The subject of research is car exhaust system piping made of chromium–nickel steel of grade AISI304L with a unique, complex shape that was obtained by hydroforming technology. The purpose of the research was to determine the relation between the microstructure features, surface condition, hardness and the stresses on the external surface as determined by the sin²ψ X-ray method. We found that the stresses were tensile and correlated with the steel hardness, i.e. they were greater where the hardness was higher. Moreover, longitudinal stresses showed a relationship with pipe wall thickness, while circumferential stresses did so only partially. According to our data, the greatest value of stress determined in the pipe amounted to 290 MPa, and was close to the yield point of the strain hardened 304L steel. As depicted via XRD and SEM examination, the pipe stress level and hardness were influenced by the transition γ→α’. Furthermore, in the region of higher stress and hardness, the amount of martensite was 10 vol.%. We also noted that the pipe’s outer surface when subjected to friction against the die shows lesser roughness compared to its inner surface upon exposure to water under pressure.

The effective design of energy-saving electric motors with efficiency class IE4 and higher requires the use of material characteristics that take into account the core shaping process. Therefore, it becomes necessary to use analytical or numerical models that take into account the change of local properties of Fe-Si material. The aim of the work is to indicate a useful analytical model for estimating the local magnetic permeability of the material, as well as to understand the reasons for these changes. For this purpose, low-loss ferromagnetic materials cut with a guillotine and a laser were tested. Rectangular samples, cut at an angle of 0 degrees in relation to the rolling direction, were subjected to macroscopic and microscopic examinations. Finally, the main reasons for changes in material characteristics for both cutting technologies were indicated. Therefore, the proposed model takes into account not only the cutting technology used, but also the current width of the tested strip, for which the material characteristics are to be determined. The parameters of the analytical model are determined on the basis of a limited number of measurements carried out on samples of a simple geometric shape.

Details var a2a_config = a2a_config || {}; a2a_config.onclick = 1; a2a_config.locale = "pl"; a2a_config.color_main = "D7E5ED"; a2a_config.color_border = "9D9D9D"; a2a_config.color_link_text = "ffffff"; a2a_config.color_link_text_hover = "ffffff"; a2a_config.color_bg = "d9d9d9"; a2a_config.icon_color = "#4e4e4e"; a2a_config.exclude_services = ["dihitt", "delicious", "whatsapp", "dzone", "sms", "stumpedia", "viber", "yahoo_messenger", "google_plus"]; Details PDF BIBTEX RIS Title Part III. Kinetics of the (Zn) - Coating Deposition During Stable and Meta-Stable Solidifications Journal title Archives of Metallurgy and Materials Yearbook 2015 Issue No 1 March Authors Sypień, A. ; Kucharska, B. ; Wołczyński, W. ; Garzeł, G. ; Pogoda, Z. ; Okane, T. Divisions of PAS Nauki Techniczne Publisher Institute of Metallurgy and Materials Science of Polish Academy of Sciences ; Committee of Materials Engineering and Metallurgy of Polish Academy of Sciences Date 2015[2015.01.01 AD - 2015.12.31 AD] Identifier DOI: 10.1515/amm-2015-0032 ; ISSN 1733-3490 Source Archives of Metallurgy and Materials; 2015; No 1 March References Wołczyński (2005), A model for solidification of intermetallic phases from Ni - Al system and its application to diffusion soldering of Metallurgy and Materials, Archives, 50, 1055. ; Danielewski (2004), Diffusion in multicomponent systems of Metallurgy and Materials, Archives, 49, 189. ; Jordan (1994), Morphology development in hot - dip galvanneal coatings Metallurgical and Materials, Transactions, 25, 937. ; Wołczyński (2011), Thermodynamic justification for the Ni Ni joint formation by a diffusion brazing of Thermodynamics, International Journal, 14, 97. ; Poku (1988), A study of transient phase bonding process applied to a Ag Ag sandwich joint, Metallurgical Transactions, 19, 675, doi.org/10.1007/BF02649282 ; Wołczyński (2014), Part II Model for the Protective Coating For - mation during Hot Dip Galvanizing of Metallurgy and Materials, Archives, 1393. ; Wołczyński (2014), Part I Thermodynamic and Kinetic Aspects of the Hot Dip ( Zn ) - Coating Formation of Metallurgy and Materials, Archives, 1223. ; Jordan (1997), Zn phases formation in interstitial - free steels hot - dip galvanized at of Materials, Journal Science, 32, 5593. ; Xavier (1996), Further experimental evi - dence to support a simple model for iron enrichment in hot - dip galvanneal coatings on IF steel sheets, ISIJ International, 36, 1316, doi.org/10.2355/isijinternational.36.1316 ; Wołczyński (2011), Meta - stable conditions for diffusion brazing of Metallurgy and Materials, Archives, 311. ; Umeda (1996), Phase selection during solid - ification of peritectic alloys, Acta Materialia, 44, 4209, doi.org/10.1016/S1359-6454(96)00038-9 ; Inagaki (1995), Alloying reactions in hot dip galvanizing and galvannealing processes, ISIJ International, 35, 1388, doi.org/10.2355/isijinternational.35.1388 ; Ghoniem (1972), Uber die feuerverzinkung ents - tenden θ p und θ k schichten in, Metall, 26, 1026. ; Chuang (1975), Kinetics of dif - fusion controlled peritectic reaction during solidification of iron - carbon alloys, Metallurgical Transactions, 6, 235, doi.org/10.1007/BF02673703

Experimental measurements do not allow for a unique determination of the concentration profiles, e.g., in case of multi-layer systems. The measured concentration of the elements at the alloy/scale interface is an average concentration in an alloy and in a scale near the spot of the beam [1]. The knowledge of the concentration of the elements at the boundary is necessary for the understanding corrosion of alloys. This essential obstacle of experimental techniques can be overcome by computer modelling. Namely, by combining the different methods (non-unique measurement with unique modelling). The Danielewski-Holly model of interdiffusion has a unique solution. This model enables to predict the evolution of component distributions in the reacting alloy. The model is valid for time dependent boundary conditions and consequently can be used for modelling the more complex reactions, eg., the formation of complex oxides. To avoid the nonphysical values of fluxes in reacting alloy the kinetic constraint on all fluxes was introduced, i.e., the flux limitation method. The results of the selective oxidation of the P91 steel (0,1 wt.% C, 8,6 wt.% Cr, 0,25 wt.% Ni) are presented. Calculated concentration profiles are compared with the experimental data. We show the evolution of chromium distribution in oxidizing steel up to 3 000 hours. The computations demonstrate that chromium depletion is the key factor determining the scale composition.