How about the ancient Chinese steelmaking technology

China's ancient steelmaking technology was invented in the late Spring and Autumn period. By the pre-Qin to the late Western Han Dynasty, the main steel-making process is a block of iron carburization method; by the Han Dynasty to the Ming and Qing Dynasties, the main steel frying method and the method of steel filling, followed by a hundred refined steel method and frying iron carburization method, Han Wei and North and South Dynasties, there is a "cast iron decarburized steel", the Han Dynasty and the crucible of the steelmaking method. Fried steel process mainly produces general malleable iron (including steel and cooked iron), the steel process mainly produces higher carbon edge steel, steel is a hundred refined steel is the ordinary fried steel reprocessing. "Cast iron decarburized steel" and fried iron carburized steel process will be introduced in Chapter 5, here mainly discuss the other five.

One, the invention of steelmaking and the use of block iron carburized steel

Today in the archaeological excavations in China's earliest steel artifacts is the 1976 Changsha Yangjiashan unearthed late Spring and Autumn period steel sword, sword length of 38.4 cm, body length of 30.6 cm. After analysis, the carbon content is about the same as medium-carbon steel, the organization is uniform and dense. Changsha railroad east station construction project cultural relics excavation team: "Changsha new discovery of late spring and autumn period of steel sword and iron", "cultural relics" 1978, no. 10. It can be known that China's ancient steelmaking was invented in the late Spring and Autumn period at the latest. After the middle and late Warring States period, steelmaking in many places in the north and south of China have developed rapidly, and first in the south of the state of Chu reached a high level. The Historical Records And#8226;; Fan Ju biography" cloud: Qin Zhao Wang sighed before the dynasty, said: "I heard that the iron sword of chu and advocate you clumsy." Xunzi And#8226;; discussing the military" also cloud: "WAN Vantage Iron Bucket, miserable as an insect." "Wan" in today's Nanyang. "Vantage" that is, steel, "釶釶" that is, spears. Yang Kyung's note to Xunzi And#8226;s "Discussion of Soldiers". The sharp "iron swords" and "iron spears" were obviously made of steel. Korea in the Central Plains also made many sharp weapons, and the "Strategies of the Warring States Period And#8226;; Han Ce I" says: "The swords and halberds of the Han pawns are all out of Heshan, Tangxi, Moyang, Hepo (shoulder), Dengshi, Wanyuanfeng, Longyi, and Tai'a. They break horses and oxen on land and hit the water with their spears, but they are also made of steel. All land break horses and cattle, water hit swan and geese, when the enemy that is chopped." These sharp swords and halberds are generally considered by later scholars to be made of steel. Among them are the Heshan (in present-day Xin County), Tangxi (in Xiping County), Hebo (in Xiping County), and Fengchi (in Xingyang County), which are cited in the Historical Records of the People's Republic of China (史记And#8226；；Su Qin Lianzhuan), where Xu Guang said, "There is a Fengchi in Xingyang. Suoyin: "Wan people in Feng Chi casting sword, so the name Wan Feng", "Deng state workers casting swords, because of the name Deng Shi." Deng State is southeast of Luohe City in present-day Henan Province. Ancient iron smelting sites have been found in Longquan and Tai'a (both in Xiping County, now under the jurisdiction of the Maoyang Iron and Steel Works). Dong Wen'an, "A Preliminary Examination of the Origins of the Ten Great Treasured Swords of Korea," Papers from the National Colloquium on the History of Metallurgy, 1989, Maoyang. Moyang is in present-day Xichuan County, Henan Province. In 1965, 15 steel swords, 19 spears, 12 halberds, etc. were unearthed from Tomb No. 44 in Yixian County, Hebei Province; six of the bladed weapons were analyzed, and except for one that was made of block-refined iron, the other five were made of steel. Beijing Iron and Steel Institute, Pressure Processing: Preliminary Report on the Metallurgical Examination of Iron Weapons in Tomb No. 44 of Yanxiadu, Yixian County. Archaeology, 1975, No. 4, excavation report in the same issue of the same period, Hebei Yixian Yan Shidu No. 44 tomb excavation brief. It shows that the steel-making art of Yan in the north at that time had also been developed.

