An influence of the SS316L powder particle shape to the densification of metal injection moulding (MIM) compact

Metal injection molding (MIM) has acquired increasing importance as a production technique for small, complex stainless steel components [1, 2]. Sintering is critical for determining the final quality of the parts produced by MIM. Because high sintered density is imperative for good mechanical properties and corrosion resistance, achieving full or near-full density has been a major objective of sintering [3]. Therefore, most research on 316L stainless steel sintering to date has focused on the sintering behavior of the molded parts especially for gas-atomised powder in argon environment [3-6]. An understanding of the factors influencing densification of stainless steels is important as over 50% of the injection molded and sintered components are made from stainless steel compositions [7]. In a metal injection molding (MIM) process, gas-atomised powder is generally used due to their high packing density and associated feedstock rheology. The sintered components exhibit mechanical and corrosion properties similar or superior to that of wrought material. Water-atomised powders in MIM can be economical and have an improvement in shape retention during debinding and sintering. However, their use comes with a penalty of lower powder loading and sintered density, with a corresponding degradation in the mechanical and corrosion properties. Studies reveal that injection molded and sintered components using water-atomised 316L stainless steel powders have a residual porosity of 3–5% for similar particle characteristics and sintering conditions as that of gas-atomised powders [5]. This article investigates a densification of SS316L gas and wateratomised compact sintered in high vacuum environment at temperature ranging from 1340 to 1400 °C

Powder injection moulding, its outstanding features an development

Metal Injection moulding (MIM) is a development of the traditional powder metallurgy (PM) process and is rightly regarded as a branch of that technology. Th e standard PM process is to compact a lubricated powder mix in a rigid die by uniaxial pressure, eject the compact from the die, and sinter it. It is a novel process which combines the plastic injection moulding with the conventional powder metallurgy technology. Quite complicated shapes can be and are regularly being produced by the million, but there is one significant limitation as regards to shape. In the MIM process, there are four processing steps: (1) mixing – compounding the metal powder and organic binder into feedstock; (2) moulding – shaping the parts from feedstock as in plastic inject ion moulding; (3) debinding – removing the binder in the moulded parts by pyrolysis or solvent soaking; (4) sintering –densifyi ng the debound parts to a high final density

Metal Injection Moulding (MIM) feedstock preparation with dry and wet mixing : a rheological behaviour investigation

Metal injection molding (MIM) is an advanced technology for processing net-shaped components that is experiencing commercial acceptance. In this process, a metal powder is mixed with an organic binder to produce a mixture, or feedstock, which has sufficiently low enough viscosity th at can be molded using a high- pressure screw injection-molding machine. Once molded, the binder is removed from the components. This step is called debinding and can be performed by different techniques such as solvent debinding, thermal debinding, catalytic debinding, etc. [3]. In order to improve the brown part mechanical properties, the part will be sintered

The influence of SS316l foam fabrication parameter using powder metallurgy route

Metal foams are widely produced by using different techniques such as compaction and replication method. In this study, slurry method also known as replication method has been used to produce SS316L foams. SS316L powders (50wt% and 60wt%) were mixed with the binders and distilled water by using mechanical stirrer. Polyethylene Glycol (PEG) and Carboxyl Methyl Cellulose (CMC) were used as binders. Polyurethane (PU) foam was used as scaffold and dipped into SS316L slurry then dried in room temperature for 24 hours. Sintering process has been done in two different temperatures which were 1200oC and 1300oC in vacuum furnace. The morphological study was performed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX). The SEM micrograph showed that the cells were interconnected and the structures become denser as the sintering temperature increase. The average pores size is ranging from 252.8 μm-353.8 μm, while strut size ranging from 50.2 μm -79.9 μm based on SEM micrograph analysis. The elemental analysis from EDX showed the element presence in the SS316L foam remain from SS316L powder which are Chromium (Cr), Nickel (Ni), Molybdenum (Mo), Cooper (Cu), Nitrogen (N2), Sulphur (S) and Silicon (Si). Higher sintering temperature contributes better grain growth between particles where the point-contact between the particles expanded and disappear the small pores

Microstructure, hardness and corrosion behavior of gas tungsten arc welding clad Inconel 625 super alloy over A517 carbon steel using ERNiCrMo3 filler metal

In this study, Inconel 625 coating was deposited on the surface of A517 quenched and tempered low-alloy A517 steel using gas tungsten arc welding (GTAW) in order to increase the service life of the A517 substrate. For this purpose, Inconel 625 coating was deposited on steel surface by applying ERNiCrMo3 filler at different welding currents of 80, 100 and 120 A. The results showed that the microstructure of Inconel 625 coating consisted of a fully austenitic phase which was solidified having dendritic morphology, while A517 was found to be tempered martensitic. The average hardness of Inconel 625 coatings deposited at different welding currents was more than 230 HV. Evaluation of corrosion behavior also illustrated a better corrosion resistance of Inconel 625 coating than A517 base metal. The corrosion rate of Inconel 625 coating in 80 A, 100 A and 120 A samples was 0.435, 0.143 and 0.165 mpy, respectively, which were negligible in comparison with that of A517 steel (24.2 mpy)