Russians figured out the metallurgy behind those super alloys since the N1 moon rocket era. Blue Origin is running its BE-4 engines on oxidizer-rich preburners and SpaceX’s full-flow Raptor engines are using them too. I want to ask what kind of super alloys they are using? Are those alloys available on the market? Are they too difficult to make?
Googled and found that the alloys mentioned below are available for purchase in Russia.... For example "Steel 12Х18НЮТ" - 195 000 rubles ($3036) per ton
The main recommendations for the selection of structural materials in the production of chamber-liquid jet engines are presented below:
Steel 12Х18НЮТ is used for the inner shells of the cylindrical and tapering part of the chambers at a gas temperature of less than 3000 K, as well as for the inner shell of the expanding parts of the nozzles.
Steel 12Х18Н9Т is currently not recommended for the inner shells of chambers due to the tendency to intergranular corrosion.
It is advisable to use 1X21Н5Т steel to perform power ring chambers, as it does not require heat treatment after welding.
In addition, 1X21Н5Т steel is well welded with bronze, and therefore can be used as an intermediate ring for welding inner shells of 1Х21Н5Т steel and bronze of the БрХ-08 type. Steel 1X21H5T is also recommended for the manufacture of the outer shells of the expanding parts of the nozzles. This steel at the soldering temperature has high ductility, which ensures good contact with the bonds and high quality soldering of complex shapes.
Х16Н4БА steel is used for the manufacture of the outer shell of the cylindrical and tapering parts of the engine chamber, because at temperatures above 500 K, it has high mechanical characteristics.
Titanium alloys are used for the manufacture of the outer and inner shells of the expanding part of the nozzles operating in a reducing environment. For an oxidizing medium, titanium alloys are not recommended, because they can ignite due to cracking of the oxide film.
Copper alloys are used for the manufacture of the inner bottom and inner shells of the cylindrical part of the chamber and the tapering part of the nozzle in engines with high pressure in the chamber (more than 10 MPa).
The choice of material for the combustion chamber of a liquid-propellant rocket engine. Выбор материала для камеры ЖРД