Improved fracture toughness of high strength steel aerospace purposes by controlling the morphology of the inclusions.
Summarizes the results of recent research to improve the fracture toughness (K1s) for plane strain typical nizkolegir. 4340 and srednelegir. NU180 and AF1410 vysokoprchnyh St., is now widely used in aerospace engineering. Proper regulation of the morphology of the inclusions affects the effective improvement of these K1s Art. Studies have shown a strong dependence on the volume fraction K1s inclusions and the average distance between them. Cm 4340 K1s determined by the appearance and growth of voids around inclusions MnS. Hence reduction of S is very effective for improving K1s, but in practice this is not always confirmed. The reasons for this deviation. Cm 4240 Obrabrtka calcium improves K1s abruptly. This is due to replacement of MnS on CAS. The results of investigation of the effect of Ca on the mechanical properties of Art. The combination of hot-rolled low-compression improves with heat treatment provides a good balance of strength and toughness at high Cm 4340 mechanical isotropy. of properties. K1s srednelegir. Art improves La and Ti. Given the explanation of the mechanism of this improvement. New conditions for the application of these Art require them not only high strength and toughness, but also high resistance to stress corrosion cracking.