Development history and current progress of material heat treatment technology in China (2)

During the Wei and Jin Dynasties and the Southern and Northern Dynasties, China has made great breakthroughs in the mastery and application of quenching agents. Pu Yuan of the Three Kingdoms period clearly pointed out the impact of water quality on quenching. "Tai Ping Yu Lan" quoted "Pu Yuan Chuan" in the "Pu Yuan Chuan" said that Pu Yuan "melting gold special abnormal method. Knife into, said that Hanshui is blunt, not allowed to use. Lijiang is cool, it is taken in Chengdu "The impact of different water quality on quenching is undeniable, but it may be overemphasized in "Pu Yuan Chuan". Interestingly, however, after fifteen centuries, Western countries have emerged from the United States to the United Kingdom to take water quenching events. Another person who has made significant contributions to quenching technology in China is the Huai Wenwen of the Northern and Southern Dynasties. "Northern history? According to the Art Biography, "Huaiwen makes a knives, and its method burns iron and iron. It is soft and soft, and the number of places is Chenggang. With soft iron as the ridge, the bath is made of five animals, and the fat of the five animals is quenched. Thirty-seven slaps. "The fat of the five animals is animal oil, the quenching stress is small, and the tendency of deformation and cracking is small. It can also be seen that Qi Huaiwen creatively proposed a quenching process using urine. The scorpion of the five animals is salty, with strong cooling capacity and deep hardened layer. What is interesting is how to understand the "bath in the five-sacred scorpion, quenching the fat of the five animals", if it is two-liquid quenching, the quenching technology that appeared in the 6th century AD is a An important breakthrough.

The production of Chinese porcelain has a long history. It is generally believed that the representative of celadon as a porcelain was born during the Three Kingdoms period. It is made by making kaolin into a porcelain billet, incorporating an acidic oxide therein, and calcining it at a high temperature of 1000 ° C to become a porcelain. In fact, in the late Neolithic period, the ancient Chinese ancestors used porcelain clay as raw material, and the carved white pottery and printed hard pottery baked at high temperature were the foundation of the original porcelain.

After liberation, many celadon vessels from the Eastern Han Dynasty, the Three Kingdoms, and the Jin Dynasty were unearthed from the tombs throughout the north and south. From the appearance of these unearthed celadons, high-quality mineral raw materials are generally used as the green body, and the acidic oxide silica in the fetal bone is relatively increased, and the basic oxides such as calcium oxide, magnesium oxide, sodium oxide, etc. Both are relatively reduced, which leads to an increase in the firing temperature of celadon. The celadon sintered at high temperature has a high degree of vitrification of the fetal bone, and because the billet is processed finely, other impurities are rare, and a cyan glass glaze is applied on the surface thereof, making the celadon product extremely beautiful and hard. It marks the beginning of a new era in Chinese ceramic production.

In the Song and Yuan Dynasties, ancient craftsmen used the technology of wrought iron and pig iron in addition to the technology of steelmaking. The "Tuangang" and "Iron Filling" technologies are actually liquid carburizing and steelmaking methods. Shen Kuo of the Northern Song Dynasty described the preparation method of the Tuangang in "Meng Xi Bi Tan", which is "the use of 'soft iron' to bend it, but the 'born iron' is in the middle, the mud seals the refining, the forging order is in, that' Tuangang." Compared with solid carburizing, liquid carburizing has the advantages of fast permeation speed, uniform thickness of the layer and stable product quality. The ancient Chinese with a solid foundation for smelting pig iron created a liquid carburizing method with molten pig iron as a carburizing agent, which greatly promoted the ancient steel manufacturing industry in China. The beginning of liquid carburizing is still unclear. It is very likely that the "three hundred people drumming charcoal, gold and iron enamel" depicted in "Wu Yue Chun Qiu" is the beginning of liquid carburizing. The technique of using liquid carburizing method to obtain "filling steel" may be very early. Zhang Xie of the Western Jin Dynasty has "the sword of Chu, the slogan of Ouye, which is the refining of the smoldering, the tens of thousands of irrigation." The so-called "irrigation" here may refer to "filling steel". In the Song Dynasty, the steel was popular throughout the country, and it has replaced the steel and the steel. It became the main steelmaking method at that time. This is an original achievement of ancient Chinese heat treatment technology.

