scholarly journals Dilatometric Analysis of Anisotropic Dimensional Changes in a 16 Pct Cr Stainless Steel with a Planar Banded Structure

2010 ◽  
Vol 41 (6) ◽  
pp. 1429-1440 ◽  
Author(s):  
Javad Mola ◽  
Dongchul Chae ◽  
Bruno C. De Cooman
Keyword(s):  
Stainless Steel ◽  
Banded Structure ◽  
Dilatometric Analysis ◽  
Dimensional Changes

Densification and Properties of 420 Stainless Steel Produced by Three-Dimensional Printing With Addition of Si3N4 Powder

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Li Sun ◽  
Yong-Ha Kim ◽  
Dave (Dae-Wook) Kim ◽  
Patrick Kwon
Keyword(s):  
Stainless Steel ◽  
Three Dimensional ◽  
Shape Distortion ◽  
Three Dimensional Printing ◽  
Dimensional Changes ◽  
Si3n4 Powder ◽  
Sample Shape ◽  
Knoop Microhardness ◽  
Dimensional Printing ◽  
Kinetics Of

This study is aimed to investigate the effect of adding Si3N4 on the three-dimensional printing (3DP) processed 420 stainless steel (SS). The final density, dimensional changes, and mechanical properties have been studied for the samples prepared under a series of sintering conditions. The contents of Si3N4 powder ranging between 0 wt % and 15 wt % and the sintering temperature were varied in the experiments in order to understand the dependence of densification kinetics and changes in properties on these process parameters. The experiments provide the evidence that the addition of Si3N4 can improve the densification kinetics of 420 SS significantly. The 420 SS samples produced by 3DP with 12.5 wt %Si3N4 sintered at 1225°C for 6 h yielded 95% relative density, 190 GPa Young’s modulus, and 500 Knoop microhardness without any major sample shape distortion. The results are promising in that the 3DP process can be used to yield the prototype almost equivalent to a real part with a full mechanical capacity.

Studies on Martensite Transformation in a Metastable Austenitic Cr-Mn Stainless Steel

2013 ◽  
Vol 762 ◽  
pp. 424-430 ◽  
Author(s):  
Anna P. Kisko ◽  
Ludovica Rovatti ◽  
R.D.K. Misra ◽  
Puspendu Sahu ◽  
Juho Talonen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Heating Rate ◽  
Magnetic Measurements ◽  
Isothermal Holding ◽  
Ferromagnetic Phase ◽  
Annealing Duration ◽  
Heating Rates ◽  
Dimensional Changes ◽  
Transmission Electron ◽  
Cold Rolled

The influences of the heating rate and annealing duration on martensite formation and its reversion to austenite have been investigated in a 60% cold-rolled metastable high-manganese austenitic Type 204Cu stainless steel. A Gleeble 3800 thermomechanical simulator was used for dilatometric measurements. Cold-rolled steel pieces were either heated up to 1000 °C at various heating rates between 5 °C/s and 150 °C/s followed by quenching to room temperature, or heated and held at temperatures in the range of 450 620 °C for different durations between 0.1 600 s. In heating experiments, dilatation curves revealed an expansion of a specimen starting around 550 °C followed by contraction, both processes depending on the heating rate. These dimensional changes could be correlated to the formation and reversion of a ferromagnetic phase, α-martensite. Some martensite was also formed during isothermal holding in connection with tempering of the pre-existing α-martensite before the following reversion, as established by magnetic measurements. Tempering of martensite was revealed by microhardness behaviour, X-ray diffraction analysis and transmission electron microscopy.

scholarly journals Dimensional accuracy of different impression techniques of partially edentulous mandibular arch

2017 ◽  
Vol 65 (1) ◽  
pp. 25-29
Author(s):  
Rafael Pino VITTI ◽  
Victor Pinheiro FEITOSA ◽  
Ataís BACCHI ◽  
William Cunha BRANDT ◽  
Milton Edson MIRANDA ◽  
...  
Keyword(s):  
Stainless Steel ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Acrylic Resin ◽  
Reference Points ◽  
Vitro Study ◽  
Dimensional Changes ◽  
Mandibular Arch ◽  
Body Techniques

ABSTRACT Objective: The purpose of this in vitro study was to assess and compare the dimensional accuracy of three impression techniques: 1-step putty/light-body, 2-step putty/light-body, and the monophase technique. Methods: A partially edentulous standard stainless steel mandibular arch cast with reference points on the teeth was used to make the impressions. The anteroposterior and transverse distances were measured. All impressions were made with a polyvinyl siloxane using stock metallic (1- and 2-step putty/light-body techniques) or acrylic resin (monophase technique) trays. The monophase impressions were made using a light-body material and the 1- and 2-step putty/light-body impressions with putty and light-body materials. After impression procedures, the accuracy of each technique was assessed measuring the stone casts (n = 5) poured from the impressions using a microscope at 30x magnification and at 0.5 µm accuracy. The data were analyzed statistically using 2-way ANOVA and Tukey's test (p<0.05). Results: Stone casts made by all techniques had significantly negative linear changes (shrinkage). The anteroposterior distances showed more dimensional changes than the transverse distances. The edentulous side showed more shrinkage than the anteroposterior side. Conclusion: No differences between the impression techniques were found, but significant dimensional changes were observed.

NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al

1983 ◽  
Vol 41 ◽  
pp. 202-203
Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Alloy Composition ◽  
Chromium Content ◽  
Scale Up ◽  
Optical Metallography ◽  
Property Evaluation ◽  
310 Stainless Steel ◽  
Microstructural Studies

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.

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