Early human smelting of steel is generally in the low-temperature reduction smelting and then carburization, the whole process is divided into two steps: the first step from the first ore smelting block of iron, the second step from the block of iron carburization into steel. This carburization process should be constantly folded and forged to help the diffusion of carbon. The steel thus obtained will be called block iron carburized steel. Weapons such as the Yanshidu steel sword are made of this steel. If properly controlled, there is no second step, but a reduction smelting into steel, this steel is called block smelting steel or natural steel. The strength and hardness of these two types of steel are higher than the block smelting iron. The disadvantages are: (1) the carbon content is generally lower. (2) carbon distribution is often not uniform. (3) The steel contains inclusions tend to be more. (4) Lower productivity. In the Central Plains cultural area, this steel-making process was used until the middle of the Western Han Dynasty, after which it was gradually replaced by the invention and development of steel frying. Mancheng Han tombs unearthed Liu Sheng sword and wrong gold book knife and so on are made of iron carburized steel by the block, its inclusions have been less than Yanshidu steel sword, the organization is also more uniform and dense. This steel is mainly used to make swords and other edged weapons, agriculture and handicrafts in the use of very little.

Two, fried steel and its process operation

Fried steel process is a semi-liquid smelting. It takes pig iron as raw material, the pig iron is heated to liquid semi-liquid state, the use of oxygen in the blast to make the pig iron decarburized to the range of composition of steel and cooked iron. The smelting process should be constantly stirring the metal. Anciently known as "擣 just", before the 1950s, Xi called the fried iron, fried "cooked iron".

(A) the invention and development of fried steel

China's ancient fried steel technology was invented in the late Western Han Dynasty, now see the earlier relics are: Gongxian Tiesheng ditch, Nanyang Wafangzhuang, Xin'an Ludeng village and other smelting and casting of iron sites unearthed in the Han Dynasty fried steel furnace, as well as Tiesheng ditch unearthed iron, iron hoe residue, iron husk 14 pieces of fried refining products. Tiesheng ditch fried steel furnace is dug out to the underground fou-shaped pit, coated with refractory mud, 0.37 meters long, 0.28 meters wide, the residual height of 0.15 meters, the furnace wall has been burned into black, the residual remains of an iron block. Henan Provincial Culture Bureau Cultural Relics Task Force: Gongxian Tieshenggou, Cultural Relics Publishing House, 1962 edition, Zhao Qingyun, etc.: Gongxian Tieshenggou Han Dynasty Smelting and Casting Sites Re-examined, Archaeology Journal, 1985, No. 2. China's ancient records on steel frying were first seen in the middle and late Eastern Han Dynasty. Taiping Jing" Volume 72 cloud: "now the military division soldiers, ominous weapon also ...... have urgent is after making the engineer to hit the stone, seeking which iron, burning and smelting, so that into the water, is after making the good work of ten thousand forging, is into the Mo Xie Ye?" This "Mo Xie" refers to sharp weapons. "Burning and smelting" and other three sentences refers to the whole process of frying and refining and its production. The Taiping Jing is a Taoist work, which basically maintains the original appearance of the middle and late Eastern Han Dynasty.

The invention of steel frying rapidly changed the use of malleable iron in our society. 1952-1953, 225 tombs were excavated in the middle of the Western Han Dynasty to the late Eastern Han Dynasty in Luoyang Yakigou, and 116 iron and steel knives, 33 swords, 5 spears, and 4 axes were unearthed; and there were only 7 copper knives (ceremonial weapons), 1 spear, and no swords among the bronze bladed weapons. Institute of Archaeology, Chinese Academy of Sciences, Luoyang Yaogou Han Tomb, Science Press, 1959. 217 Han tombs of the same period were excavated in the western suburbs of Luoyang in 1957-1958, and 52 steel knives, 58 swords, 1 halberd, and 1 axe were unearthed; there was only 1 bronze weapon edged with a knife. The Luoyang Excavation Team of the Institute of Archaeology of the Chinese Academy of Sciences: "Report on the Excavation of Han Tombs in the Western Suburbs of Luoyang", Journal of Archaeology, No. 2, 1963. After the middle of the Western Han Dynasty, in addition to crossbows and arrowheads still use more bronze, other weapons edged weapons have been made of iron and steel, the raw material is obviously fried steel. In this way, iron and steel objects in agriculture, handicrafts, military three completely replaced the dominant position of bronze and wood and stone.