During the Ming and Qing Dynasties, ancient Chinese artisans used many heat treatment techniques. There are many related records. For example, Song Yingxing's "Heavenly Creations" in the Ming Dynasty, Fang Yizhi's "Physical Little Knowledge" in the Ming Dynasty, Xu Shouji's "Continuous Guangwu Zhizhi" in the Qing Dynasty, and Chen Keshu's "Engraving" in the Qing Dynasty. During this period, Chinese craftsmen also invented the quenching control heat, such as pre-cooling and quenching. Pre-cooling quenching is beneficial for reducing tool distortion and improving tool toughness. In the "Tiangong Kaiwu" of Song Yingxing in the Ming Dynasty, there was a record of using pre-cooling and quenching technology: "It has been slashed into a longitudinal oblique text, and when it is drawn obliquely, Fang Chengyan. After burning, red, cold, Into the water health." Among them, "returning slightly cold" is the pre-cooling and quenching process.

In terms of chemical heat treatment, great progress has been made in the application of liquid carburizing methods for steel making. At this time, the so-called "cast iron pouring" technology is used, and the steel produced is called "Su Steel". Song Yingxing mentioned in the "hammer forging" article the process of surface treatment of cookware by liquid carburizing method.锄Use “wrought iron forging, melting pig iron to pour, water into the quenching, and become rigid.” It can be seen that the process is to carburize the cookware in the molten pig iron, the purpose is to make the surface into high carbon steel. After quenching, martensite is obtained and strengthened. A ruthenium solid carburizing process is employed on the solid carburizing treatment. In the Ming Dynasty, Song Yingxing’s "Heavenly Creations" recorded a technique of solid carburizing. He wrote: "Where the needle is first, the hammer iron is a thin strip. With a steel ruler, the cone is a line, and the strip is drawn. Iron into a line, cut into needles one by one. First smash the end into a Ying, use a small scorpion to knock the flat, just cones to wear the nose, re-examine the outside. Then into the kettle, slow fire fried simmer. After frying, the end of the pine fire, The soybean meal is covered with three kinds of materials and steamed under the fire." It can be seen that the carburizing at that time was carried out in the kettle. The external heating method was used. The solid carburizing agent was a kind of charcoal in the solid carburizing agent. The same book indicates that the fire is wood. The product obtained by "unclosed hole fire" is the main infiltration agent: soybean meal is also a carbon-containing substance is an auxiliary infiltration agent: the soil is a dispersing agent, which has a certain effect on preventing the mutual bonding of carbonaceous substances and the precipitation of carbon black. . This is exactly the same as today's boxed solid carburizing methods. Solid/liquid carburizing treatment is different from solid or liquid carburizing. It is a carburizing method in which a solid substance is used as a skeleton or a carrier, and a liquid substance is an infiltrant. The most common solid/liquid carburizing process is paste carburizing, which involves mixing carbonaceous materials into a viscous material to form a paste that is applied to the surface of the workpiece. During subsequent heat treatment, carbon penetrates into the surface of the workpiece. In order to obtain a liquid phase in the paste, it is common to add a salt to the paste, and the salt is often in a molten state at 600-900 °C.

"People's Figure" refers to: "Shofar, chaotic hair, ash, fine research, water adjustment, coating knife mouth, burning red, grinding." The main components of the horns and chaos after calcination are calcium oxide, calcium carbonate and Fully burned biokeratin, these substances contain carbon. Among them, calcium oxide and calcium carbonate are mainly used as carriers, and the biokeratin which is not fully burned is a carbon infiltrant. In the Ming dynasty "Physical Mind" "Instrumental Class? Quenching knife method", simply use uncalcined biokeratin as carbon infiltrant: "One with horns, chaotic hair for the end, adjust the knife edge, do not have to lick the crisp and naturally bury "The horns and chaotic hair are the main carbonaceous materials, and the carbon content is higher than that of the ash. The "sweet cake" is the juice under the suede, which is a bio-fat. The oil can not only be used as a binder, but also as a carburizing agent:" The main component of natural ash is sodium carbonate. It seems that the key to the beginning of this process is the use of glutinous rice as an additive, and later developed into a process that uses natural ash as an important additive. Both of these additives are necessary, and the application of natural ash is a significant advance, not only because the natural ash source is relatively broad, but more importantly because sodium carbonate has a significant carbon atom permeation effect. At present, liquid chemical heat treatment commonly uses sodium carbonate as a carburizing accelerator, and it also has a permeation effect in the paste.

