Report of Han Tomb in the Western Suburb of Luoyang, Journal of Archaeology, No.2, 1963. After the mid-Western Han Dynasty, except for crossbows and arrows, bronze was still widely used. Most of the blades of other weapons were made of steel, and their raw materials were obviously fried steel. In this way, steel objects completely replaced bronze and wood and stone in agriculture, handicrafts and military.
From the Han Dynasty to the Ming and Qing Dynasties, China has been using steel frying technology. There are related records in Xiahou Yang suan Jing in Tang Dynasty, Illustrated Materia Medica by Su Song in Song Dynasty, Qian Bian by Wu Bian in Ming Dynasty, Artifact Spectrum by Zhao Changji, Sketch of Chong Zhuang by Zhu Guozhen and Guangdong Xinyu by Qu Dajun in Qing Dynasty. Guangdong New Language, Volume 15, Pinyu and # 8226; ; ; The article "Iron" said: "Iron is fried with pig iron balls, and when it is red, it is placed on the anvil. One person pinched, two or three people hammered, and more than a dozen boys fanned. Boys will sing nonstop, and then they can be cooked into woks. Volume 5 of Notes on Mining in Gengshan West published by 1920 says: "Add refined pig iron into pulverized coal and burn it into iron juice, then cool it and put it into a blast furnace, which is the wrought iron. "In the 1980s, this method was still used in Youxian County, Hunan Province and other places.
The advantages of steel frying process are: (1) raw pig iron is easily available, which expands the source of raw materials. (2) Melting is carried out in semi-liquid state, so the decarbonization reaction is faster and the productivity is higher. (3) Wide range of ingredients. According to the analysis, a piece of fried steel from Tieshenggou contains carbon 1.288%, silicon 0.23 1%, manganese 0.0 17%, phosphorus 0.024% and sulfur 0.022%, which is equivalent to hypereutectoid steel and high carbon steel. The other component is: carbon 0.048%, silicon 2.35%, trace manganese, phosphorus 0. 154% and sulfur 0.0 12%, which is equivalent to the current wrought iron. Jong Li: Discussion on the Technical Development of iron and steel smelting in the Early Feudal Society of China, Journal of Archaeology No.2, 1975. At present, scholars often refer to the process of smelting pig iron first and then steelmaking with pig iron as two-step smelting, so the appearance of steel explosion is a certain point of two-step smelting and occupies an important position in the history of metallurgy in the world. In Europe, similar steel frying processes only appeared in 16 and 17 centuries, and natural steel method and block iron carburizing method dominated the whole middle ages. Therefore, the supply of malleable cast iron is insufficient for a long time, which naturally affects social progress.
The steel stir-frying method is the basic process for producing malleable cast iron in ancient China, and its main uses are: (1) making general forgings. From the Han Dynasty to the Ming and Qing Dynasties, the general forgings in China, including those in production tools, household appliances and weapons, were all made of fried steel and its reprocessed products. (2) Used as raw material for steelmaking. (3) Used as raw material for pouring steel.
(2) Technological operation of steel stir-frying
There are three main kinds of steel frying processes in China:
(1) single-chamber frying. The basic feature is that metal melting and fuel combustion are carried out in the same furnace. This method was invented earlier and used for a long time. The Han dynasty frying methods mentioned above in Tieshenggou, Wafangzhuang and Denggu Village of Gongxian County all belong to this category. In 1950s, a kind of "ground furnace" was popular in Henan and Shanxi, which was built below the ground, like a bucket or a straight tube, and the furnace mouth was in a straight line with the ground. When smelting, put charcoal (coal) first, then put iron. Pig iron needs to be crushed and covered with pulverized coal. Then ignite, blow, and close the furnace mouth. When pig iron is close to melting, open the furnace mouth and stir the metal with iron bars or wooden sticks. With the progress of frying, the carbon content decreases and the melting point of metal increases, and then it is bonded into a sponge-like solid block, and then hammered to remove impurities and make it have a certain shape. This is the fried product. In some southern provinces, there was a popular "stove", which was built on a special stove and had a lot of room for heating and frying. The frying furnace in Wenzhou area is made of brick, which looks like a chicken coop, and the bottom is close to the ground level. Real estate speculation is an irregular rectangular space. There is a furnace mouth in front of the furnace, where materials are fed, operated and discharged, and waste gas escapes. The blast enters from the bottom of the furnace, and it is right in the center of the bottom; The operation method is similar to the ground furnace. There is a similar stove in Youxian County, Hunan Province, and 1977 was investigated by Wenzhou Fried Technology Department, and 1980 was investigated by Youxian Fried Steel Department, which were all in production that year. The advantage of single-chamber frying is simple equipment, but the disadvantage is that there are often many harmful inclusions because of the direct contact between metal and fuel.