Steel frying process in China by the Han Dynasty has been used until the Ming and Qing dynasties. The relevant records in the Tang "Xiahou Yang counting scripture", Song Su Song "Tu Jing Ben Cao", Ming Tang Shunzhi "martial arts before the editing", Zhao Changji "Divine Artifacts Spectrum", Zhu Guozhen "Chung Block Siu Pin", the Qing Dynasty Qu Dajun "Guangdong Xinyi" and other books can be seen. Guangdong New Words" Volume 1.5 "goods language And#8226;; Iron" said: "the fried iron is to pig iron into the furnace, the fire burned through the red and then out and put on the anvil, a person tongs, two or three people hammered, beside more than ten children fan, the children will be singing constantly, and then can be refined and cooked and for the wok also. " Published in 1920 Geng Buchan "Shanxi Mining Zhiliu" Volume V said: "will be refined out of pig iron plus coal burning, so that the iron juice, cold and then placed in the frying furnace fried, that is, mature iron." In the 1980s, Hunan Youxian and other places still use this method of production.

Steel frying process has the following advantages: (1) as raw material pig iron is easy to obtain, it expands the source of raw materials. (2) smelting in a semi-liquid state, decarburization reflects a more rapid, higher productivity. (3) composition range is wider. According to the analysis, iron raw ditch out of a fried steel material containing carbon 1.288%, silicon 0.231%, manganese 0.017%, phosphorus 0.024%, sulfur 0.022%, and over *** analysis of high-carbon steel is comparable to the other composition: carbon 0.048%, silicon 2.35%, manganese trace, phosphorus 0.154%, sulfur 0.012%, and today's cooked iron is comparable. Li Zong: "Exploration of the development of iron and steel smelting technology in pre-feudal China", Archaeology Journal, 1975, No. 2. Today's scholars often refining pig iron first, and then by the pig iron steelmaking process called two-step smelting, then the emergence of fried steel is the two-step smelting of a certain point in the history of metallurgy in the world occupies an important position. In Europe, and fried steel similar process in about the sixteenth and seventeenth centuries before the emergence of the entire Middle Ages is dominated by the natural steel method and block iron carburization method. Its supply of malleable iron was therefore inadequate for a long time, and this naturally had an effect on the progress of society.

Steel frying method is the basic process of China's ancient malleable iron production, its main uses are three: (1) the production of general forgings. From the Han to the Ming and Qing Dynasties, China's general forgings, including production tools, household utensils and bladed weapons in the forgings are about fried steel and its reprocessing products made. (2) Used as raw material for steel refining. (3) Used as raw materials for steel filling.

(B) the process of steel frying operation

China's steel frying there are three different types of technology:

(1) single-room type frying. The basic feature is that the metal melting and fuel combustion in a chamber. This method was invented earlier, used for a longer period of time, the aforementioned Gongxian Tiesheng ditch, Nanyang Wafangzhuang, Xin'an Ludeng village of the Han Dynasty frying and refining method all belong to this type. Fifties of this century, Henan, Shanxi and other places have been popular in a "ground furnace", the furnace below the ground, such as the shape of a percussion or straight cylinder, the mouth of the furnace and the ground straight. Smelting first put charcoal (coal), then put pig iron, pig iron need to be broken, and then covered with coal on top. After that, the fire is lit, the air is fed and the furnace opening is closed. When the pig iron is close to melting, the opening of the furnace is opened, and the metal is constantly stirred with iron or wooden sticks. With the frying of the proceeding, the carbon is constantly reduced, the melting point of the metal rises, it will be bonded into a spongy solid block, and then clamped out of the hammering, exclude inclusions, and give a certain shape, is to fry the product. Some provinces in the south and a popular "table furnace", built on a special stove, and has a larger heating and frying space. Wenzhou region of the frying furnace made of brick, like a chicken coop, the bottom of the furnace is close to the ground plane, frying room is an irregular rectangular space, the front of the furnace is set up a furnace mouth, where the feed, operation, out of the steel, and thus the escape of waste gas; blast from the bottom of the furnace into the bottom, and the bottom of the furnace right in the middle; operation method and the ground furnace is similar. Hunan Youxian also has a similar furnace Wenzhou frying process in 1977 survey, Youxian frying steel Department in 1980 survey, are in production. The advantages of a single room type fried refining equipment is simple, the disadvantage is that because of direct contact between the metal and the fuel, contains harmful inclusions tend to be more.

