THE EFFECT OF NON-METALLIC INCLUSIONS ON THE CRAK PROPAGATION IMPACT ENERGY OF TOUGHENED 35B2+Cr STEEL
DOI:
https://doi.org/10.7494/mafe.2008.34.1.115Keywords:
structural steel, impact energy of crack propagation, non-metallic inclusions, tougheningAbstract
35B2+Cr steel was designed as a material for screws. The investigations were carried out on toughened samples, taken from three ingots of 35B2+Cr steel (delivered from three various steel suppliers), and of different content of non-metallic inclusions. In each case, the fraction of non-metallic inclusions was in agreement with the corresponding standard. This study presents the results of the research focused on the influence of non-metallic inclusions on the impact energy of crack development in 35B2+Cr steel. The role of non-metallic inclusions was considered both in relation to their total fraction and in relation to the fraction of oxides, sulfides, nitrides and exogenous inclusions separately. Assuming linear dependence between notch-root radius and the impact energy of crack nucleation, basing on the impact toughness tests, the impact energy of the crack development was evaluated. It was proved, that in spite of the level of fraction of non-metallic inclusions compatible with the corresponding standards, they directly or indirectly influence the impact energy of 35B2+Cr steel. This influence depends on the character of the inclusions.
Downloads
References
Lis T., RóżańskiP.: Inclusions engineering in liquid steel. Hutnik, Wiadomości Hutnicze 72, 5 (2005) 256-264 (in Polish)
Różański P., Paduch J.: Modification of non-metallic inclusions in steels with enhanced machinability. Archives of Metallurgy 48, 3 (2003) 285-307
Kang Y.-B., Kim H.S., Zhang J., Lee H.-G:. Practical application of thermodynamics to inclusions engineering in steel. J. of Physics and Chemistry of Solids 66, 2-4 (2005) 219-225
Li J.-H., Chen S.-H., Xi T.-H., Chen X:. Effect of microalloyed Ti on inclusions modification. J. of Iron and Steel Research 14, 5, supp. 1 (2007) 320-324
Lis T.: Characterization of typical non-metallic inclusions in clean steels. Hutnik, Wiadomości Hutnicze 75, 3 (2008) 106-109 (in Polish)
Sojka J., Jeróme M., Sozańska M., Vdńovd P., Rytifovd L., Jonsta P. Role of microstructure and testing conditions in sulphide stress cracking of X52 and X60 API steels. Materials Science and Engineering A, 480, 1-2 (2008) 237-243
Elkoca O., Cengizler H.: Cracking during cold forming process of rear brake component. Engineering Failure Analysis 15, 4 (2008) 295-301
Yang Z.G., Li SX., Zhang J.M., Zhang J.F., Li G. Y., Li Z.B., Hui W.J., Weng Y.Q.: The fatigue behaviors of zero-inclusion and commercial 42CrMo steels in the super-long fatigue life regime. Acta Materialia 52, 18 (2004) 5235-5241
Jha Abhay K., Sreekumar K., Mitkal M.C'.: Metallurgical studies on a failedEN 19 steel shearpin. Engineering Failure Analysis 15, 7 (2008) 922-930
Beretta S., Ghidini A., Lombardo F.: Fracture mechanics and scale effects in the fatigue of railway axles. Engineering Fracture Mechanics 72, 2 (2005) 195-208.
Costa e Silva A.: Thermodynamic aspects of inclusion engineering in steel. Rare Metals 25, 5 (2006) 412— 419
Pacyna J.: Physical metallurgy of tools steels cracking. Metallurgy and Foundry Engineering 120 (1988) 134-148 (in Polish)
Niezgodziński T., Kubiak T., Młodkowski A.: Phenomenon of lamellar tearing in numerical calculation. Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika 73 (2001) 233-239 (in Polish).
Gulaev A.P.: (Rozłożenie udarnoj vjazkosti na ee sostavljajuscie po dannym ispytanija abrazcov s raźnym nadrezom - The decomposition of impact energy on the components on the ground of tests of impact strength samples with different notches). Zavodskaja Laboratorija 33 (1967) 473-475 (in Russian).
