The heat treatment of metal (S136 die steel) is a kind of process that put the metal workpiece in a certain medium and heat it to a suitable temperature, and keep it in this temperature for a certain time, and then cool it at different speeds.
Heat treatment of metal (S136 die steel) is one of the important processes in mechanical manufacturing. Compared with other processing technologies, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but endows or improves the service performance of the workpiece by changing the microstructure inside the workpiece or the chemical composition of the workpiece surface. Its feature is to improve the internal quality of the workpiece, which is generally not visible to the naked eye.
In order to make the metal parts have the required mechanical, physical and chemical properties, in addition to the reasonable selection of materials and various forming processes, heat treatment process is often essential. Steel (S136 die steel) is the most widely used material in the mechanical industry. The microstructure of steel is complex and can be controlled by heat treatment, so the heat treatment of steel is the main content of metal heat treatment. In addition, aluminum, copper, magnesium, titanium and their alloys can also change their mechanical, physical and chemical properties through heat treatment to obtain different service properties.
The role of heat treatment is gradually recognized by people. As early as 770-222 B.C., Chinese people have found that the properties of copper and iron will change due to the influence of temperature and compression deformation. The softening treatment of white cast iron is an important technology in the manufacture of agricultural tools.
In the sixth century BC, iron and steel weapons were gradually adopted. In order to improve the hardness of steel (S136 die steel), the quenching process developed rapidly. Two swords and a halberd unearthed in yanxiadu, Yixian County, Hebei Province, China, have martensite in their microstructure, indicating that they are quenched.
With the development of quenching technology, it is gradually found that the effect of quenching agent on quenching quality. Pu Yuan, a native of Shu in the Three Kingdoms, once made 3000 knives for Zhugeliang in xiegu, Shaanxi Province. It is said that he sent people to Chengdu to get water for quenching. This shows that China has noticed the cooling capacity of different water quality in ancient times, and also the cooling capacity of oil and urine. The sword unearthed in the tomb of King Jing of Zhongshan in the Western Han Dynasty (206-24 A.D.) in China has a carbon content of 0.15-0.4% in the center and more than 0.6% in the surface, indicating that the carburizing process has been applied. But at that time, as the secret of personal "Craftsmanship", it refused to be spread, so it developed slowly.
In 1863, British metallographists and geologists showed six different metallographic structures of steel (S136 die steel) under the microscope, which proved that the structure of steel would change when it was heated and cooled, and the phase of steel at high temperature would change into a harder phase when it was quenched. The theory of iron isomerism established by the French Osmond and the iron carbon phase diagram first established by the British Austin laid a theoretical foundation for the modern heat treatment process. At the same time, people also studied the protection method of metal in the heating process of heat treatment of metal (S136 die steel), in order to avoid the oxidation and decarburization of metal in the heating process.
From 1850 to 1880, there were a series of patents for the application of various gases (such as hydrogen, gas, carbon monoxide, etc.) for protective heating. From 1889 to 1890, lake, an Englishman, obtained a patent for bright heat treatment of various metals.
Since the 20th century, with the development of metal physics and the application of other new technologies, the heat treatment process of metal (S136 die steel) has been greatly developed. A remarkable development is that from 1901 to 1925, the rotary hearth furnace was used in industrial production for gas carburizing, and in the 1930s, the dew point potentiometer appeared, The carbon potential of the atmosphere in the furnace can be controlled. After that, the method of further controlling the carbon potential of the atmosphere in the furnace with carbon dioxide infrared instrument and oxygen probe has been developed. In the 1960s, the heat treatment technology used the role of plasma field and developed the process of ion nitriding and carburizing. The application of laser and electron beam technology also made metal A new method of surface heat treatment and chemical heat treatment was obtained.
On 2018-08-08 11:45:46
