scholarly journals Additive Manufacturing of AISI 420 Stainless Steel: processes validation, defects analysis and mechanical characterization in different process and post-process conditions.

2021 ◽  
Author(s):  
Erica Liverani ◽  
Alessandro Fortunato
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Process Parameters ◽  
High Hardness ◽  
Industrial Applications ◽  
Production Cycle ◽  
Process Conditions ◽  
Post Process ◽  
Aisi 420 ◽  
Defects Analysis

Abstract Stainless steel (SS) alloys produced by Laser-based Powder Bed Fusion (LPBF) process offers comparable and sometime improved mechanical properties respect to conventionally processed materials. Some of these steels have been extensively studied in the last decade, however additively manufactured martensitic SS, as AISI 420, need further research in characterizing their post built quality and mechanical behaviour. This lack of information on martensitic SS is not consistent with their growing demand in the automotive, medical and aerospace industries due to their good corrosion resistance, high hardness and good tensile properties. Selection of the appropriate process parameters and post treatments plays a fundamental role in determining final properties. For this reason, the effect of LPBF process parameters and different heat treatments on density, defects characteristics and location, roughness and mechanical properties of AISI 420 were investigated in this paper. A first experimental campaign was carried out to establish different set of suitable process parameters for industrial applications. Starting from this result, the detected defects properties was investigated by Computed Tomography (CT) scans. Dimensions, sphericity and distributions of defects inside the volume were analysed and compared between samples manufactured with different parameters. In the second part of the paper, the influence of process and post process conditions on mechanical properties was investigated. The final presented results establish a correlation between the involved production cycle and the resulting properties of LPBF AISI 420 specimens.

scholarly journals Additive manufacturing of AISI 420 stainless steel: process validation, defect analysis and mechanical characterization in different process and post-process conditions

2021 ◽  
Author(s):  
Erica Liverani ◽  
Alessandro Fortunato
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Process Parameters ◽  
High Hardness ◽  
Industrial Applications ◽  
Production Cycle ◽  
Process Conditions ◽  
Post Process ◽  
Aisi 420 ◽  
Lack Of Information

AbstractStainless steel (SS) alloys produced by laser-based powder bed fusion (LPBF) offers comparable and sometime superior mechanical properties compared to conventionally processed materials. Some of these steels have been extensively studied over the last decade; however additively manufactured martensitic SS, such as AISI 420, need further research in characterizing their post-built quality and mechanical behaviour. This lack of information on martensitic SS is not consistent with their growing demand in the automotive, medical and aerospace industries due to their good corrosion resistance, high hardness and good tensile properties. Selection of the appropriate process parameters and post treatments plays a fundamental role in determining final properties. For this reason, the effect of LPBF process parameters and different heat treatments on density, defect characteristics and locations, roughness and mechanical properties of AISI 420 were investigated in this paper. A first experimental campaign was carried out to establish a set of suitable process parameters for industrial applications. Starting from this result, detected defect properties were investigated by computed tomography (CT) scans. Dimensions, sphericity and distributions of defects inside the volume were analysed and compared between samples manufactured with different parameters. In the second part of the paper, the influence of process and post-process conditions on mechanical properties was investigated. The final presented results establish a correlation between the employed production cycle and the resulting properties of LPBF AISI 420 specimens.

Material-Specific Phenomena and Developing Higher Yield Process Parameters in Selective Laser Melting of 17-4 PH Stainless Steel

2021 ◽  
Author(s):  
EVREN YASA ◽  
İlker Atik ◽  
İpek Kandemir
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Chemical Composition ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Process Development ◽  
Industrial Applications ◽  
Full Density ◽  
Laser Melting ◽  
Quality Material

