Search Results

You are looking at 1 - 6 of 6 items for

  • Author: M. Blicharski x
Clear All Modify Search
Open access

M. Rozmus-Górnikowska, J. Kusiński and M. Blicharski

The Influence of the Laser Treatment on Microstructure of the Surface Layer of an X5CrNi18-10 Austenitic Stainless Steel

The influence of laser shock processing (LSP) on microstructure of the surface layer of an X5CrNi18-10 austenitic stainless steel was studied. The laser treatment was performed using a Q switched Nd:YAG ReNOVAL laser.

It was found that the laser shock processing performed under the conditions of 230 MW/cm2 laser power density and pulse duration of 18 ns produced an ablation and melting of the thin surface layer of the treated material, what indicated that the process of LSP was not purely mechanical but rather thermo-mechanical one. However SEM images of the sample cross sections showed that clusters of slip bands were formed during the treatment in the near surface region. Transmission electron microscopy of the laser-shock treated steel have also revealed a very high density of dislocations and stacking faults. The changes in microstructure came down to 70 μm.

It has been found that the laser shock processing induced plastic deformation of the surface layer of the investigated material.

Open access

M. Rozmus-Górnikowska and M. Blicharski

Abstract

The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT) method. Investigations were primarily carried out through transmission electron microscopy (TEM) on thin foils prepared by FIB (Focus Ion Beam).

The chemical analysis demonstrated that the amount of certain elements (Fe, Ni, Cr, Mo, Nb) in the transition zone between the base material and the weld overlay changes quickly, from the composition of the steel to the composition of the composite zone. STEM and TEM investigations revealed that two areas are clearly visible in the transition zone. In the narrow band close to the fusion boundary where plates are clearly visible and the M s temperature is higher than room temperature, electron diffraction analyses show reflections of martensite and austenite. Moreover, the crystallographic relations between martensite and austenite can be described by the Kurdjumov-Sachs (K-S) relationship {110}α{111}γ<11¯1>α<11¯0>γ ). The microstructure of the part of the transition zone with an M s temperature lower than room temperature as well as that of the composite zone is austenite. The investigations proved that the width of the martensitic area can be significantly limited by using the CMT technique for weld overlaying.

Open access

M. Rozmus-Górnikowska, Ł. Cieniek, M. Blicharski and J. Kusiński

Abstract

The aim of this work was to investigate the development of microstructure and variations in chemical composition in commercial Inconel 625 coatings on a ferritic-pearlitic steel overlaid by the CMT method.

The investigation showed that microsegregation occurring during the weld overlay solidification makes the dendrite cores to be richer in Ni, Fe and Cr and in the between dendrite arms in Mo and Nb. Niobium shows the strongest tendency to segregation during solidification; molybdenum tends to segregate less and chromium has the lowest tendency to segregation. Although Inconel 625 is a solid solution strengthened alloy, Nb and Mo-rich phases are formed in the between dendrite arms of weld overlays.

Open access

M. Rozmus-Górnikowska and M. Blicharski

The aim of this work was to investigate the microsegregation and precipitates formed due to segregation in Inconel 625 arc weld overlay coatings on boiler pipes. Examination of microsegregation and precipitates were carried out by means of a scanning electron microscope (SEM) equipped with an EDS detector as well as a transmission electron microscope (TEM) equipped with a HAADF (STEM) and an EDS detectors. The presence of precipitations in the weld overlay was also confirmed with X-ray diffraction analysis (XRD) of residue in the form of powder that remained after the electrolytic dissolution of weld overlay matrix.

The investigations showed that the interdendritic regions were considerably enriched during microsegregation with Nb, and less so with Mo. The distribution of Cr and Fe in the weld overlay is relatively uniform. The value of the partition coefficient k for Mo and Nb is lower than 1. Therefore, these elements segregate during solidification into the liquid and, once solidification is finished, the interdendritic regions are considerably enriched with these elements. The value of k for Cr, Ni and Fe are only slightly higher than 1. Though the Inconel 625 is a solid-solution strengthened alloy, precipitation of secondary phases occurs in weld overlays. Precipitations were identified as a Laves phase and carbonitrides (Nb, Ti)(C, N).

Open access

Magdalena Sobczyńska, Tadeusz Blicharski and Mirosław Tyra

Abstract

Relationships between performance test traits (growth rate, backfat thickness, loin depth, lean meat percentage, exterior, phenotypic selection index) and longevity traits (length of productive life, number of litters, total number of weaned pigs, number of weaned piglets per year, number of litters per year) in Landrace sows were evaluated using canonical correlation analysis. The data set consisted of 23,012 purebred sows that farrowed from 1994 to 2011 in 161 herds. The first three canonical correlations (0.37, 0.25, 0.07) were highly significant (P<0.0001). Correlations of the first canonical variate with the original measured variables indicated that sows with high values for this variate had lower growth rate (r=-0.31) and loin depth (r=-0.43), greater backfat thickness (r=0.23), as well as being older at birth of their last litter (r=0.98). These sows also had a greater number of litters (r=0.94) and better lifetime efficiency (r=0.61 and r=0.70 for number of weaned piglets per year and number of litters per year, respectively). Canonical loadings for the second canonical function indicate that sows with high values for the second set of variates had high growth rate (r=0.79) and phenotypic selection index (r=0.83), excellent conformation (r=0.62), as well as better efficiency in pig production (r=0.67). The squared multiple correlations show that the first canonical variate of the performance traits is a poor predictor of longevity (0.13) and nearly useless for predicting efficiency traits (0.07). Performance test traits explain 11% of the variance in the variables of longevity and lifetime productivity, whereas dependent variables explain only 3% of the variance in performance test traits. The relationships between performance test data and subsequent lifetime productivity or longevity were significant and unfavourable but low for Polish Landrace population

Open access

M. Rozmus-Górnikowska, M. Blicharski, J. Kusińsk, L. Kuslnski and M. Marszyck

Abstract

The aim of this work was to investigate different weld overlay coating technologies applied to steel boiler pipes and their influence on microstructure and properties of the produced overlays. The investigations were carried out on the boiler pipes weld overlaid by an Inconel 625 and cladded at various conditions (CMT, GMAW and GTAW). The investigations showed that microstructure and mechanical properties of overlaid pipes depend on cladding technology and the chemical composition of the base material.