The alloy wear-resistant castings in cocrw generally lack the strengthening phase of * * * lattice. Although their strength at middle temperature is low (only 50-75% of that of nickel-based alloys), they have high strength, good thermal fatigue resistance, thermal corrosion resistance and wear resistance, and good weldability above 980℃. It is suitable for manufacturing guide vanes and nozzle guide vanes of aviation jet engines, nozzles of industrial gas turbines, marine gas turbines and diesel engines. The main carbides in the carbide strengthening phase cocrw are MC, M23C6 and M6C. M23C6 precipitates between grain boundaries and dendrites during slow cooling in casting cocrw. In some alloys, fine M23C6 can form * * * crystals with matrix γ. MC carbide particles are too large to have a significant effect on dislocation directly, so the strengthening effect on the alloy is not obvious, while fine dispersed carbides have a good strengthening effect.

Only by standardizing the design of squeeze casting die can wear-resistant castings develop faster and better. After the casting is taken out of the pouring cooling mold, there are gates, risers, metal burrs, burrs and seams, and sand is still attached to the casting cast by sand mold, which must be cleaned up. The equipment for this kind of work includes polishing machine, shot blasting machine, pouring and riser cutting machine, etc. Sand removal and cleaning of sand castings is a process with harsh working conditions, so when choosing the molding method, we should try our best to create convenient conditions for sand removal and cleaning. Due to special requirements, some castings need post-treatment, such as heat treatment, shaping, rust prevention, rough machining and so on. The casting process can be divided into three basic parts, namely, casting metal preparation, mold preparation and casting treatment. Casting metal refers to the metal material used to pour castings in casting production. It is an alloy with a metallic element as the main component and other metallic or nonmetallic elements. Traditionally called cast alloy, it mainly includes cast iron, cast steel and cast nonferrous alloy.

Quality of raw materials for wear-resistant castings. The quality of metal charge, refractory, fuel, flux, modifier, foundry sand, sand binder, paint and other materials is not up to standard, which will cause defects such as porosity, pinhole, slag inclusion and sand sticking. This will affect the appearance quality and internal quality of cast iron, and even make cast iron scrap in serious cases. Design manufacturability of iron castings. When designing, we should not only determine the geometric shape and size of iron castings according to working conditions and metal material properties, but also consider the rationality of the design from the perspective of casting alloy and casting process characteristics, that is, obvious size effect, solidification, shrinkage and stress, so as to avoid or reduce the occurrence of defects such as segregation, deformation and cracking of iron castings. Generally speaking, for the appearance quality of professional iron castings, the surface roughness of castings can be judged by comparing samples; Micro-cracks on the surface can be checked by coloring method and magnetic particle method. High chromium cast iron with chromium content of 12 ~ 30% and carbon content of 2.4 ~ 3.6% can obtain martensite or austenite or their mixed matrix and special carbide of chromium through high alloying and heat treatment.