scholarly journals Production of Porous Stainless Steel using the Space Holder Method

2021 ◽  
Vol 50 (2) ◽  
pp. 507-514
Author(s):  
Koon Tatt Tan ◽  
Norhamidi Muhamad ◽  
Andanastuti Muchtar ◽  
Abu Bakar Sulong ◽  
Yih Shia Kok

Metallic foams and porous materials can be produced by various methods. Among the methods that can produce metallic foams and porous materials, powder metallurgy is a promising method. This study investigates the production of a porous stainless steel by the space holder method in powder metallurgy. A novel space holder i.e. glycine and binder consisting of polymethylmethacrylate and stearic acid are used. Different amounts of glycine are added to the mixture of stainless-steel powder and binder. Subsequently, each mixture is cold-pressed at a pressure of 9-ton m-2. The samples are sintered at 1050 and 1150 °C with holding times of 30, 60, and 90 min. The microstructures and physical and mechanical properties of the sintered samples are investigated. A porous stainless steel with porosity ranging from 30.8 to 51.4% is successfully fabricated. Results show that the glycine content and sintering parameters influence the properties of the porous stainless steel. The sintering temperature significantly affects volumetric shrinkage. Volumetric shrinkage decreases as the volume fraction of glycine increases to 30% whereas sintering temperature 1150 °C and holding time 90 min will increase the volumetric shrinkage. The compressive yield strength and corresponding elastic modulus are in the ranges of 22.9 to 57.6 MPa and 6.3 to 26.8 GPa, respectively. The samples produced have potential biomedical applications because their mechanical properties, yield strength and elastic modulus match those of human bones.

2019 ◽  
Vol 16 (2) ◽  
pp. 183-188
Author(s):  
Shailendra Joshi

Stainless steel has an excellent mechanical property as well as high corrosion resistance. Stainless steel foams, therefore, seemed like an attractive material for impact energy absorption applications where damping capability is required such as in vehicles and buildings. Also when stainless steel foam is produced as stainless steel foam, the material density will be reduced thus the resulting foam will be a combination of light weight and high strength that can also be used in high strength applications. In our analysis, we tried to produce stainless steel foam through powder metallurgy in order to control mechanical properties in a better manner compared to the casting method. Also, we try to compare the pore morphology in foams on changing the space holder from accicular urea to crushed urea using FE-SEM. The properties of stainless steel foam, to a large extent, are found to depend on the arrangement of the pores which is decided by the space holder utilized during its synthesis using powder metallurgy route. The stainless steel obtained using acicular carbamide as space holder is found to possess acicular or irregular pores whereas those produced with crushed urea as space holder possesses nearly circular holes. Also, the previous foams are found to have better mechanical properties contributing towards more useful metallic foam.


Author(s):  
Zhiwei Chen ◽  
Caifu Qian ◽  
Guoyi Yang ◽  
Xiang Li

The test of austenitic stainless steel specimens with strain control mode of pre-strain was carried out. The range of pre-strain is 4%, 5%, 6%, 7%, 8%, 9% and 10% on austenitic stainless steel specimens, then tensile testing of these samples was done and their mechanical properties after pre-strain were gotten. The results show that the pre-strain has little effect on tensile strength, and enhances the yield strength more obviously. According to the experimental data, we get a relational expression of S30408 between the value of yield strength and pre-strain. We can obtain several expressions about different kinds of austenitic stainless steel by this way. It is convenient for designers to get the yield strength of austenitic stainless steel after pre-strain by the value of pre-strain and the above expression.


Author(s):  
J.A. Brogan ◽  
C.C. Berndt ◽  
A. Claudon ◽  
C. Coddet

Abstract The mechanical properties of EMAA copolymer are dependent upon the thermal spray processing parameters. The parameters determine coating temperatures which, in turn, affects the microstructure. If the deposition temperature is too low, (104 °C for PFl 13 and 160 °C for PFl 11) coatings have low strengths and low energy to break values. Increased coating temperatures allow the particles to fully coalesce resulting in maximized strength and elongation to break. However, at 271 °C, PFl 11 had visible porosity which decreased both strength and elastic modulus. Pigment acts as reinforcement in the sense that the modulus increased but the elongation to break decreased, thus reducing the energy to break. Water quenching reduces the elastic modulus and yield strength, but increases the elongation to break for both EMAA formulations. The mechanical properties of post consumer commingled plastic and PCCP / EMMA blends improved if the recycled plastic was pre-processed by melt-compounding. Melt compounding increased the strength and toughness by improving the compatibility among the various polymer constituents. The addition of PCCP increases the modulus and yield strength of ethylene methaciylic acid copolymer.


2021 ◽  
Vol 105 ◽  
pp. 8-16
Author(s):  
Guttikonda Manohar ◽  
Krishna Murari Pandey ◽  
Saikat Ranjan Maity

Metal matrix composites attain a significant position in Industrial, defense, structural and automobile applications. To amplify that strategy there is a need to find out the conditional behavior of the composites and enhancing the properties will be mandatory. The present work mainly investigates on the effect of processing parameters like densification rates, sintering temperature, reinforcement content on the microstructure, mechanical properties of the Al7175/B4C composite material fabricated by mechanical milling and powder metallurgy techniques. Results show there is a grain size reduction and refinement in the composite material through ball milling operations and along with that increasing B4C content in the composite powders make milling conditions very effective. Increasing the sintering temperature results in a consistent grain growth along with that porosity level decreases up to a limit and then attain a steady state, the strength of the composites increases with compaction pressures but reinforcements content effects the strength of the material by losing its ductility making it brittle.


