Powder injection moulding of premixed ferritic and austenitic stainless steel powders

Sotomayor, M.E.; Levenfeld, B.; Várez, A.

doi:10.1016/j.msea.2011.01.038

Cited by 34 publications

(24 citation statements)

References 35 publications

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“…CPVC was experimentally determined by means of oil absorption ASTM D-281-31 method using Thermo Haake Rheomix mixer (Universiti Kebangsaan Malaysia (UKM), Selangor, Malaysia) where 0.5 mL volume of oleic acid was added to 200 g of SS316L powder for every 5 min [30]. If the addition of oil continues, the torque value decreases abruptly indicating that the critical powder volume concentration is reached [31]. Equation (1) is employed to obtain the CPVC using powder volume (V p ) and acid oleic volume (V o ) at the point where the torque is a maximum.…”

Section: Methodsmentioning

confidence: 99%

“…It can be observed that the viscosity of all the feedstock decreases with increasing shear rate which indicates pseudoplastic behavior [1] and leads to good wettability of the binder and metal powder [35]. The shear rate range of 100 s´1 to 10,000 s´1 was selected because it is similar shear rate values obtained during injection stage [31]. For the feedstock to be successfully injected, viscosity values recommended for MIM process must be less than 100 Pa.s for viscosity and 100 s´1 to 10,000 s´1 in shear rate [31,36].…”

Section: Rheological Behaviormentioning

confidence: 99%

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Influences of Restaurant Waste Fats and Oils (RWFO) from Grease Trap as Binder on Rheological and Solvent Extraction Behavior in SS316L Metal Injection Molding

Ibrahim

Amin

Asmawi

et al. 2016

Metals

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This article deals with rheological and solvent extraction behavior of stainless steel 316L feedstocks using Restaurant Waste Fats and Oils (RWFO) from grease traps as binder components along with Polypropylene (PP) copolymer as a backbone binder. Optimal binder formulation and effect of solvent extraction variables on green compacts are being analyzed. Four binder formulations based on volumetric ratio/weight fraction between PP and RWFO being mixed with 60% volumetric powder loading of SS316L powder each as feedstock. The rheological analysis are based on viscosity, shear rate, temperature, activation energy, flow behavior index, and moldability index. The optimal feedstock formulation will be injected to form green compact to undergo the solvent extraction process. Solvent extraction variables are based on solvent temperature which are 40˝C, 50˝C, and 60˝C with different organic solvents of n-hexane and n-heptane. Analysis of the weight loss percentage and diffusion coefficient is done on the green compact during the solvent extraction process. Differential Scanning Calorimeter (DSC) is used to confirm the extraction of the RWFO in green compacts. It is found that all binder fractions exhibit pseudoplastic behavior or shear thinning where the viscosity decreases with increasing shear rate. After considering the factors that affect the rheological characteristic of the binder formulation, feedstock with binder formulation of 20/20 volumetric ratio between PP and RWFO rise as the optimal binder. It is found that the n-hexane solvent requires less time for extracting the RWFO at the temperature of 60˝C as proved by its diffusion coefficient.

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Section: Methodsmentioning

confidence: 99%

Section: Rheological Behaviormentioning

confidence: 99%

Influences of Restaurant Waste Fats and Oils (RWFO) from Grease Trap as Binder on Rheological and Solvent Extraction Behavior in SS316L Metal Injection Molding

Ibrahim

Amin

Asmawi

et al. 2016

Metals

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“…Raza et al suggested that for successful metal injection molding the shear rate ranges between 102 and 105 s -1 and the maximum suitable viscosity for feedstock is 103 Pa at the molding temperature [30]. Considering the viscosity values recommended for PIM process, less than 1000 Pa s in the shear rate range between 100 and 1000 s −1 [31]. So as to inject the feedstock into injection molding machine, the viscosity and shear rate should be 1000 Pa.s and in the range of 100 to 10000 s -1 respectively [32].…”

Section: Fluiditymentioning

confidence: 99%

An Analysis of Rheological Properties of Inconel 625 Superalloy Feedstocks Formulated with Backbone Binder Polypropylene System for Powder Injection Molding

Gökmen

Türker

2017

Archives of Metallurgy and Materials

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B inder formula is one of the most significant factors which has a considerable influence on powder injection molding (PIM) processes. In the study, rheological behaviors and properties of different binder systems containing PIM feedstocks, Inconel 625 powder commonly used in space industry, were investigated. The feedstocks were prepared 59%-69% (volume) powder loading ratios with three diversified binder systems by use of Polypropylene as backbone binder. The average particle size of the Inconel 625 powder used was 12.86 microns. Components used in the binder were mixed for 30 minutes as dry in three dimensional mixing to prepare binder systems. Rheological features of the feedstock were characterized by using a capillary rheometer. Viscosities of the feedstocks were calculated within the range of 37.996-1900 Pa.s based on the shear rate, shear stress, binder formula and temperature. "n" parameters for PIM feedstocks were determined to be less than 1. Influences of temperature on the viscosities of the feedstocks were also studied and "Ea" under various shear stresses were determined within the range of 24.41-70.89 kJ/mol.

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“…Besides that, the removal rate of PS and NaCl was rapidly increased until achieved plateau stage at certain period. Based on the study done by Sotomayor et al (2011), solvent debinding typically consist of two stages; dissolution and diffusion. Higher rate of extraction during initial stage was because the solvent has direct contact with the solute (PS and NaCl) so the distance is shorter.…”

Section: Debindingmentioning

confidence: 99%

Development of Porous Ti-6Al-4V Mix with Palm Stearin Binder by Metal Injection Molding Technique

Jamaludin¹,

Kasim²,

Nor³

et al. 2015

American Journal of Applied Sciences

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Good potential of biocompatibility and excellent mechanical properties, porous Ti-6Al-4V has become a great interest for biomedical applications. In this study, porous Ti-6Al-4V was fabricated by Metal Injection Molding (MIM) using Palm Stearin (PS) and Polyethylene (PE) binder together with sodium chloride (NaCl) as a space holder. Rheological characterization was performed to evaluate the flowability of the feedstocks for injection molding and the feedstocks exhibited a pseudoplastic behavior which is suitable for injection. The as-sintered parts were fabricated as the mixing, injection molding, debinding and sintering were conducted successfully. The mechanical properties of the as-sintered parts were investigated via tensile test and the results obtained were closed with the established range. Shrinkage, density and X-Ray Diffractometry (XRD) of the as-sintered parts were compared with the theoretical values which were found closed to the acceptable ranges. The microstructure of the surface and cross-section were observed under Scanning Electron Micrograph (SEM) and optical microscope to analyze the specimens before and after sintering. Generally, palm stearin binder system added with space holder to fabricate porous Ti-6Al-4V by MIM is feasible and has shown a good potential for biomedical applications.

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Powder injection moulding of premixed ferritic and austenitic stainless steel powders

Cited by 34 publications

References 35 publications

Influences of Restaurant Waste Fats and Oils (RWFO) from Grease Trap as Binder on Rheological and Solvent Extraction Behavior in SS316L Metal Injection Molding

Influences of Restaurant Waste Fats and Oils (RWFO) from Grease Trap as Binder on Rheological and Solvent Extraction Behavior in SS316L Metal Injection Molding

An Analysis of Rheological Properties of Inconel 625 Superalloy Feedstocks Formulated with Backbone Binder Polypropylene System for Powder Injection Molding

Development of Porous Ti-6Al-4V Mix with Palm Stearin Binder by Metal Injection Molding Technique

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