Generally speaking, the definition of alloying element content less than 50% is heat-resistant steel. Japanese heat-resistant steel standards include JIS G4311, G4312 and various SUH series standards. According to the different matrix structures, heat-resistant steel can be divided into ferritic heat-resistant steel, martensitic heat-resistant steel, austenitic heat-resistant steel and drain type heat-resistant steel. JIS G5122 specifies SUH heat-resistant steel nozzles. However, steel products are not classified by primary structure. Ferritic heat-resistant steel, martensitic heat-resistant steel and austenitic heat-resistant steel are mixed together.
Precision casting is a more traditional casting method. During the machining process, a relatively precise shape and high casting accuracy can be obtained. In the process of processing, it is necessary to make electrodes for the required raw materials, and then form cavities in detail according to the corrosion form of the electrodes, and then perform wax casting by selecting a casting process, so that the original wax pattern can be preserved.