(2) double chamber type frying, or called reflecting furnace (inverted flame furnace) frying. The basic characteristics of fuel combustion and metal melting each occupies an independent space. Fuel combustion produces a high-temperature flame flow over the fire wall (fire road) into the melting room, and heating the metal, and then discharged from the furnace door or specially set up chimney. Since the metal does not come into direct contact with the fuel, the possibility of harmful impurities such as phosphorus and sulfur entering it is reduced. The invention of this steelmaking method time to be examined. 1935 published "China Industrial Journal (Hunan Province)" said the seventh: "Hunan Province, Shaoyang, Wugang, Xinning, Xiangtan County, the local method of steelmaking, from a long time ago. Shaoyang formerly known as Baoqing, the steel produced, called 'Baoqing large steel'. Shaoyang near the Wugang, Xinning products, are concentrated in Shaoyang, the industry is also 'Baoqing large steel' name. Early Qing dynasty, Baoqing big steel, extremely prestigious, and the production of more, the first Shaoyang Nanxiang." Because of the Baoqing big steel is the inverted flame furnace refining, by this record, the invention of the reflecting furnace should be in the early Qing dynasty before the age of invention. Today in archaeological excavations in the earliest inverted flame kiln is the Nanjing eye incense temple found in the early years of Ming Hongwu built a row of six glazed kilns. Nanjing Museum: "Ming dynasty Nanjing Jubao mountain glazed kiln", "cultural relics" 1960, No. 2. 1958, this inverted-flame furnace steelmaking in many places in the north and south of China have been used. The furnace in Lushan, Henan Province, is relatively simple, with two chambers close to each other, all built below ground level, with the blast entering from the lower part of the combustion chamber, and then from the top of the frying chamber into the frying chamber. Xi'an's furnace is another kind, frying room built below the ground, the combustion chamber built above the ground, the two chambers superimposed on the top and bottom, the bottom of the combustion chamber is facing the center of the frying room, the wind from the combustion chamber of the upper drum into the combustion chamber, and then by the bottom of the combustion chamber of the mouth of the fire directly into the frying room. The top of the combustion chamber is closed with a cover plate. Science and Technology Health Publishing House: "low-temperature steelmaking clay method," the sixth part of the "simplest reflex furnace steelmaking," 1958 edition.

(3) tandem frying. The only relevant records are found in the Ming Dynasty Song Yingxing "Tian Gong Kai Wu" Volume 1.4 "Iron" article: "If you make cooked iron, the raw iron outflow, connected to a few feet, a few inches lower, build a pond, a short wall against it. Iron into the pond, several people holding willow sticks lined up on the wall. First to dirty tide mud dry. Pounding sieve fine Luo such as noodles, a person sprinting hand sprinkle And#63083;;;, the crowd of willow stick stirring, instant frying mature iron. The willow stick each fried once burned folded two or three inches, and then use it again and more. Fry over a little cold, or have on the pond chopping and scratching into a square, or put forward the swinging vertebrae round after the goods. If the Liuyang metallurgy, do not know out of this also." This "dirty tide mud" is likely to be slag melt. Here talked about the whole process of tandem frying. The advantage of this method is that pig iron out of the furnace directly into the square pond frying, eliminating the process of reheating pig iron, thus saving time and reducing costs.

The need for special attention is the ancient "cooked iron" term, Song Yingxing in the above quotes have been mentioned twice in other ancient literature is also often seen, the meaning of the modern cooked iron is different. The ancients did not have the concept of carbon content, the difference between pig iron, steel, cooked iron is mainly based on its performance, hard and brittle for the "raw", can be wrought for the "cooked", the nature of the strong for steel. Because the frying process is carried out in a semi-liquid state, slag iron separation is more difficult, the product contains inclusions are often more, even if the carbon content is higher, but its nature is not just, can only be called "cooked iron". Yuan pseudo-compiled "rough talk" volume "occasional notes" article cloud: "the ground ulcer oil and such as mud, color gold, gas fishy, soft iron burning red cast two or three times, just can cut jade." This "soft iron" is "cooked iron". Su Gong "Tang Materia Medica" cloud: "soft iron, that is, cooked iron." This is the material properties to distinguish between steel and "cooked iron". Su Song "Tu Jing Ben Cao" cloud: "the first refining to go to the mine, used to cast diarrhea objects for the pig iron, and then three pin pat, can be thinly sliced for the lock of the iron, also known as ripe iron." Su Gong "Tang Materia Medica", Su Song "Tu Jing Materia Medica" are quoted from the "Materia Medica Compendium" Volume VIII "gold and stone;; iron". This is to distinguish between steel and iron by material properties and smelting process. Tiangongkaiwu" Volume 14 "iron" article: "Where iron is raw and cooked, out of the oven is not fried as raw, both fried is cooked." Smelting process alone here as a distinction between steel, iron standards. Some scholars regard the ancient "ripe iron" and modern ripe iron is equivalent to the "Tiangong Kaiwu" volume 14 contained in the frying of "ripe iron" process.