Variation in particle size fraction to optimize metal injection molding of water atomized 17–4PH stainless steel feedstocks

Metal injection molding (MIM) is a near net shape manufacturing technique for producing small, complex, precision parts in mass production. MIM process is manufacturing method that combines traditional shape-making capability of plastic injection molding and the materials flexibility of powder metallurgy. The process consists of the following four steps: mixing of metal powder and binder, injection molding to shape the component, debinding to remove the binder in the component, sintering to consolidate the debound parts. In this research, the physical and mechanical properties of metal injection molded 17-4 PH stainless steel were investigated with the variation of sintering temperatures (1300 °C - 1360 °C) and atmosphere conditions (argon and vacuum conditions). The relative density, microstructure, distortion, and hardness are measured and analyzed in this study. The results show that highest relative density of 87%, relative homogeneous shrinkage and high hardness are achieved by sintering at 1360 °C for 1.5 hours and argon atmosphere. At the same sintering temperature and time, sintering in vacuum shows lower relative density (81%) than that in argon condition due to pores growth. The pore growths were not observed in the argon atmosphere. It can be concluded that sintering stages more rapidly under vacuum condition. The hardness measurements result also showed that high hardness is obtained by high density parts. The optimum average hardness obtained in this study is 239 HV. However, the hardness properties results are still lower than 280 HV according to MPIF Standard 35 for MIM parts.

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Distribution of total bacteria and staphylococci in PM2.5, PM10 and total dust in the emission of two fattening pig houses/Verteilung von Gesamtbakterien und Staphylokokken in PM2,5, PM10 und Gesamtstaub in der Emission von zwei Mastschweineställen

Gefahrstoffe ◽

10.37544/0949-8036-2020-09-22 ◽

2020 ◽

Vol 80 (09) ◽

pp. 344-348

Author(s):

M. Clauß ◽

S. Linke ◽

A. C. Springorum

Keyword(s):

Particle Size ◽

Size Fraction ◽

Airborne Bacteria ◽

Dispersion Modelling ◽

Particle Size Fraction ◽

Collection System ◽

Total Dust ◽

Dust Distribution ◽

Selective Collection ◽

Total Bacteria

The particle size distribution of airborne bacterial conglomerates is an important factor in calculating possible spread distances of the bacteria over the air. Therefore, a size-selective collection system based on an emission impinger was developed to compare the distribution of total bacteria and staphylococci in particle fractions PM2.5, PM10 and total dust in the emission of two fattening pig stables. Mean emissions of 7.2 × 104 cfu/m³ total bacteria, 6.1 × 104 cfu/m³ staphylococci and 2.8 × 106 cells/m3 measured. About 30% of total bacteria and staphylococci were found in the PM2.5 particle size fraction and about 60% in PM10. The average dust distribution was 80% PM10 and 60% PM2.5. The results show that airborne bacteria from fattening pig units mainly occur on larger particles and do not correlate with dust fractions. The found conditions should be considered in future dispersion modelling.

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The Characterization and Flow Behavior of 316L Stainless Steel Feedstock for Micro Metal Injection Molding (μMIM)

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.44-47.2872 ◽

2010 ◽

Vol 44-47 ◽

pp. 2872-2876

Author(s):

Pei Li Haw ◽

Norhamidi Muhamad ◽

Hadi Murthadha

Keyword(s):

Stainless Steel ◽

Injection Molding ◽

316L Stainless Steel ◽

Flow Behavior ◽

Palm Stearin ◽

Metal Injection Molding ◽

Injection Molding Process ◽

Binder System ◽

Molding Process ◽

Rheological Characterization

The rheological behaviors of the Micro Metal Injection Molding feedstock are important for the stability of the feedstock during micro injection molding process and quality of the final micro-components. Homogeneous feedstocks are preferable for MIM process to ensure the dimensional consistency of molded components and prevent the defects of powder-binder separation or particle segregation. In this work, feedstocks with various formulations of 316L stainless steel and binder system were prepared by using Brabender Plastograph EC Plus mixer. The binder system comprises of palm stearin, polyethelene (PE) and stearic acid. In order to obtain the viscosity, activation energy, flow behavior and mold ability index, the rheological characterization of the feedstocks were investigated in numerous conditions by using Shimadzu 500-D capillary rheometer The study showed that all of the 316L stainless steel feedstocks are homogenous with pseudo-plastic behaviors.

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Metal Injection Molding Method of Ni-Free Austenitic Stainless Steel II - Microstructure and Mechanical Properties

Advanced Materials Research - Advanced Materials and Processing ◽

10.4028/0-87849-463-4.19 ◽

2007 ◽

pp. 19-22

Author(s):

Midori Komada ◽

Yoshikazu Kuroda ◽

Ryo Murakami ◽

Noriyuki Tsuchida ◽

Yasunori Harada ◽

...

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Austenitic Stainless Steel ◽

Injection Molding ◽

Metal Injection Molding ◽

Molding Method ◽

Microstructure And Mechanical Properties

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Laser Diffraction as An Innovative Alternative to Standard Pipette Method for Determination of Soil Texture Classes in Central Europe

Water ◽

10.3390/w12051232 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1232

Author(s):

Dušan Igaz ◽

Elena Aydin ◽

Miroslava Šinkovičová ◽

Vladimír Šimanský ◽

Andrej Tall ◽

...

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Soil Texture ◽

Polynomial Regression ◽

Texture Classification ◽

Size Fraction ◽

Laser Diffraction ◽

Classification Systems ◽

Particle Size Fraction

The paper presents the comparison of soil particle size distribution determined by standard pipette method and laser diffraction. Based on the obtained results (542 soil samples from 271 sites located in the Nitra, Váh and Hron River basins), regression models were calculated to convert the results of the particle size distribution by laser diffraction to pipette method. Considering one of the most common soil texture classification systems used in Slovakia (according to Novák), the emphasis was placed on the determination accuracy of particle size fraction <0.01 mm. Analysette22 MicroTec plus and Mastersizer2000 devices were used for laser diffraction. Polynomial regression model resulted in the best approximation of measurements by laser diffraction to values obtained by pipette method. In the case of particle size fraction <0.01 mm, the differences between the measured values by pipette method and both laser analyzers ranged in average from 3% up to 9% and from 2% up to 11% in the case of Analysette22 and Mastersizer2000, respectively. After correction, the differences decreased to average 3.28% (Analysette22) and 2.24% (Mastersizer2000) in comparison with pipette method. After recalculation of the data, laser diffraction can be used alongside the sedimentation methods.

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