scholarly journals Development of new approaches to the study of pitting corrosion resistance of stainless steels obtained by selective laser melting

2019 ◽  
Vol 121 ◽  
pp. 01011
Author(s):  
Olga Parmenova ◽  
Svetlana Mushnikova ◽  
Vitaliy Bobyr ◽  
Evgeniy Samodelkin
Keyword(s):  
Corrosion Resistance ◽  
Selective Laser Melting ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Laser Scanning ◽  
Corrosion Behaviour ◽  
Steel Corrosion ◽  
Scanning Speed ◽  
Laser Melting ◽  
Initial State

This paper presents the results of comparative corrosion resistance studies of stainless steels manufactured by selective laser melting (SLM) in the initial state with subsequent heat treatment and machining. Pitting corrosion tests are carried out, according to ASTM G48 method A in 10% FeCl3·6H2O solution at elevated temperature and exposure time for 5h. The studies were performed on the AISI 321 and AISI 316L stainless steels manufactured by SLM. It was obtained that laser scanning speed decrease led to density rise by other SLM parameters being equal. Porosity affected to the stainless steel corrosion behaviour significant. Metal density decrease resulted to corrosion rate rise. Microstructure examination showed that pitting corrosion development depended on surface steel condition.

Liquation and Crystallization Cracks in Aluminum Alloy AA2024 during Selective Laser Melting

2021 ◽  
Vol 410 ◽  
pp. 203-208
Author(s):  
I.S. Loginova ◽  
N.A. Popov ◽  
A.N. Solonin
Keyword(s):  
Aluminum Alloy ◽  
Selective Laser Melting ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Melting Zone ◽  
Alloying Elements ◽  
Laser Melting ◽  
Laser Scanning Speed ◽  
Positive Effect

In this work we studied the microstructure and microhardness of standard AA2024 alloy and AA2024 alloy with the addition of 1.5% Y after pulsed laser melting (PLM) and selective laser melting (SLM). The SLM process was carried out with a 300 W power and 0.1 m/s laser scanning speed. A dispersed microstructure without the formation of crystallization cracks and low liquation of alloying elements was obtained in Y-modified AA2024 aluminum alloy. Eutectic Al3Y and Al8Cu4Y phases were detected in Y-modified AA2024 aluminum alloy. It is led to a decrease in the formation of crystallization cracks The uniform distribution of alloying elements in the yttrium-modified alloy had a positive effect on the quality of the laser melting zone (LMZ) and microhardness.

Numerical Study of Porosity Formation With Implementation of Laser Multiple Reflection in Selective Laser Melting

2019 ◽  
Author(s):  
Bo Cheng ◽  
Charles Tuffile
Keyword(s):  
Selective Laser Melting ◽  
Laser Scanning ◽  
Numerical Study ◽  
Fluid Model ◽  
Melting Process ◽  
Scanning Speed ◽  
Powder Layer ◽  
Cfd Model ◽  
Laser Melting ◽  
Porosity Formation

Abstract In selective laser melting (SLM) process, the build part quality is determined by process parameters such as laser scanning speed and power. The presence of porosity, a major printing defect that significantly affects part performance, may arise in laser melting process due to insufficient or excess energy input. The improvement of build quality heavily depends on fundamental understanding of porosity formation in the SLM process. In this study, the discrete element method (DEM) has been utilized to simulate the creation of a newly deposited powder layer. A computational fluid dynamics (CFD) model was developed to simulate the melting and solidification process of Ti-6Al-4V powders in the SLM process. The thermo-fluid model includes effect of surface tension and recoil pressure as well as laser ray multi-reflection in keyhole. The predictability of the developed CFD model has been validated against literature experimental data. It is found that the collapse of an unstable deep keyhole was responsible for the formation of pores. In addition, higher laser scanning speeds tend to form unstable melt pools, e.g., melt pool break-up.

scholarly journals In Situ Mo(Si,Al)2-Based Composite through Selective Laser Melting of a MoSi2-30 wt.% AlSi10Mg Mixture

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3720 ◽  
Author(s):  
Tatevik Minasyan ◽  
Sofiya Aydinyan ◽  
Ehsan Toyserkani ◽  
Irina Hussainova
Keyword(s):  
High Temperature ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Laser Melting ◽  
Structural Applications ◽  
Laser Scanning Speed ◽  
Fusion Approach

The laser power bed fusion approach has been successfully employed to manufacture Mo(Si,Al)2-based composites through the selective laser melting of a MoSi2-30 wt.% AlSi10Mg mixture for high-temperature structural applications. Composites were manufactured by leveraging the in situ reaction of the components during printing at 150–300 W laser power, 500–1000 mm·s−1 laser scanning speed, and 100–134 J·mm−3 volumetric energy density. Microcomputed tomography scans indicated a negligible induced porosity throughout the specimens. The fully dense Mo(Si1-x,Alx)2-based composites, with hardness exceeding 545 HV1 and low roughness for both the top (horizontal) and side (vertical) surfaces, demonstrated that laser-based additive manufacturing can be exploited to create unique structures containing hexagonal Mo(Si0.67Al0.33)2.

