Application possibilities of the low-temperature repairs on creep-resistance turbine components from material GX23CrMoV12-1

Abstract

Papers deals with the problems of repairs at new and also already loaded components of steam and gas turbines. Generally, it is about welding repairs at valve and turbine chambers, transmitters, vane carriers, tripping valve body and so on. There are both technological defects caused by casting (e.g. shrinkage cavities, misruns, porosity and cracks) and defects caused by operation (thermal-stress fatigue, incorrect method of operation, etc.). Many of the mentioned defects take effect not until the final technological method - mostly at machining. However, in this production phase it is not possible to get form the supplier new production elements due to economical and also delivery time reasons. All of that results in delay of production and penalty. As the major aim of this paper, there was to find such repairs techniques which can ensure serviceability of mentioned devices under the standard regime. In these cases is needed to use much lower tempering temperature than under the standard production, mainly because of necessity to eliminate deformation caused by heating of part that is not possible to be subsequently removed by machining.

Archives of Foundry Engineering

“…Erosive wear occurs in a variety of different industries, in machinery, and can cause significant financial losses. For these reasons, it is justified to protect surfaces that are exposed to erosion to decrease damage and financial loss caused by replacement or repair of machines components [1][2][3][4].…”

Archives of Metallurgy and Materials

“…Among these materials which have a potential for further improvement of processing parameters are the martensitic 9-12% Cr steels. These steels offer a very good combination of strength properties, resistance against high-temperature oxidation and creep, low price and good processability [4][5][6][7][8][9][10]. However, it is also important to take into account the problems encountered in welding these materials.…”

“…However, it is also important to take into account the problems encountered in welding these materials. Steels used in nuclear energy have a problems related with tendency to cold cracking, hydrogen embrittlement and very often require complicated preheating and post weld heat treatment operations [5][6][7][8][9][10].…”

“…Due to the specificity of technology and the degree of advancement of materials and technologies to combine them, it is also important to conduct research on their properties change during the manufacturing processes. One of such processes that significantly change the properties of the material is the welding process [8][9][10][11][12][13][14]. The degree of complexity of the ma-chine elements and construction produced by this technology causes that more and more often we must use the possibilities offered by today's modern software for numerical analyses of welding and heat treatment processes.…”

“…This type of software allows for a significant extension the possibilities of designing modern power installations by providing engineers with a lot of important information about both the process itself and its effects. Significant reduction of the number of tests necessary to run on real samples as well as often inability to perform them due to the dimensions and weight of the structure gives unprecedented possibilities to design modern power installations, at the same time with very significantly reduced financial outlays [4,8,[14][15][16][17][18][19].…”