Janusz Dobrzanski

By Janusz Dobrzański

This article describes the method for determination of residual life and disposable residual life based on long- and short-term creep tests for different temperature levels above the operating one and stress level equal to the operating one. The method for determination of the share of disposable life in total life and the time of safe service beyond the design service time was proposed. These characteristics of the steel are used for the evaluation of the structural changes and mechanical properties of the material after long-term operation. The result of this study is the database of material characteristics representing the mechanical properties related to the structure analysis, and it can be used for diagnosis of the components of pressure part of power boilers.

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