caa a22 4500 465771327 CHVBK 20180323111929.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF00727242 doi (NATIONALLICENCE)springer-10.1007/BF00727242 High-temperature cracking resistance in cast steel in reforming oven tubes [Elektronische Daten] [G. Nikiforchin, O. Student, I. Skripnik, G. Kostenko, S. Ripets'kii] Summary: Results are given from high-temperature tests (770, 870, 920, and 960°C) to estimate the short-time and cyclic cracking resistance for cast NK-40 steel tubes from reforming ovens in the initial state and after use for 75,400 h. The crack growth resistance in static loading has been determined from the crack resistance limit, and in cyclic loading from the kinetic diagrams for the fatigue failure in terms of the crack growth ratev against the scale of the nominal stress intensity coefficient ΔK. Metallography shows that there are differences in structure in the various states, and material that has been used has pores and microcracks, whose numbers are largest in the inner wall layers. Cyclic tests with constant ΔK show substantial increase in the crack growth rate in the defective material. The cracking stability limit falls as the test temperature rises, while the fatigue crack growth rate increases, particularly above 920°C. Increased asymmetry in the loading cycle (R=−1; −0.5; 0; 0.4) is accompanied by deterioration in the cyclic cracking resistance. There are two opposite trends in the effects of loading frequency (f=0.001-10 Hz) on the failure kinetics: in the high-amplitude loading range, reduction inf increases the crack growth rate, while in the low-amplitude range, there is a decrease. The results are explained in terms of creep and fatigue crack opening. Plenum Publishing Corporation, 1990 Nikiforchin G. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut Student O. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut Skripnik I. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut Kostenko G. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut Ripets'kii S. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut Soviet materials science : a transl. of Fiziko-khimicheskaya mekhanika materialov / Academy of Sciences of the Ukrainian SSR Kluwer Academic Publishers-Plenum Publishers 26/2(1990-03-01), 183-188 0038-5565 26:2<183 1990 26 11003 https://doi.org/10.1007/BF00727242 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00727242 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nikiforchin G. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut NATIONALLICENCE 700 1- Student O. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut NATIONALLICENCE 700 1- Skripnik I. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut NATIONALLICENCE 700 1- Kostenko G. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut NATIONALLICENCE 700 1- Ripets'kii S. Karpenko Physicomechanics Institute, Academy of Sciences of the Ukrainian SSR, L'vov aut NATIONALLICENCE 773 0- Soviet materials science : a transl. of Fiziko-khimicheskaya mekhanika materialov / Academy of Sciences of the Ukrainian SSR Kluwer Academic Publishers-Plenum Publishers 26/2(1990-03-01), 183-188 0038-5565 26:2<183 1990 26 11003 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer