Investigate the Behavior of Carbon Percentage and Sintering Temperature on Microstructure and Densification Parameter of Iron-based Powder Preform (original) (raw)
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2013
In this present work effect of temperature and graphite contents on the microstructural and mechanical properties of iron based powder metallurgy freeform was studied. The different graphite contents (0%, 2%, 5% and 10%) were mixed in iron powder and compact them in 100 KN. These specimens were sintered at 7000 C, 8500 C and 10000 C in muffle furnaces. Microstructural properties were evaluated using scanning electron microscopy. Experimental results were compared to determine to best combination of graphite and iron powder preform. Maximum density was found between the range 2% to 5% graphite contents and temperature at 8500C. At graphite contents increases from 0% to 2%, the microstructure of the iron-based powder sintered specimen changes gradually from ferrite and a small amount of pearlite to pearlite, after 2% of graphite contents the microstructure was found pearlite and ferrite. As graphite increase up to 5% gray cast iron structure and at 10000 C temperature range white cast...
Global Journal of Research In Engineering, 2014
The present paper investigates the effect of sintering temperature and graphite content on the microstructure and effect on wear and frictional properties of Fe+C powder metallurgy preforms. For the present work the specimens were prepared with graphite content 0.5%, 1%, 1.5% and 2% by weight and were sintered at three sintering temperature 800°C, 900°C and 1050°C. Microstructural properties were evaluated using scanning electron microscopy. The wear and friction property of the powder preforms were tested on Pin-On-Disc apparatus. The powder specimen was used as pins and the disc was of AISI 51200 steel. The experiments was carried out under load of 40 N, speed 1000 rpm, time 1500 seconds and relative humidity 60% 65%. The result was 2% graphite content specimen with sintering temperature 1050°C showed good wear resistance. The wear rate decreased with the increase in sintering temperature and increase in graphite content of the specimen.
Direct laser sintering of iron–graphite powder mixture
Materials Science and Engineering: A, 2004
In the present work, the role of graphite addition on the laser sintering of iron powder was studied. Powder mixtures containing iron and 0.4, 0.8, 1.2, and 1.6 wt.% graphite were prepared by blending elemental powders. These powders were sintered layer-by-layer under nitrogen atmosphere using a continuous wave CO 2 laser beam. A laser power of 70-225 W, scan rate of 50-600 mm s −1 , scan line spacing of 0.1-0.3 mm, and layer thickness of 0.1 mm was used. It was found that the processing parameters play a key role on the densification of the iron-graphite powder mixtures. The addition of graphite enhances the densification of the iron powder and improves the surface quality of the laser sintered parts when optimized manufacturing conditions are applied. The graphite content has a significant influence on the internal pore structure of the sintered parts. They are gradually changed from interconnected networks to closed and spherical shaped pores with increasing graphite content. The metal matrix structure consists of different phases such as ferrite, austenite, and tempered martensite, which highlights the heterogeneous distribution of dissolved carbon in the iron matrix. This article presents the experimental details of the microstructural evolution in laser sintered iron-graphite powder mixtures. The role and key importance of graphite addition to iron powder in the laser sintering process is addressed.
Archives of Metallurgy and Materials, 2019
The paper presents the effect of manganese on the crystallization process, microstructure and selected properties: cast iron hardness as well as ferrite and pearlite microhardness. The compacted graphite was obtained by Inmold technology. The lack of significant effect on the temperature of the eutectic transformation was demonstrated. On the other hand, a significant reduction in the eutectoid transformation temperature with increasing manganese concentration has been shown. The effect of manganese on microstructure of cast iron with compacted graphite considering casting wall thickness was investigated and described. The nomograms describing the microstructure of compacted graphite iron versus manganese concentration were developed. The effect of manganese on the hardness of cast iron and microhardness of ferrite and pearlite were given.
