TY - JOUR N2 - In the paper the reasons for steam pipeline’s elbow material rupture, made of steel 13CrMo4-5 (15HM) that is being used in the energetics. Based on the mechanical properties in the ambient temperature (Rm, Rp0,2 and elongation A5) and in the increased temperature (Rp0,2t ) it was found, that the pipeline elbow’s material sampled from the ruptured area has lower Rp0,2 i Rp0,2t by around 2% than it is a requirement for 13CrMo4-5 steel in it’s base state. The damage appeared as a result of complex stress state, that substantially exceeded the admissible tensions, what was the consequence of considerable structure degradation level. As a result of the microstructure tests on HITACHI S4200 microscope, the considerable development of the creeping process associates were found. Also the advances progress of the microstructure degradation was observed, which is substantial decomposition of bainite and multiple, with varied secretion size, and in most cases forming the micro cracks chains. With the use of lateral micro sections the creeping voids were observed, that creates at some places the shrinkage porosities clusters and micro pores. L1 - http://www.journals.pan.pl/Content/101896/PDF/afe-2016-0052.pdf L2 - http://www.journals.pan.pl/Content/101896 PY - 2016 IS - No 3 DO - 10.1515/afe-2016-0052 KW - mechanical properties KW - Materials used in the power industry KW - The degradation of microstructure KW - Steel 13CrMo4-5 A1 - Mesjasz, A. A1 - Piątkowski, J. PB - The Katowice Branch of the Polish Academy of Sciences DA - 2016 T1 - The Reasons of Steam Pipeline Elbow Rupture UR - http://www.journals.pan.pl/dlibra/publication/edition/101896 T2 - Archives of Foundry Engineering ER -