2013 ◽  
Vol 683 ◽  
pp. 145-149
Author(s):  
Xing Lei Hu ◽  
Ya Zhou Sun ◽  
Ying Chun Liang ◽  
Jia Xuan Chen

Monte Carlo (MC) method and molecular dynamics (MD) are combined to analyze the influence of ageing on mechanical properties of machined nanostructures. Single crystal copper workpiece is first cut in MD simulation, and then the machined workpiece is used in MC simulation of ageing process, finally the tensile mechanical properties of machined nanostructures before and after ageing are investigated by MD simulation. The results show that machining process and ageing have obvious influence of tensile mechanical properties. After machining, the yield strength, yield strain, fracture strain and elastic modulus reduce by 36.02%, 28.86%, 20.79% and 7.16% respectively. However, the yield strength, yield strain and elastic modulus increase by 4.84%, 1.41% and 1.02% respectively, fracture strain reduce by 24.53% after ageing process. To research the ageing processes of machined nanostructures by MC simulation is both practical and meaningful.


2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Tan Koon Tatt ◽  
Norhamidi Muhamad ◽  
Andanastuti Muchtar ◽  
Abu Bakar Sulong ◽  
Heng Shye Yunn

Metal foam has emerged as a new class material that can be used in structural and functional applications. Because of its excellent mechanical and physical properties, it has been extensively used in aerospace, automotive and medical industries. There are several ways to produce the metal foams. In this study, a net shape foaming technology namely Metal injection moulding-Powder space holder method (MIM-PSH) was used to produce the porous metal. A novel space holder, glycine was mixed with the water atomized stainless powder, palm stearin and polyethylene binder. Rheological behaviours of the feedstocks were fully investigated. The volume fraction of glycine was varied for 50% and 70%, to study its effect on the rheological properties. The results showed that all feedstocks exhibit shear thinning behaviour. As the volume fraction of space holder increased, the viscosities of feedstocks are increased. The activation energy, E is proportional to the amount of space holder used. All feedstocks are found to be suitable for MIM-PSH to produce the porous stainless steel.


2019 ◽  
Vol 950 ◽  
pp. 65-69
Author(s):  
Sun Fei ◽  
Xu Cheng

In order to study the effect of temperature on the mechanical properties of H90 copper strip material, the H90 copper strip test pieces were heated to different temperatures (20~600 °C) for tensile test; the yield strength, tensile strength, elastic modulus and elongation of H90 copper strip at different temperatures were obtained. Based on the test results, the empirical models of yield strength, tensile strength, elastic modulus of H90 copper strip at high temperature were established; the test showed that, with the increase of temperature, the yield strength, tensile strength and elastic modulus of H90 copper strip decreased greatly, and the elongation after fracture first increased-decreased-increased at 20~600 °C. The study results in this paper provide basic material data for analyzing the effect of temperature on the continuous firing of firearms and other weapons.


2017 ◽  
Vol 863 ◽  
pp. 26-32
Author(s):  
Ming Zhou Su ◽  
Hui Meng Wang ◽  
Chang Chen

Porous irons with only micropores were produced through powder metallurgy route. Corn starch of small particle size (5-15μm) was utilized to regulate the densification of green compacts. The structural and mechanical properties of porous irons sintered at different temperatures were evaluated. The porosities increased with increasing the starch content, which reduced compressive strength and increased volumetric shrinkage. The compressive yield stress increased with increasing sintering temperature. It was also found that the effect of sintering temperature on the microstructure and compressive properties was more obvious when green compacts were less densified. Moreover, volumetric shrinkage of porous irons without adding starch remains in a quite low level for different sintering temperatures.


2019 ◽  
Vol 944 ◽  
pp. 193-198
Author(s):  
Tian Yi Wang ◽  
Ren Bo Song ◽  
Heng Jun Cai ◽  
Jian Wen ◽  
Yang Su

The present study investigated the effect of cold rolling reduction on microstructure and mechanical properties of a 204C2 Cr–Mn austenitic stainless steel which contained 16%Cr, 2%Ni, 9%Mn and 0.083 %C). The 204C2 austenitic stainless steels were cold rolled at multifarious thickness reductions of 10%, 20%, 30%,40% and 50%, which were compared with the solution-treated one. Microstructure of them was investigated by means of optical microscopy, X-ray diffraction technique and scanning electron microscopy. For mechanical properties investigations, hardness and tensile tests were carried out. Results shows that the cold rolling reduction induced the martensitic transformation (γ→α ́) in the structure of the austenitic stainless steel. With the increase of the rolling reduction, the amount of strain-induced martensite increased gradually. Hardness, ultimate tensile strength and yield strength increased with the incremental rolling reduction in 204C2 stainless steels, while the elongation decreased. At the thickness reduction of 50%, the specimen obtained best strength and hardness. Hardness of 204C2 stain steel reached 679HV. Ultimate tensile strength reached 1721 MPa. Yield strength reached 1496 MPa.


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