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The aim of this study is to model the distribution patterns of the different mechanical properties of a submerged arc welded pipeline steel API X70 and to investigate the relationship between Vickers hardness and other mechanical properties of API X70. In this study, serial mechanical properties of 70 pipes, formed by spiral submerged arc welding of high strength low alloy steel (HSLA) API X70, were measured in base metal and weldments. Four main statistical distributions: Normal, Log-normal, Weibull and smallest extreme value distributions were chosen to test the goodness of fit to the experimental data. As a result, normal and lognormal distributions can equally model the distribution patterns of the whole experimental data of studied mechanical properties except for the hardness and toughness of the base metal that can be approximated by Weibull and smallest extreme value distributions, respectively. Using the current data, a weak but statistically significant correlation is obtained only between the toughness of the fusion zone and the hardness of both the base metal and the heat affected zone. Consequently, the calculated regression models were unable to estimate impact toughness values based on future measures of Vickers hardness components.

<p>The effects the concentration of cobalt on zinc-cobalt alloys obtained from sulphate baths under continuous current deposition are described. The deposit morphology was analyzed using Scanning Electron Microscopy (SEM) and an X-Ray Diffraction (XRD) was used to determine the preferred crystallographic orientations of the deposits. Protection against corrosion properties studied in a solution of 3 % NaCl in the potentiodynamic polarization measurements (Tafel), electrochemical impedance spectroscopy (EIS) to the potential of corrosion free. The parameters that characterize the corrosion behavior can be determined from the plots and Nyquist plots. It has been observed that the Zn–Co alloy is characterized by enhanced the resistance of corrosion compared to the Zn alloys. and the addition of Co in the Zn-Co increases the micro-hardness, XRD and SEM results an identify any coatings Zn-Co alloy composition reveals that. zinc-rich( η- phase) , cubic Co₅Zn₂₁.</p>

The aim of this work is to study the influence of the E6010 and E8018-G fluxes on the chemical composition, microstructure, formation of inclusions and micro hardness in different passes (P1, P2 and P3) of X42 welded steel. The marketed chemical composition of used fluxes is: E6010 and E8018-G, which have a low carbon electrodes. The fusion zone microstructure consists of acicular ferrite. The fluxes (FA and FC) have the high TiO2 and SiO2 contents respectively. The high content of Ti and Si, was also detected in the melted zones (P1 ,P2 and P3). The MnO2 oxide proportion in the fluxes (E6010, and E8018-G) is constant (0.94-0.99). However, the Mn content increases in the melted zones (P3 and P1). The highest percentages of Si and Mn was detected in the outer and inner passes respectively of melted zone, relatively to the base metal. The variation of the elements mass concentrations (Mn, Cr, Si and Ti) shows a contradictory variation on the three points in the melted zone passes (P1 and P3). White and black non-metallic inclusions are observed regardless the used flux. The micro-hardness in the multi-pass melting zone with the fluxes (E6010 and E8018-G) varies according to the variation of the equivalent carbon in the different filler metals.