Search for dissertations about: "m23c6"

Showing result 1 - 5 of 15 swedish dissertations containing the word m23c6.

  2. 1. Aspects of microstructural evolution in chromium steels in high temperature applications

    Author : Åsa Gustafson; KTH; []
    Keywords : Cr-steels; nucleation; coarsening; model; DICTRA; precipitates; carbides; carbo-nitrides; MX; VN; M23C6; TiC; TEM; EFTEM; Curie-temperature;

    Abstract : In this thesis 9-12 % Cr steels, used for high-temperaturecomponents in fossil-fired power plants are considered. Thecreep strength of thees steels depend on their microstructurethat consists of a matrix of tempered lath martensite withdensely distributed precipitates. READ MORE

  4. 2. Precipitation Reactions at High Temperatures in 9-12% Chromium Steels

    Author : Mats Hättestrand; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; thermo-dynamical simulations; creep resistant; 9-12% chromium steel; energy filtered TEM; precipitates; atom probe field ion microscopy; quantitative metallography;

    Abstract : This thesis reports on quantitative investigations of microstructural changes, mainly precipitation reactions, occurring during heat treatment, ageing and creep of 9-12% chromium steels. Several alloys with varying composition have been investigated. READ MORE

  5. 3. Precipitate stability in creep resistant 9-12% chromium steels

    Author : Ardeshir Golpayegani; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; growth; precipitates; coarsening; atom probe field ion microscopy APFIM ; energy filtered TEM EFTEM ; 9-12% chromium steel;

    Abstract : 9-12% chromium steels are used extensively in modern steam power plants at service temperatures up to 600°C. These materials are subjected to creep deformation during exposure which is the limiting factor in increasing the steam temperature and thus the thermal efficiency of the plants. READ MORE

  6. 4. Microstructure and Mechanical Properties of High Chromium Steel Weld Metals

    Author : Guang-Jun Cai; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : The microstructure of three types of Cr steel weld metals, containing 5%, 9% and 12% chromium, was studied in different heat treated conditions using optical microscopy, analytical transmission electron microscopy and atom probe field-ion microscopy. The mechanical properties of the weld metals were investigated. READ MORE

  7. 5. Evolution of Microstructure in Two Austenitic Alloys at High Temperatures

    Author : Jenny M Erneman; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; N ; Thermo-Calc; Nb C; gamma prime; DICTRA; APFIM; quantitative metallography; AISI 347; Alloy 800; energy filtered TEM; sigma phase;

    Abstract : A niobium stabilised AISI 347 austenitic stainless steel was investigated after static ageing and creep deformation at temperatures between 500°C and 800°C for times up to 88 000 h. Coarse and fine NbX precipitates and also s-phase precipitates were formed in the temperature range 500-700°C. READ MORE