The Effect of Hydrogen on Pitting Corrosion of Superaustenitic and Austenitic-Ferritic Stainless Steels

2012 ◽  
Vol 326-328 ◽  
pp. 620-625 ◽  
Author(s):  
Joanna Michalska
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Corrosion Current Density ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Passive Films ◽  
Cyclic Polarization ◽  
Film Stability ◽  
Ferritic Stainless Steels

Hydrogen entering into steel affects its electrochemical properties and may enhance the susceptibility to environmental degradation. The present work has been aimed at further clarifying the effect of hydrogenation on the corrosion behaviour and passivity of highly-alloyed stainless steels. The results were discussed by taking into account hydrogen charged samples and without hydrogen. The corrosion resistance to pitting was qualified with the cyclic polarization curves. The conclusion is that hydrogen may deteriorated the passive film stability and corrosion resistance to pitting of highly-alloyed stainless steel. Furthermore, the presence of hydrogen in passive films increases corrosion current density, decreasing the potential of the film breakdown and repassivation potential. It was also found that the degree of susceptibility to hydrogen-enhanced pitting corrosion was dependent on the type of steel.

scholarly journals Selective Laser Melting of 316L Stainless Steel: Influence of Co-Cr-Mo-W Addition on Corrosion Resistance

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 597
Author(s):  
Bolin Li ◽  
Tingting Wang ◽  
Peizhen Li ◽  
Shenghai Wang ◽  
Li Wang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Selective Laser Melting ◽  
Scanning Speed ◽  
Corrosion Current ◽  
Laser Melting ◽  
Two Samples ◽  
Order Of Magnitude ◽  
The Difference ◽  
Tensile Experiment

The selective laser melting (SLM) of o-Cr-Mo-W/316L composite with 10wt% Co-Cr-Mo-W addition to 316 L stainless steel (SS) powder is produced to explore it’s the corrosion behavior. The tensile experiment of SLM composites is also measured to investigate the difference between the two samples. The optimum parameters of SLM 316 L SS and it’s composite samples are obtained by adjusting laser power and scanning speed with the relative density of 99.04 ± 0.69 and 99.15 ± 0.43. The yield strength of samples is increased from 731.96 MPa to 784.09 MPa after doping, and no obvious crack or fracture failure in the tensile samples are observed, indicating that the excellent plasticity is still maintained. The corrosion resistance of samples is improved largely with an order of magnitude lower corrosion current density than that of 316 L SS and increasing of 277 mv of epit Ep. The addition of Cr element in the doped powder contributes to the formation of the passivated film containing Cr. The different pitting corrosion pit occurs mainly around the pre-existing pores of the powder and further extends outward to form pits with the increase of voltage.

scholarly journals Modeling of Residual Stress Distribution for Components Manufactured by Selective Laser Melting

2019 ◽  
Vol 224 ◽  
pp. 05006
Author(s):  
Tong Ye ◽  
Xiaohui Jiang ◽  
Miaoxian Guo ◽  
Vladimir Kuptsov ◽  
Sergey Fedorov
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Residual Stress Distribution ◽  
Laser Melting ◽  
Laser Scanning Speed ◽  
Formed Part

In this paper, the selective laser melting (SLM) simulation analysis of components is carried out. The residual stress distribution of the formed part was predicted, and the influence of process parameters such as exposure time, laser power and laser scanning speed on the residual stress of the SLM formed part was analyzed. It was found that the residual stress concentration of the formed part was in the middle of the upper surface or the bottom surface. In addition, the laser power and the laser scanning speed have a great influence on the residual stress of the formed part. The results of this study lay a theoretical and experimental basis for the optimization of residual stress and quality control of SLM components.

scholarly journals Corrosion Resistance of Some Stainless Steels in Chloride Solutions

2017 ◽  
Vol 62 (2) ◽  
pp. 711-714
Author(s):  
D. Kasprzyk ◽  
B. Stypuła
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Potentiodynamic Polarization ◽  
Biomedical Application ◽  
Corrosion Behaviour ◽  
Immersion Test ◽  
Ringer Solution ◽  
Ferritic Stainless Steels ◽  
Chloride Solutions

AbstractThe present work compares corrosion behaviour of four types of S30403, S31603, S32615 austenitic and S32404 austenitic-ferritic stainless steels in chloride solutions (1%, 3% NaCl) and in Ringer solution, at 37°C temperature. Corrosion resistance was determined by potentiodynamic polarization measurements and a thirty day immersion test conducted in Ringer solution. The immersion test was performed in term of biomedical application. These alloy were spontaneously passivated in all electrolytes, wherein S30403, S31603 and S32404 undergo pitting corrosion. Only S32615 containing 5.5% Si shows resistance to pitting corrosion.

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