Materials Science Forum, 2007
Among steel-making techniques Powder Metallurgy (PM) concept utilizes unique production cycle, consisting of powder compaction and sintering steps that give high productivity with low energy consumption and high material utilization. Due to the presence of residual porosity, mechanical properties of PM components are inferior in comparison with structural components produced by other technologies. Improvement of mechanical properties at the same level of porosity can be achieved primarily by adding variety of alloying elements. Therefore modern PM technology for production of high-performance PM parts for highly stressed steel components for automotive industry, for example, rely on techniques of utilization of different alloying elements additionally to adjustment of technological process depending on alloying system used. When talking about high-strength low-alloyed structural steels, the most common alloying elements, additionally to carbon, added in order to increase mechanical performance, are chromium, manganese, silicon and some other strong carbide and carbonitride-forming elements (V, Nb, Ti etc.). In comparison with classical steelmaking practice, alloying of PM steels is much more complicated as additionally to influence of alloying elements type and content on microstructure, mechanical properties, hardenability etc., number of additional aspects influencing powder production and further component processing has to be considered. Traditionally, PM high-strength steels are alloyed with Cu, Ni, and Mo. This results in a considerable difference in price of material between conventional and PM steels, used for the same high-load application, as the price of currently employed PM alloying elements like Mo and Ni is dozens of times higher in comparison with that of Cr or Mn. This situation creates a strong economical stimulation to introduce cheaper and more efficient alloying elements to improve the competitiveness of PM structural parts. So, why the potential of most common for conventional metallurgy alloying elements as Cr, Mn and Si is not utilized in PM? First and basic question that arise is how to introduce these The Sintering Behaviour of Fe-Mn-C Powder System, Correlation between Thermodynamics and Sintering Process, Manganese Distribution and Microstructure Composition, Effect of Alloying Mode 575
2011
Among steel-making techniques Powder Metallurgy (PM) concept utilizes unique production cycle, consisting of powder compaction and sintering steps that give high productivity with low energy consumption and high material utilization. Due to the presence of residual porosity, mechanical properties of PM components are inferior in comparison with structural components produced by other technologies. Improvement of mechanical properties at the same level of porosity can be achieved primarily by adding variety of alloying elements. Therefore modern PM technology for production of high-performance PM parts for highly stressed steel components for automotive industry, for example, rely on techniques of utilization of different alloying elements additionally to adjustment of technological process depending on alloying system used. When talking about high-strength low-alloyed structural steels, the most common alloying elements, additionally to carbon, added in order to increase mechanical performance, are chromium, manganese, silicon and some other strong carbide and carbonitride-forming elements (V, Nb, Ti etc.). In comparison with classical steelmaking practice, alloying of PM steels is much more complicated as additionally to influence of alloying elements type and content on microstructure, mechanical properties, hardenability etc., number of additional aspects influencing powder production and further component processing has to be considered. Traditionally, PM high-strength steels are alloyed with Cu, Ni, and Mo. This results in a considerable difference in price of material between conventional and PM steels, used for the same high-load application, as the price of currently employed PM alloying elements like Mo and Ni is dozens of times higher in comparison with that of Cr or Mn. This situation creates a strong economical stimulation to introduce cheaper and more efficient alloying elements to improve the competitiveness of PM structural parts. So, why the potential of most common for conventional metallurgy alloying elements as Cr, Mn and Si is not utilized in PM? First and basic question that arise is how to introduce these The Sintering Behaviour of Fe-Mn-C Powder System, Correlation between Thermodynamics and Sintering Process, Manganese Distribution and Microstructure Composition, Effect of Alloying Mode 575
METAL 2020 Conference Proeedings, 2020
The subject of this article is the failed bushing used in the car suspension. The claim of the broken bushing came from the car producer. The main aim of this paper was to know if the failure was a green crack as evidenced by steam treatment oxide on the crack interfaces. To check, these items a Scanning Electron Microscope (SEM), hardness testers, and optical microscope were used. The density of the upper edge where the crack occurred was checked. Based on this investigation it was found that the crack was not caused by the rollover application.
Improvement of Mechanical and Physical Properties in Powder Metallurgy
Comprehensive Materials Processing, 2014
h i g h l i g h t s Isostatic graphite (IG) waste powder from the milling of molds for EDM, can be use as filler in advanced cement composites. Mechanical properties and thermal conductivity are increased with IG in cementitious composites. Carbonation of cementitious composites is increased with IG. IG-Cement Composite showed a sealed microstructure and close interphase by SEM analysis. IG used as addition can be new source for low-cost multifunctional cement-based materials.
The ever-increasing development of applying the iron pieces made by powder metallurgy in car industries and other usages depends on making pieces with high density and consequently acceptable physical and mechanical properties. Regarding the effect of decrease in the powder bits' size on improvement of the mechanical characteristics and on decrease in the temperature of sinter, the experiments on the pure iron powder with the bits' size of 5, 45, 63 micron in which 20% of iron nanopowder was added to the powder with the bits' size of 45 micron, have been studied. Mere iron nanopowder also was applied for experiments. Pieces are compacted under 300-850 MPa and lubricants by0.4 and 0.6 percent of the total weight was mixed with the powders. Various amounts of sintering time and sintering temperature were considered for the sintering of the samples. The survey suggested that applying micro powders resulted in an increase in the linear density and the strength at the relatively high temperatures and high keeping times. Sintering temperature and shrinkage has declined considerably with the decrease in the powder size and as a result the strength increases. High strength for products made by smaller powders under high pressures and low sintering temperatures using lubricated frame wall are obtained. SEM pictures from the fracture junctions of the samples show the decrease in porosity due to the close impact of the smaller powder size.