FSTG Special Steel Technology Group, a leading special alloy manufacturer in China, revealed that the company successfully completed the smelting of turbine wheels for heavy-duty gas turbines and GH4706 superalloys with a diameter of 100mm. The composition control and surface quality of alloy ingots have reached the technology Claim.
The project is a national-level scientific research project, which was jointly established by FSTG and ZG Heavy Gas Equipment Technology Group, BJGY High Temperature Alloy Technology Research Institute, China No. 2 Heavy Shipping Equipment Group and other units. Its diameter and weight grades of high-temperature alloy production represent the world today At the highest level, this project requires high standards, and it is necessary to break through the three "world-class" manufacturing problems of large-size superalloy smelting, forging, blanking, and die forging.
The successful smelting of large-size GH4706 forged alloy ingots indicates that the national heavy-duty gas turbine turbine wheel research project has made significant progress in research, and it also marks that FSTG has reached the world advanced level in the smelting technology of super-large-size superalloys. .
It is worth mentioning that special smelting involves vacuum induction smelting (master alloy), electroslag remelting (removal of phosphorus, sulfur, etc.), vacuum self-consumption (removal of nitrogen, hydrogen, oxygen, carbon, etc.), a considerable part of which is related to vacuum related. It can be said that vacuum technology has played a vital role in it.
In the metallurgical industry, the application of vacuum is not only this, but numerous. Such as vacuum distillation, vacuum separation of ore and its semi-products, vacuum reduction of metal compounds, vacuum degassing and refining outside the molten steel furnace, metal vacuum casting, vacuum sintering, vacuum heat treatment, vacuum brazing and vacuum solid-state joining, etc. . Since the development of the vacuum metallurgy industry in the 1950s, the reason why it has been extremely widely used is because the vacuum environment has a series of characteristics in the metallurgical process:
First, the chemical interaction between the substances and the residual gas molecules in the vacuum environment is very weak, so it is very suitable for smelting and refining of ferrous metals, rare metals, ultra-pure metals and their alloys, and semiconductor materials.
Secondly, in vacuum environment, the purpose of degassing and refining of molten steel and vacuum carbon deoxidization can be achieved by reducing the partial pressure of single gas molecules.
Another feature of the vacuum environment is that it has the ability to perform certain reactions at lower temperatures. For example, at the same temperature, some reaction processes are difficult to perform in the atmosphere, but it is very easy at low temperatures. This is the basic principle of vacuum compound decomposition and non-ferrous metal smelting.