Metal (S136 die steel) heat treatment is a process that heats metal workpieces to a suitable temperature in a certain medium, and then maintains this temperature for a certain period of time, and then cools at different speeds.
Heat treatment of metal (S136 die steel) is one of the important processes in mechanical manufacturing. Compared with other processing techniques, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but by changing the microstructure inside the workpiece, or changing The chemical composition on the surface of the workpiece gives or improves 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 have the required mechanical properties, physical properties and chemical properties, in addition to the reasonable selection of materials and various forming processes, heat treatment processes are often essential. Steel (S136 die steel) is the most widely used material in the machinery 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, etc. and their alloys can also change their mechanical, physical and chemical properties through heat treatment to obtain different performance.
In the process of progressing from the Stone Age to the Bronze Age and Iron Age,
The role of heat treatment is gradually recognized. As early as 770 BC to 222 BC, Chinese people have discovered in production practice that the performance of copper and iron will change due to the influence of temperature and pressure deformation. The softening treatment of white cast iron is an important process for manufacturing agricultural 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 rapidly developed. Both swords and a halberd unearthed in Yanxia, Yi County, Hebei Province, China, have martensite in their microstructure, indicating that they have been quenched.
With the development of quenching technology, people gradually discovered the influence of quenching agent on the quality of quenching. Pu Yuan, a Shuman from the Three Kingdoms, once made 3,000 knives for Zhuge Liang in Xiegu, Shaanxi. It is said that he was sent to Chengdu for water quenching. This shows that China has paid attention to the cooling capacity of different water qualities in ancient times, as well as the cooling capacity of oil and urine. The sword in the tomb of King Jingshan, Zhongshan, unearthed from the Western Han Dynasty (206 BC to 24 AD) in China, has a carbon content of 0.15 to 0.4% in the heart, but a surface carbon content of more than 0.6%, indicating that the carburizing process has been applied. But as a secret of personal "craft" at that time, he refused to circulate it, so it developed very slowly.
In 1863, British metallologists and geologists showed six different metallographic structures of steel (S136 die steel) under the microscope, proving that the structure of the steel will change when heated and cooled. The phase changes to a harder phase during rapid cooling. The iron isomerization theory established by the French Osmond and the iron-carbon phase diagram first formulated by the British Austin laid a theoretical foundation for the modern heat treatment process. At the same time, people have also studied the method of protecting the metal during the heating process of the metal (S136 die steel) heat treatment to avoid oxidation and decarbonization of the metal during the heating process.
From 1850 to 1880, there were a series of patents for the protection and heating of various gases (such as hydrogen, coal gas, carbon monoxide, etc.). From 1889 to 1890, British Lake obtained a patent for bright heat treatment of various metals.
Since the twentieth century, the development of metal physics and the transplantation and application of other new technologies have made the metal (S136 die steel) heat treatment process more developed. A significant progress was from 1901 to 1925. In the industrial production, the rotary furnace was used for gas carburizing; the dew point potentiometer appeared in the 1930s to make the carbon potential of the furnace atmosphere controllable. , Oxygen probes and other methods to further control the carbon potential of the furnace atmosphere; in the 1960s, heat treatment technology used the role of plasma fields to develop ion nitriding and carburizing processes; the application of laser and electron beam technology also made metal (S136 mold Steel) has obtained new surface heat treatment and chemical heat treatment methods.