(2) Double-chamber frying, or reverberatory furnace (inverted flame furnace) frying. The basic feature is that fuel combustion and metal melting each occupy an independent space. The high-temperature flame flow generated by fuel combustion enters the smelting chamber over the fire wall (fire channel), heats the metal, and then is discharged from the furnace door or specially set chimney. Because its metal is not in direct contact with fuel, the possibility of harmful impurities phosphorus and sulfur entering it is reduced. The invention time of this steelmaking method remains to be verified. The seventh edition of China Industrial History (Hunan Province) published by 1935 said: "The indigenous steelmaking in Shaoyang, Wugang, Xinning and Xiangtan counties in Hunan Province has a long history. Shaoyang, formerly known as Baoqing, produces steel, which is called' Baoqing Big Bar Steel'. The products of Wugang and Xinning near Shaoyang are all concentrated in Shaoyang, and people in the industry are also named as' Baoqing Big Bar'. In the early Qing Dynasty, Baoqing strip steel was very famous, and it was the first to promote Shaoyang Nanxiang. " According to records, the reverberatory furnace was invented before the early Qing Dynasty, because Baoqing strip steel was smelted by inverted flame furnace. The earliest inverted flame kiln seen in today's archaeological excavation is a row of six glass kilns built in the early years of Ming Hongwu, which were discovered in Xiangmiao, Nanjing Eye. Nanjing Museum: Ming Dynasty Jubaoshan Glazed Kiln in Nanjing, Cultural Relics, No.2, 1960. 1958 this kind of inverted flame furnace steelmaking is used in many places in north and south China. The stove in Lushan, Henan Province is relatively simple, and the two rooms are almost the same, both of which are built underground. The shock wave enters from the lower part of the combustion chamber and then enters the frying chamber from the top of the frying chamber. Xi 'an's stove is another kind. The explosion chamber is built underground and the combustion chamber is built on the ground. The two rooms are stacked on top of each other. The bottom of the combustion chamber is opposite to the center of the frying chamber. The wind blows in from the upper part of the combustion chamber and then directly enters the frying chamber through the burner at the bottom of the combustion chamber. The top of the combustion chamber is closed with a cover plate. Science and technology health press: indigenous low-temperature steelmaking, part VI, the simplest reverberatory steelmaking, 1958 edition.
(3) serial bombing. Relevant records can only be found in Article 14 "Iron" of Tiangong Kaiwu in the Ming and Song Dynasties: "If wrought iron is used, when pig iron flows out, it will be connected within a few feet and dropped several inches, and the square pool will be built to offset it with short walls. Its iron flowed into the pool, and several people stood on the wall with willow branches. First dry it with dirty mud. The screen is as fine as a surface, and one person is scattered # 63083; ; ; When the willow branches are stirred, the iron will be fried at once. Its willow sticks are scalded for two or three inches every time, and it is even more powerful when used again. When the fry was a little cold, some people cut the pond into squares, or some people put forward the idea of throwing their backs around the goods. If Liuyang is all metallurgy, I don't know this. " (Figure 2-3) This "muddy mud" is probably a slagging flux. Here we talk about the whole process of serial bombing. The advantage of this method is that the pig iron directly flows into the square pool for frying after being discharged from the furnace, which saves the process of reheating the pig iron, thus saving working hours and reducing costs.
Special attention should be paid to the ancient word "wrought iron", which was mentioned twice in the above quotation in Song Dynasty and often seen in other ancient documents. Its meaning is different from modern wrought iron. The ancients had no concept of carbon content. The main basis for distinguishing pig iron, steel and wrought iron is its performance. Hard and brittle is "raw", malleable is "cooked" and strong is steel. Because the frying process is carried out in semi-liquid state, it is difficult to separate slag and iron, and the products often contain more inclusions. Even if the carbon content is high, it is not hard and can only be called "wrought iron". Yuan people forged a book called "Talking Rough" and wrote: "The oil in the ground is like mud, the color is like gold, the smell is fierce, and the soft iron burns red two or three times, just enough to cut jade." This "soft iron" is "wrought iron". Su Gong's Tang Materia Medica says: "Soft iron is also, that is, wrought iron." This is the difference between steel and "wrought iron" in material characteristics. Su Song's "Illustration of Materia Medica" said: "Those who are first smelted and used to cast diarrhea utensils are pig iron, and those who are resold can be pig iron, also known as wrought iron." Su Gong's Tang Materia Medica and Su Song's Graphic Materia Medica are both quoted from the Compendium of Materia Medica, Volume 8, Jinshi and # 8226; ; ; Iron ". This is based on the material properties and smelting process to distinguish between steel and iron. Article 14 "Iron" in Heavenly Creations: "All iron is cooked when it is born, and cooked when it is fried." Here, only the smelting process is used as the standard to distinguish steel from iron. Some scholars equate the ancient "wrought iron" with the modern wrought iron, and regard the work of frying "wrought iron" as contained in Volume XIV of Tiangong Wu Kai.