Adam Zieliński

By Grzegorz Golański, Adam Zieliński and Hanna Purzyńska

Creep-resisting austenitic steels constitute a group of construction materials which can work in the conditions of creep for the temperature range from 550 to 700°C. The service of austenitic steels leads to the progressive degradation of their microstructure, which results in the changes of functional properties. The main mechanisms of degradation of the austenitic steel microstructure include the processes of matrix softening, the processes of precipitation and matrix depletion of the interstitial and substitution elements. Precipitation processes in austenitic steels are a very important indicator, which allows the advancement of microstructure degradation processes in these steels to be determined. Hence, the knowledge of the impact of individual secondary phases on the microstructure and properties of austenitic steels plays a very important role in diagnosing the components and equipment of the power boiler system and makes it possible to forecast the time of safe operation of systems made from these steels. Based on own studies and data from literature, this paper will present the characteristics of secondary phase precipitates occurring in creep-resistant austenitic steels during their operation at an elevated/high temperature. The effect of secondary precipitates on mechanical properties of these steels will be discussed too.

Part of the book: Austenitic Stainless Steels

By Tomasz Tański, Marek Sroka and Adam Zieliński

Part of the book: Creep

By Adam Zieliński, Marek Sroka, Tomasz Tański and Grzegorz Golański

Part of the book: Creep Characteristics of Engineering Materials

By Janusz Dobrzański and Adam Zieliński

The assessment of suitability for further service of the basic material and circumferential welded joints of primary steam pipelines made of 14MoV6-3 steel was made based on the determined characteristics of their mechanical properties and structure. The tests were carried out on materials after service significantly exceeding the design time and 200,000 h. The mechanical properties with respect to the determined class of structure for the basic and welded joint material were compared to the determined class of damage in accordance with the Institute for Ferrous Metallurgy’s own classification of the condition of materials after service under creep conditions. The residual life and disposable residual life were determined based on short-term creep tests and referred to the class of existing structure and the class of damage. The assessment of the suitability of the basic and circumferential welded joint material for further service was made.

Part of the book: Creep Characteristics of Engineering Materials