Hydro-Québec

About: Hydro-Québec is a government organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Electric power system & Dielectric. The organization has 2596 authors who have published 4433 publications receiving 100878 citations.

Residual stress characterization in low transformation temperature 13%Cr-4%Ni stainless steel weld by neutron diffraction and the contour method

Abstract: This study presents the results of residual stress characterization by neutron diffraction and the contour method on 13%Cr–4%Ni welds made using 410NiMo weld filler metal. The transverse, longitudinal and normal components of stress were determined by neutron diffraction. The longitudinal stress distribution was also measured by the contour method. The last bead of the weld was found to be in a state of triaxial compression while a part of the heat-affected zone as well as a region beneath the weld were in a state of longitudinal tension. These results are explained with reference to the low martensitic transformation start temperature (Ms) of the alloy. The same measurements were made on an identical weld that had undergone a standardized post-weld heat treatment. The maximum tensile stress was reduced from 534 to 136 MPa, and the maximum compressive stress was reduced from 371 to 152 MPa.

XPS investigation of surface oxidation and reduction in nanocrystalline CexLa1 − xO2 − y

Abstract: Inert gas condensation was used to generate nanocrystalline La-doped CeO 2-x . Non-stoichiometric CeO 2-x -based materials were found to he excellent catalysts in recent studies for the selective reduction of SO 2 . To understand better the stoichiometry-related catalytic properties, the surface chemistry of nanocrystalline La-doped CeO 2-x , was investigated through in situ oxidation-reduction thermal treatments. Oxidation in CO 2 and reduction in H 2 atmospheres were performed between 30 o C and 600 o C in a reaction chamber connected to an x-ray photoelectron spectrometer analytical chamber. Curve fitting and target factor analysis were used to obtain a semiquantitative measurement of the transformation between +3 and +4 oxidation states during these reactions. Target factor analysis was found to he a very useful tool for analyzing the contributions corresponding to Ce +3 and Ce +4

Microstructure and wear behavior of Fe-based amorphous HVOF coatings produced from commercial precursors

Abstract: Wear resistant highly amorphous Fe 60 Cr 8 Nb 8 B 24 (at.%) coatings of about 280 μm thickness were prepared through high velocity oxygen fuel (HVOF) thermal spray process onto API 5L X80 steel substrate. Feedstock powders were produced by gas atomization with low purity precursors by modifying AISI 430 stainless steel with additions of niobium (Fe-Nb) and boron (Fe-B). It was found that the coatings were mostly amorphous with some embedded FeNbB and Fe 2 B borides. The formation of a large fraction of amorphous phase was attributed to the high cooling rates of molten droplets combined with a proper powder composition. The average Vickers hardness of the coating (HV 0.3 = 838 ± 23) was about four times higher than that of the API 5L X80 substrate (HV 0.3 = 222 ± 5). The excellent wear resistance of the amorphous coating in the pin-on-disc measurements was attributed to its large fraction of amorphous phase (~ 66%) with reinforcing hard Fe 2 B and FeNbB borides, high Vickers hardness, low oxygen content ( − 5 and 8.5 × 10 − 4 mm 3 ·N − 1 ·m − 1 , respectively). API 5L X80 steel exhibited dominant adhesive wear at low sliding speed and oxidative wear at high sliding speed. HVOF coatings presented oxidative wear regardless of the sliding speed.