1. Put the austenitized Ductile Iron workpiece into Isothermal Quenching Furnace and hold it at 230-370℃ for 60-90min, to transform the matrix structure of Ductile Iron , obtain acicular ferrite, that is, lower bainite, and retained austenite, so that ADI castings can achieve High Temperature strength, high Hardness , low Plasticity .
2. Place the austenitized Ductile Iron workpiece into a nitrate salt isothermal furnace and hold it at 370-500℃ for 60-90min, so that the matrix structure of Ductile Iron transforms to obtain a mixture of lath-shaped ferrite and precipitated carbides, namely upper bainite, so that the heat-treated ADI casting achieves high Plasticity , Low Temperature ness, and low Hardness .
3. Due to the fact that the austenitized Ductile Iron needs to be rapidly cooled from 865°C High Temperature to 230-500°C within the nitrate salt Isothermal Quenching Furnace , and must be maintained at a constant temperature and isothermal state for a certain period of time, it transforms into bainitic ferrite.
High Temperature Ductile Iron When the workpiece enters Isothermal Quenching the first dozens of Second , High Temperature a large amount of heat from the workpiece needs to be exchanged into the nitrate salt solution, the liquid nitrate salt will heat up extremely quickly, and the nitrate salt solution temperature rises rapidly Liter will produce two major serious destructive effects.
One reason is that it is impossible to instantly cool the workpiece to Isothermal Quenching constant temperature. If this cannot be achieved, the Ductile Iron quality of the Quenching workpiece will be greatly reduced.
Second, it is an important Safe problem. Since the nitrate salt solution is composed of 55% potassium nitrate and 45% sodium nitrite, nitrate salt itself is a raw material for making explosives. When the temperature of nitrate salt reaches above 550°C, combustion and explosion will occur.
Therefore, Ductile Iron the workpiece Isothermal Quenching has extremely high requirements for nitrate salt Isothermal Quenching Furnace . It must be Safe non-explosive, capable of extremely rapid cooling, and also Precision constant temperature isothermal. Local overheating is absolutely not allowed, and over-temperature is even more unacceptable. The heat exchange between the nitrate salt solution and the workpiece during the isothermal transformation process must be uniform, and the temperature uniformity must reach ±3℃.
After many Year studies, Hankou Furnace the company has designed and successfully applied the nitrate salt Isothermal Quenching Furnace that fully meets the above requirements.
It gathers on-site Isothermal Quenching Furnace from all over the country including Hubei, Hunan, Shandong, Shanxi, Henan, Hebei, Guangdong, Guangxi, as well as Equipment cases from all over the world including exported to the United States, Germany, Japan, South Korea, Singapore, Malaysia, Indonesia and other countries.
Hankou Furnace boasts 50 years of manufacturing experience
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