STUDY ON COMPLEX SHAPE POWDER METALLURGY IRON-BASED PARTS PREPARED BY WARM FLOW COMPACTION

2008 ◽  
Vol 07 (02) ◽  
pp. 261-265
Author(s):  
ZHIYU XIAO ◽  
LIANG FANG ◽  
SHUHUA LUO ◽  
HONGYUN GAO
Keyword(s):  
Powder Metallurgy ◽  
Apparent Density ◽  
Fine Powder ◽  
Metal Injection Molding ◽  
Form Complex ◽  
Flow Capacity ◽  
Transverse Pressure ◽  
Iron Based ◽  
Metallurgy Iron ◽  
Complex Powder

Warm flow compaction based on warm compaction and metal injection molding is a new net-shape manufacturing technology which can produce complex powder metallurgy (PM) parts by conventional axial-pressing. Warm flow compaction makes use of improved flowability of powder binder mixture in an appropriate temperature to form complex PM-parts, like cross-shaped parts. The effect of the combination of coarse and fine powders on apparent density and flowability as well as the effect of different pressing speed and temperature on lateral flow capacity of iron-based powders were investigated. Results showed that apparent density increases as fine powder fractions increase, and transverse pressure becomes larger when pressing speeds are raised. The transverse pressure increases when the temperature of powder binder mixture approaches the melting point of the binder and the lubricant. The transverse pressure decreases as lateral-distance increases.

Sulfide Transformation from Self-Lubricating to Free-Cutting in Powder Metallurgy Iron-Based Alloys

2020 ◽  
Vol 29 (2) ◽  
pp. 1034-1042
Author(s):  
Fang Yang ◽  
Qian Qin ◽  
Haixia Sun ◽  
Peng Liu ◽  
Zhimeng Guo
Keyword(s):  
Powder Metallurgy ◽  
Iron Based ◽  
Metallurgy Iron

scholarly journals Are Large Particles of Iron Detrimental to Properties of Powder Metallurgy Steels?

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 431
Author(s):  
Ahmed Abdallah ◽  
Mahdi Habibnejad-Korayem ◽  
Dmitri V. Malakhov
Keyword(s):  
Powder Metallurgy ◽  
Apparent Density ◽  
Heavy Tail ◽  
Number Density ◽  
Iron Powders ◽  
Distribution Histogram ◽  
Compositional Uniformity ◽  
Large Particles ◽  
Size Distribution Histogram ◽  
Sintered Materials

It is experimentally shown that a removal of particles exceeding 100 microns in size from iron powders typically used in the fabrication of medium density powder metallurgy steels has a weak effect on apparent density, flowability and compressibility of blends as well as on density and strength of green bodies. An elimination of such particles, i.e., cutting off a heavy tail of a size distribution histogram at the 100 μm threshold, improves a compositional uniformity of sintered materials, but has no noticeable beneficial effect upon the strength of a final product, which is likely be determined by a fraction of pores and their shapes. A presence of soft pearlitic inclusions hardly matters unless their number density becomes so large that a 3D continuity (integrity) of a hard martensitic matrix is lost. This finding suggests that such an expensive preparatory step as sieving away large particles from as-received mixtures would bear no technological advantages. It was experimentally found that an attempt to lower the threshold below 100 μm noticeably worsened apparent density, flowability and compressibility.

Comparison Study in Consolidation of Yttria Reinforced Iron-Chromium Composites Using Conventional and Microwave Sintering Technique

2013 ◽  
Vol 594-595 ◽  
pp. 832-836
Author(s):  
M. Marina ◽  
M.Z.M. Zamzuri ◽  
Mohd Nazree Derman ◽  
Mohd Asri Selamat ◽  
Z. Nooraizedfiza
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Microwave Sintering ◽  
Slow Heating ◽  
Comparison Study ◽  
Sintering Time ◽  
Microwave Furnace ◽  
Crucible Furnace ◽  
Iron Based ◽  
Iron Chromium

This research is focused on studying the density and mechanical properties of iron-chromium composites consolidated by innovative rapid microwave sintering technology against conventionally sintered counterparts using slow heating crucible furnace. Another aim of this study is to assess the viability of yttria (Y2O3) ceramic particulates as reinforcement to the iron-chromium composites. Fabrication of iron-chromium-yttria composites consolidated in microwave furnace and conventional crucible furnace was successfully accomplished. Improvement of density is evident in microwave sintered composites. The Y2O3 addition significantly increases the hardness of the composite (118 Hv for microwave specimens as opposed to 110Hv for conventional specimens). The study also successfully established the viability of microwave sintering technique for consolidating iron based powder metallurgy composites by up to 80% reduction of sintering time.

