1. Microstructural investigation of the heat-affected zone of simulated welded joint of P91 steelTomaž Vuherer, Marko Dunđer, Ljubica Milović, Milorad Zrilić, Ivan Samardžić, 2013, izvirni znanstveni članek Opis: In the process of testing real components exposed to elevated temperature, it is not possible to neglect cracks. The most significant cracks can be induced by welding, which is applied for joining of structural components. Pressure equipment in service is also exposed to high pressure and high stresses. Materials for their manufacturing are designed to resist high stressat elevated temperature, and to meet requirements regarding creep resistance. The objective of this study is to investigate microstructure of different regions of the heat affected zone in T/P91 steels by using thermal simulation instead of welding.
Ključne besede: welded joints, microstructures, P91 steel, heat-affected zone, heat treatment
Objavljeno v DKUM: 10.07.2015; Ogledov: 1022; Prenosov: 159
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3. Vloga in nastanek mikrostrukturnih sestavin M-A v zvarnih spojih maloogljičnih visokotrdnostnih konstrukcijskih jekelZdravko Praunseis, Masao Toyoda, Alojz Križman, Mitsuru Ohata, 2001, pregledni znanstveni članek Opis: The existence of martensite-austenite constituents in the weld metal and heat-affected zone seriously reduces the fracture toughness of the welded joint. Therefore, we have investigated the formation of the martensite-austenite constituents when high-strength low-alloy steel is welded with a high heat input or using multi-pass welding. This paper deals with the effects of martensite-austenite constituents on the fracture toughness, the metallurgical features of the martensite-austenite constituents, and the prevention and elimination of the martensite-austenite constituents in the welded joints.
Ključne besede: arc welding, high-strength low-alloy steels, microstructure, martensite-austenite constituents, weld metal, heat-affected zone, cooling rate
Objavljeno v DKUM: 01.06.2012; Ogledov: 1840; Prenosov: 118
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4. Some factors affecting fatigue resistance of weldsVladimir Gliha, Zijah Burzić, Tomaž Vuherer, 2010, objavljeni znanstveni prispevek na konferenci Opis: The fatigue strength of polycrystalline metals is hardness and defect size dependent. The fatigue strength of welds depends on the size of grains and actual local mean stress, too. Local mean stress is influenced by the global R-ratio and static preloading. The welds in the as-welded condition are pre-stressed due to the existence of welding residual stresses. The sign and magnitude of residual stresses depend on the welding conditions. Changes of residual stresses, hardness and defect size are experimentally determined in the present work. Samples of studied metals are prepared by using either thermal cycle simulator or laboratory furnace and water quenching. The methods of microstructure preparation and type of load result in actual local R-ratio at the used weld toe models. Specimens are cyclic loaded in the similar way as steel at the weld toe. The bottom of the notch is either defect-free or defected by Vickers indentation. Final results show that coarser grain and higher local R-ratios lower the fatigue strength of welds.
Ključne besede: CrNiMo steels, weld, fatigue resistance, heat-affected zone, small weld defects
Objavljeno v DKUM: 31.05.2012; Ogledov: 1484; Prenosov: 26
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