This paper reports nano-structured SiO2-TiO2 coatings using the sol-gel technique on 316L STEEL substrates. Nanoindentation, surface analysis and corrosion resistance tests were performed on different samples. The nanomechanical tests allowed to compare the uncoated STEEL samples (Eavg = 193. 24GPa and the mean hardness of 2. 63GPa and coated STEEL samples (Eavg = 287. 38GPa and mean hardness of 5. 74GPa), resulting in an improvement of the resistance and modulus of elasticity of the coated STEEL substrates. From a surface analysis an average thickness of 1. 12μ m was obtained in the coated samples, presenting a dense and consolidated coating. Polarization resistance (PR) and electrochemical impedance spectroscopy (EIS) tests were performed. The PR tests showed a resistance of 2. 11  105 (Ω cm2) for the uncoated STEEL, while the coated STEEL showed a resistance of 3. 46  105 (Ω cm2), indicating an increase in resistance compared to the bare STEEL. The EIS tests showed greater resistance by the coated STEEL (5. 8 105 (Ω cm2)) compared with the bare STEEL (2. 8 105 (Ω cm2)). The effects of the electrolyte in both conditions were observed by SEM after immersion for 24 h, showing pitting by the bare STEEL and good protection by the coated STEEL.

This study was a preliminary study on flame spray coating with hydroxyapatite (HAp). Coating is one of the technique to improve metal resistance to corrosion. In this study, flame spray coating using HAp was performed on STAINLESS STEEL 316 L as a material for medical devices. This synthetic compound contains elements which are biocompatible and bioactive in human body where they can stick to body tissues or muscles.HAp has been extensively used as a bone substitute because of its crystal structure, biocompatibility and osteoconductive nature. In this study, 316L SS was coated by HAp using flame spray method with varied oxygen flowrate and air pressure. The result of this study showed that the air pressure of 1 bar and oxygen flowrate of 25 l/min had the thickest coating which was 123.5μm and the lowest corrosion rate which was 0.0261 mm/year. The air pressureof 3 bar and oxygen flowrate of 35 l/min produced the lowest thickness which was 32.5μm and the highest corrosion rate which was 0.0761 mm/year. The use of high air pressure and oxygen flowrate decreased the coating thickness and the corrosion rate. The result revealed that flame spray method was effective to be used to coat HAp on 316L SS.

Objective(s): In Indonesia, the incidence of bone injuries as a result of traffic accidents is quite high. This necessitates the use of bone implants, which are frequently made of STAINLESS STEEL 316L ( SS316L). The probability of contracting an infection when implanting an SS316L implant has been increasing. Infection due to implant placement is called osteomyelitis which is bone inflammation caused by biofilms formed by pyogenic bacteria. Biofilms can be prevented by giving antibacterial agents. This research aims to explore silver nanoparticles (AgNPs) as an antibacterial agent in SS316L implants. Methods: AgNPs are synthesised using the Gallic acid reduction technique. AgNPs solution added with gelatin was misted on SS316L with five different precursor concentrations (0. 1, 1, 10, and 100 mM) using the airbrush spray coating approach with a distance of 20 cm between the nozzle and the substrate and a pressure of 40 psi. Results: AgNPs solutions produced from various concentrations of AgNO3 precursors have a broad spectrum of excitation maximums (λ max = 401. 5 nm-424. 5 nm) and crystallite size in the range of 0. 97-4. 88 nm. The AgNPs layer on SS316L was characterized for their crystalline phase, crystal size, and antibacterial activity. It has a cubic structure with a phase fraction of 6. 5-19%. The inhibition zone radius for AgNPs coated samples is in the range of 12-16 mm. The combination coating of AgNPs (10 mM) and gelatin layer seemed to have the best antibacterial ability, with an inhibition zone diameter of 16. 63 mm. Conclusions: It is imperative to generate concentration variation of the 10 mM AgNPs precursor-Gelatin to be used to as coating layer on the SS316L restorative surface.

Forming limit diagram (FLD) is composed of negative and positive minor strain with respect to major strain, which occurs at directional zero strain with the critical thickness of sheet metal. The negative minor strain region of FLD is predicted by localized necking. However, there is no directional zero strain in the positive minor region of FLD which could be predicted with the help of Marcinaik-Kuczynski assumption. The present work aims to determine the stretch ability in terms of limiting strain of Austentic STAINLESS STEEL 316L using M K analysis and hemi spherical dome stretching. Strain hardening exponent was derived from uni axial tensile test of Austentic STAINLESS STEEL 316L. C++ program was developed to predict the theoretical FLD and the results were compared with the experimental value. The limiting strain of material is found as 0.4 in the experimental and Marcinaik - Kuczynski analysis. Fractography shows the large amount of cleavage fracture and becomes an evidence for cleavage initiating due to other inclusions.