Tribological properties of double-glow plasma Tungsten-Molybdenum alloyed layer on iron-based powder metallurgy gear materials

2019 ◽  
Vol 6 (8) ◽  
pp. 0865a9
Author(s):  
Zili Liu ◽  
Zhendong Fang ◽  
Dongbo Wei ◽  
Xiqin Liu ◽  
Haohao Li ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Tribological Properties ◽  
Alloyed Layer ◽  
Iron Based ◽  
Glow Plasma

scholarly journals Forming Complex Graded and Homogeneous Components by Joining Simple Presintered Parts of TRIP-Matrix Composite through Powder Forging

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 543 ◽  
Author(s):  
Markus Kirschner ◽  
Stefan Martin ◽  
Sergey Guk ◽  
Ulrich Prahl ◽  
Rudolf Kawalla
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Steel Matrix ◽  
Forming Process ◽  
Form Complex ◽  
Transformation Induced Plasticity ◽  
Graded Structure ◽  
Material Systems ◽  
Significant Step ◽  
Graded Structures

The ability to fabricate complex graded structures would be a significant step towards the manufacturing of material systems with properties tailored to individual applications. While powder metallurgy has had some success in this regard, it requires that the semi-finished products be exactly similar to the final component. However, it is significantly cheaper to produce simple, semi-finished products and then join them to form complex components with the desired graded structure through powder forging and simultaneous compaction. It is also essential that the graded structure of the semi-finished products is retained during the forming process. In this study, pre-sintered cylindrical semi-finished products consisting of identical homogeneous layers as well as graded components consisting of non-identical homogeneous layers were joined using powder forging at 1100 °C. The microstructures and densities as well as the mechanical properties of the final components were investigated. It was observed that, upon compaction, the components formed solid structures, in which the reinforcing ZrO2 particles were completely integrated within the transformation-induced plasticity steel matrix. Finally, it was confirmed that the graded structure of the semi-finished products was retained in the final components.

Innovative Metal Injection Molding (MIM) Method for Producing CoCrMo Alloy Metallic Prosthesis for Orthopedic Applications

2014 ◽  
Vol 879 ◽  
pp. 102-106
Author(s):  
Noorsyakirah Abdullah ◽  
Mohd Afian Omar ◽  
Shamsul Baharin Jamaludin ◽  
Nurazilah Mohd Zainon ◽  
Norazlan Roslani ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Injection Molding ◽  
High Performance ◽  
Slip Casting ◽  
Plastic Injection Molding ◽  
Metal Injection Molding ◽  
Powder Injection ◽  
Powder Metallurgy Process ◽  
The Cost ◽  
Plastic Injection

Powder injection molding (PIM) is a powder metallurgy process currently used for the production of complicated and near net shape parts of high performance materials [. This technique basically combines the advantages of plastic injection molding and the versatility of the conventional powder metallurgy technique. The process overcomes the shape limitation of powder compaction, the cost of machining, the productivity limits of isostatic pressing and slip casting, and the defect and tolerance limitations of conventional casting [1, 2, . According to German and Bose [, the technology of metal injection molding (MIM) is more complicated than that of the plastic injection molding, which arises from the need to remove the binder and to densify and strengthen the part. The process composed of four sequential steps: mixing of the powder and organic binder, injection molding, debinding where all binders are removed and sintering [1, 2, 3, 4]. If it necessary, secondary operations such as heat treatments after sintering can be performed [1, 2, 3, 4, .

Characterization and Properties of Iron/Silica-Sand-Nanoparticle Composites

2011 ◽  
Vol 316-317 ◽  
pp. 97-106 ◽  
Author(s):  
Tahir Ahmad ◽  
Othman Mamat
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Powder Metallurgy ◽  
Metal Matrix ◽  
Silica Sand ◽  
Particulate Composites ◽  
Powder Metallurgy Technique ◽  
Superior Mechanical Properties ◽  
Iron Based ◽  
Nanoparticle Composites

Metal matrix-particulate composites fabricated by using powder metallurgy possess a higher dislocation density, a small sub-grain size and limited segregation of particles, which, when combined, result in superior mechanical properties. The present study aims to develop iron based silica sand nanoparticles composites with improved mechanical properties. An iron based silica sand nanoparticles composite with 5, 10, 15 and 20 wt.% of nanoparticles silica sand were developed through powder metallurgy technique. It was observed that by addition of silica sand nanoparticles with 20 wt.% increased the hardness up to 95HRB and tensile strength up to 690MPa. Sintered densities and electrical conductivity of the composites were improved with an optimum value of 15 wt.% silica sand nanoparticles. Proposed mechanism is due to diffusion of silica sand nanoparticles into porous sites of the composites.

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