At the latest in the Song Dynasty, the traditional Chinese metal foil manufacturing industry is very mature. In the ancient books such as "Heavenly Creations" and "Drawing Things", it is recorded that after the gold pieces are forged, the layers are layered into special Wujin paper, bundled, forged and annealed. The intermediate annealing treatment may be carried out in a charcoal furnace together with burlap paper and heated at a temperature of about 100 ° C to eliminate work hardening. The final annealing treatment is to use the waste heat of forging to slowly cool the gold piece together with the burlap paper to room temperature. Thanks to the unique use of the unique process of Wujin paper spacing, beam forging and annealing, it is possible to produce a thinner and more uniform gold foil than abroad. In addition to gold foil, there are records of silver foil in ancient China. Silver foil is mainly used for the decoration of utensils. In the Yuan Dynasty, Tao Zongyi's "Nancun 辍 录 》 " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " The new cotton is hardened.” Tin foil is a large amount of metal foil, and its biggest use is to make paper money and decoration. The manufacture of tin foil has also been reported in ancient books. The processing is also carried out by layer lamination forging and annealing. The difference is that the ancients may realize that the surface of the tin easily forms a barrier layer (ie, an oxide layer), so that no paper space is used between the metal sheets. Since then, steam annealing heating technology has been developed [19]. By steam heating, the temperature can be controlled to be slightly higher than 100 ° C, which can achieve high ductility and avoid excessive oxidation of the tin foil.

Since modern times, China's traditional iron smelting has been unable to meet the needs of the market, although there are still local production of "Irrigation Steel" or "Su Steel", such as in Wuhu in Anhui, Xiangtan in Hunan, Chongqing in Chongqing, Weiyuan and other places. This traditional technique is used, but nationwide, this traditional liquid carburizing method is no longer the primary means of steelmaking. On the one hand, China's steel relies on imports, and on the other hand, it has begun to build a modern steel plant. Since 1868, the Fuzhou Shipbuilding Bureau Iron Works, Jiangnan Machinery Manufacturing Bureau Steel Plant, Hanyang Iron Works Hanyeping Coal Iron Plant Branch, National Capital and Xingtie Plant, Yangzi Machinery Company Iron Works Benxi Lake Coal and Steel Co., Ltd. have been built. The company's steel production plants, which not only produce iron and wrought iron, but also provide a large amount of steel. At this time, the traditional heat treatment technology formed by accumulating long-term experience still plays an important role in metal processing. Surface treatment techniques for liquid carburizing using molten pig iron as a carburizing agent have also been developed. These methods are commonly referred to as "scratch" or "scratch", and there are many different treatment methods in different regions. In Jiangxi, it is similar to the "cast iron drip" technology described by Song Yingxing. The Hebei, Shanxi, Inner Mongolia and other regions use the "soiling" method, while the northeast region uses the "penetration" method. Fujian and Guangdong are more like "Boiled infiltration" method. It has matured in the process control of quenching and tempering. For example, folks have developed many techniques in the selection of quenching agents and in the control of steel chilling, such as "quenching yellow fire" and "quenching white fire" [20] Wait. In the knife and scissors manufacturing industry, some famous brand names have also been established, including Beijing Wang Mazi and Hangzhou Zhang Xiaoquan. Although they do not know the internal organization of the knife and scissors, they have summarized the craftsmanship in the long-term practice, making it It can achieve the purpose of performance control, so that the cutting tool is tough and durable. The method of solid carburizing has become an important technology for carburizing. It has been used by artisans in Central China and North China in modern times. The “kettle” used by them is iron pot, and the steel prepared is called “焖钢”.

