On 2018-08-08 14:48:54
Heat treatment of metal S136 die steel
Heat treatment of metal (S136 die steel) is a process in which the metal workpiece is heated to an appropriate temperature in a certain medium and kept at this temperature for a certain period of time before being cooled at different speeds.
Metal (S136 die steel) heat treatment is one of the important processes in mechanical manufacturing, compared with other processing processes, heat treatment generally does not change the shape of the workpiece and the overall chemical composition, but by changing the microstructure of the workpiece, or change the chemical composition of the workpiece surface, give or improve the performance of the workpiece. Its characteristic is to improve the inherent quality of the workpiece, which is generally not visible to the naked eye.
In order to make the metal workpiece with the required mechanical properties, physical properties and chemical properties, in addition to the rational selection of materials and various forming processes, heat treatment process is often essential. Iron and steel (S136 die steel) is the most widely used material in the mechanical industry, the microstructure of iron and steel is complex, 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 be changed by heat treatment mechanical, physical and chemical properties, in order to obtain different performance.
In the progress from the Stone Age to the bronze and iron ages,
The role of heat treatment is gradually recognized. As early as 770 ~ 222 BC, the Chinese had discovered in their production practices that the properties of copper and iron could change with the influence of temperature and pressure deformation. The softening treatment of white cast iron is an important technology for making farm tools.
In the sixth century BC, steel weapons were gradually adopted. In order to improve the hardness of steel (S136 die steel), the quenching process was developed rapidly. Two swords and a halberd unearthed in yanxiadu, yixian county, hebei province, China, have martensite in their microstructure, indicating that they have been quenched.
With the development of quenching technology, the influence of quenchants on quenching quality is gradually discovered. Pu yuan, a native of shu in The Three Kingdoms, made 3000 swords for zhuge liang in the present-day xiegu, shaanxi province. This suggests that the Chinese noticed the cooling power of different water quality in ancient times, as well as the cooling power of oil and urine. The sword in the tomb of king jing of zhongshan in the western han dynasty (206 bc-ad 24) unearthed in China has a carbon content of 0.15-0.4% in the core and more than 0.6% on the surface, indicating that the carburizing process has been applied. But as a personal "craft" of the secret, not to be spread, so the development of slow.
In 1863, British metallographers and geologists demonstrated six different metallographic structures of steel (S136 die steel) under a microscope, demonstrating that the internal structure of steel changes as it is heated and cooled, and that the hot phase changes to a harder phase when it is cooled sharply. The theory of iron isomerism established by the French osmond and the first diagram of iron carbon prepared by the British Austin laid the theoretical foundation for the modern heat treatment process. At the same time, people also studied the protection of metal during the heat treatment of metal (S136 die steel) in order to avoid the oxidation and decarburization of metal during the heating process.
From 1850 to 1880, there were a number of patents for the application of various gases (hydrogen, gas, carbon monoxide, etc.) for protective heating. 1889 ~ 1890 British person lake obtained a variety of metal bright heat treatment patent.
Since the 20th century, the development of metal physics and the transplantation of other new technologies have led to a greater development of the metal (S136 die steel) heat treatment process. One notable development was the application of rotary burners for gas carburizing in industrial production from 1901 to 1925. In the 1930s, a dew-point potentiometer appeared to control the carbon potential of the atmosphere in the furnace. Later, a method was developed to further control the carbon potential of the atmosphere in the furnace with carbon dioxide infrared instrument and oxygen probe. In the 1960s, the heat treatment technology used the role of plasma field, the development of ion nitriding, carburizing process; With the application of laser and electron beam technology, new surface heat treatment and chemical heat treatment methods have been obtained for metal (S136 die steel).