Nanostructured alumina thin films were coated on STAINLESS STEEL by Sol-Gel dip coating method. In order to prevent crack formation, Al2O3 films were kept in a solvent bath immediately after coating to reduce the rate of drying. Effects of calcination temperature and withdrawal speed on structural properties were analyzed using XRD and SEM. Topography and thickness of coatings were analyzed by AFM. Effects of the above parameters on anticorrosion performance of coats have been evaluated through electrochemical polarization technique. The results indicated that the optimum calcination temperature to achieve the best corrosion protection was 400oC. The thickness of one time coating with 1mm/s withdrawal speed was about 146 nm.

Damage is a progressive physical process, which at last leads to failure. During the damage process, material experiences some changes such as nucleation, growth, and coalescence of microscopic voids and microcracks. If the metal material is under the plastic strain, some defects like voids and microcracks are created. Increasing the plastic strains, these defects develop and eventually crack is created in the material which causes fracture in it. Therefore, measuring the damage is very important and various methods have been proposed to determine the damage in materials yet. In this paper first, different methods of estimating the ductile damage are presented and then, ductile damage for STAINLESS STEEL 316L is determined, using the measurement of elasticity modulus and also measurement of velocity of ultrasonic wave propagation methods. Finally, value of critical ductile damage parameter for the material is calculated by each of these methods and compared.

In this research, the effects of heat treatment on the the microstructure and mechanical properties of 316L STAINLESS STEEL coatings sprayed by flame spraying process was studied. Coatings have been heat-treated at a range of temperatures between 800 and 1150oC. The microstructure characteristics of the deposits were studied using the combined techniques of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, the mechanical properties were tested using the adhesion strength and microhardness tests. Results indicate that by heat-treating the coatings at a temperature of 800 and 950oC, it is possible to achieve higher adhesion strength and hardness values. This was attributed to the improvements in the coating microstructure during the heat-treatment, which resulted in an improvement in coating's mechanical properties through the formation of intermediate phases, and the establishment of metallurgical bonding within the coating microstructure. However, the results also inidate that by increasing the temperature to higher than 1150oC, there was a reduction in the coating's mechanical properties. This could be attributed to the grain growth, and coarsened precipitation of the equilibrium phases from supersaturated solid solutions.

In the present work, deoxidation and refining of 316LVM STEEL (Low carbon Vacuum Melted) during the vacuum induction melting process was studied. This grade of STAINLESS STEEL is one of the most important materials in medical applications. Vacuum deoxidation by carbon is the first stage of 316LVM STAINLESS STEEL production process. In this stage, aluminum must be absent to avoid killing the C-O reaction. Deoxidation product in the VIM process is in gaseous state which is tapped by vacuum pump system. For this reason, vacuum deoxidation by carbon is the best method for refining 316LVM STEEL. Vacuum induction melting has no significant effects on reduction of sulfur and phosphorus. After deoxidation in vacuum by carbon, addition of Al+Ca/Si is the best way for reducing the oxygen and increasing the STEEL cleanness.

In the TIG-MIG hybrid welding, higher weld efficiency and better weld quality are obtained with respect to each individual TIG and MIG welding methods. Moreover, in this method, the MIG arc is more stable in pure argon shielding gas. Therefore, in this study, the influence of TIG-MIG hybrid welding parameters on the welds appearance quality and welds depth to width ratio of a 316L austenitic STAINLESS STEEL was investigated using optimum parameters of Taguchi design of experiments (DOE). Microstructure of the heat affected zone (HAZ) obtained from the hybrid welding was compared with those of each individual MIG and TIG welding techniques under equal heat-input condition. The results indicated that the most important parameter in the hybrid method to obtain the best appearance quality and the highest depth to width ratio is the distance between the two arcs. The MIG and TIG currents are the next influencing parameters. The width of HAZ and the size of constituent grains in hybrid welding with optimum parameter, were smaller than those of each individual TIG and MIG processes due to the higher associated cooling rate in the hybrid welding technique.

In this paper, the corrosion behavior of STAINLESS STEEL 316L was evaluated in used catalyst solution in Sulfiran plant in temperature range of 35-45oC. The electrochemical techniques consisted of polarization curves and electrochemical impedance spectroscopy (EIS) were used in laboratory tests. It was found that the corrosion rate of STAINLESS STEEL 316L alloy was less than 1 mpy in this process. In the meantime, there was low possibility of pitting corrosion on STAINLESS STEEL 316L. The weight loss technique was used for the determination of corrosion rate in pilot tests. In addition, surface analysis techniques such as XRD, XRF, and SEM were applied in this research. The evaluations of microstructure of STAINLESS STEEL 316L were also carried out. The results of pilot tests confirmed the findings of laboratory tests. While inclusions were present in alloy STAINLESS STEEL 316L microstructure, the investigation of metallurgical aspect of the mentioned alloy showed negligible uniform corrosion damage.