2. Progress in modern heat treatment in China

Heat treatment is a very important basic process in the mechanical industry. It plays an important role in improving the intrinsic quality and service life of mechanical and electrical products and strengthening the competitiveness of products in the domestic and foreign markets. But people realize that it takes a long time and a big price. Since the heat treatment affects the intrinsic quality of the product, it generally does not change the shape of the product, does not make it intuitively felt necessary, and can cause severe distortion and cracking; damage the surface quality and dimensional accuracy of the product, Caused the manufacturing process to be abandoned. Therefore, in the manufacturing industry in China, there has been a phenomenon of “re-cooling (cold processing) light heat (hot processing)”, so that the industry has been in a backward state.

Due to the weakness of the industrial base and the damage suffered during the war, China's heat treatment was only a kind of workshop-style production in the 1940s, and it has not yet formed a substantial industry. There is no specialized discipline in heat treatment in engineering colleges, and thus there is a lack of high-level professional and technical personnel. At that time, the heat treatment operation was mostly a home-based technique, covering a mysterious atmosphere and in a very backward situation.

China's heat treatment industry originated from 156 enterprises aided by the Soviet Union in the early 1950s. The machinery factory has a heat treatment workshop and a section. Purchased a large number of Soviet-made heat treatment equipment, including 30- or 40-year-old resistance heating furnaces such as box type, well type, salt bath, etc., and correspondingly established the first batch of electric furnace plants that produced these types of equipment according to Soviet drawings. After the adjustment of the department, some higher engineering schools created the heat treatment specialty included in the mechanical manufacturing process department. From 1954 to 1956, they trained the first batch of undergraduate and undergraduate heat treatment professional graduates. In the late 1950s and early 1960s, there were also a group of international students studying heat treatment from the Soviet Union. Some scientific research institutions and colleges established in succession can basically carry out research and development of heat treatment foundation and application technology according to the pace of material and application development, and a series of scientific research achievements have emerged. As a result, a relatively complete professional system has been formed from the aspects of talent cultivation, research and development, production technology innovation and equipment manufacturing.

Due to the disconnection between scientific research and production applications, the neglect of innovative production equipment and the short-sightedness caused by long-term closure of the country, the heat treatment production technology of machinery and metallurgical factories in the 1960s and 1970s did not show significant progress. It was not until the 1980s that communication with the international community was realized, advanced technology and equipment were introduced, and the production techniques of some large-scale backbone enterprises have changed significantly.

2.1 Current status of heat treatment industry

According to the investigation of the China Heat Treatment Industry Association in formulating the “Eleventh and Five-Year Plan” of the national heat treatment industry, the heat treatment in China in 2003 summed up the following basic conditions:

2.1.1 Total number of enterprises

There are about 15,000 heat treatment plants, branch factories, workshops, joint-stock companies and private heat treatment enterprises in the national all-round enterprises. Among them, 80% of the enterprises owned by the whole people have 12,000, and 20% are private and joint-stock enterprises, about 3,000. Due to the restructuring of state-owned SMEs in many parts of the Mainland, private enterprises in the cities of East China and South China are still emerging. Many foreign-funded enterprises are preparing to set up heat treatment plants in coastal cities. The total number of private and joint-stock enterprises will continue in the late 10th Five-Year Plan period. rise.

2.1.2 Total number of heat treatment employees

According to the national 15,000 heat treatment plants, each with an average of 25 employees, the total number of employees nationwide is about 370,000. Among them, the proportion of enterprise technicians averaged 8%, about 370,000; the management staff was about 9%, about 33,000.

2.1.3 Total number of heat treatment heating equipment

According to the number of enterprises accounting for 5% of the total number of enterprises in the country, the national heat treatment heating equipment (with a standard of 75kW) is about 150,000 units, and the installed capacity is 11×106kW.

2.1.4 Heat treatment capacity

The average production capacity of each equipment is 100kw/h, the national average is 1.5 shifts, and the annual production capacity of 150,000 heating equipment is nearly 45×106t.

2.1.5 Heat treatment energy consumption

The average utilization rate of heat treatment heating equipment is 30%, the national average is 1.5 shifts, and the actual annual heat treatment capacity of 150,000 sets of equipment is 13.5×106t, and the total power consumption is 9.9×109kW.h.

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