Page 22 - PR 2014 2016 10 Materials and Nanotechnology

298 Materials and Nanotechnology | Progress Report

study aimed to evaluate the accuracy, the
juxtaposition of these parts in the conical
connection and the force required to remove
the abutment in order to check whether they
were greater than the force of chewing.

Figure 27: (a) Scanning electron microscopy image with back-scat-
tered electrons showing the implant / abutment adjustment
without maladjustment, see detail indicated by red arrows. (b) Gap
of 0.5 µm in the part of the neck of the implant.
Grade 91 welded joints

Grade 91 steels have been widely used in
components to work at high temperatures in
power generation plants, petrochemicals and
oil refineries due to their excellent creep and Figure 28: (a) Welded joint between tube and curve - Dimensions
corrosion resistance. Despite these remarkable in millimeters (b) Influence of the tempering time in the various
welding regions (c) Surface of the fracture region, the top sample
properties, some difficulties in welding Grade without lateral expansion of the weld metal (WM-CS) and the
91steels have been encountered, as they may bottom samples with lateral expansion of the weld metal (WM-8h)
(d) Energy absorbed in the impact test x welded joint regions and (e)
exhibit hardness values outside the specified Lateral expansion in WM in the top and in the root.

Instituto de Pesquisas Energéticas e Nucleares