Abstract Although Selective Laser Melting has become attractive in industrial applications seeking a high geometrical complexity with short lead times and customization, some bottlenecks still exist for wider adoption. Build rate is one of them while the high number of process parameters and their interactions easily exceeding hundreds which affects the part performance is the second. The machine manufacturers supply parameter sets generally optimized for maximum density leading to good mechanical properties. However, other factors need to be considered in process development. This study aims at increasing the build rate of at least 2 times for 17-4 PH stainless steel without any significant effect on the density, surface quality, material composition, mechanical properties and residual stresses. The results show an excessive ultimate tensile strength to yield strength ratio in comparison to reported literature which is attributed to the double yield phenomenon mainly attributed to the phases present in the microstructure as a result of powder chemical composition and processing gas. Thus, it is concluded that powder chemical composition and processing gas are much more effective on the outcome while the process parameters with an increased build rate do not significantly change the results provided that almost full density is reached.

Effects of Sintering Variables on the Physical and Mechanical Properties of Metal Injection Molding Molded 17-4 PH Stainless Steel

2021 ◽  
Vol 1028 ◽  
pp. 403-408
Author(s):  
Apang Djafar Shieddieque ◽  
Shinta Virdhian ◽  
Moch Iqbal Zaelana Muttahar ◽  
Muhammad Rafi Muttaqin
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Injection Molding ◽  
Relative Density ◽  
Physical And Mechanical Properties ◽  
High Hardness ◽  
Argon Atmosphere ◽  
Metal Injection Molding ◽  
Manufacturing Method ◽  
Small Complex

Metal injection molding (MIM) is a near net shape manufacturing technique for producing small, complex, precision parts in mass production. MIM process is manufacturing method that combines traditional shape-making capability of plastic injection molding and the materials flexibility of powder metallurgy. The process consists of the following four steps: mixing of metal powder and binder, injection molding to shape the component, debinding to remove the binder in the component, sintering to consolidate the debound parts. In this research, the physical and mechanical properties of metal injection molded 17-4 PH stainless steel were investigated with the variation of sintering temperatures (1300 °C - 1360 °C) and atmosphere conditions (argon and vacuum conditions). The relative density, microstructure, distortion, and hardness are measured and analyzed in this study. The results show that highest relative density of 87%, relative homogeneous shrinkage and high hardness are achieved by sintering at 1360 °C for 1.5 hours and argon atmosphere. At the same sintering temperature and time, sintering in vacuum shows lower relative density (81%) than that in argon condition due to pores growth. The pore growths were not observed in the argon atmosphere. It can be concluded that sintering stages more rapidly under vacuum condition. The hardness measurements result also showed that high hardness is obtained by high density parts. The optimum average hardness obtained in this study is 239 HV. However, the hardness properties results are still lower than 280 HV according to MPIF Standard 35 for MIM parts.

Prediction model for the mechanical properties of compacted poplar powder generated via hot-pressing

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 4947-4962
Author(s):  
Jin Yan ◽  
Jianan Liu ◽  
Liqiang Zhang ◽  
Zhili Tan ◽  
Haoran Zhang ◽  
...  
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Network Model ◽  
Process Parameters ◽  
Neural Network Model ◽  
Hot Pressing ◽  
Process Conditions ◽  
Wood Powder ◽  
Single Factor ◽  
The Relationship

The influence of the process parameters on the mechanical properties of compact wood powder generated via hot-pressing was analyzed through a single-factor experiment. The mechanical properties exhibited a nonlinear trend relative to the process conditions of hot-pressed compact wood powder. The relationship models between the process parameters and the mechanical properties for the compact wood powder were established by applying a multiple regression analysis and neural network methods combined with data from an orthogonal array design. A comparison between experimental and predicted results was made to investigate the accuracy of the established models by applying several data groups among the single-factor experiments. The results showed that the accuracy of the neural network model in terms of predicting the mechanical properties was greater compared with the multiple regression model. This demonstrates that the established neural network model had a better prediction performance, and it can accurately map the relationship between the process conditions and the mechanical properties of the compact wood powder.

scholarly journals Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

2014 ◽  
Vol 8 (3) ◽  
pp. 156-159 ◽  
Author(s):  
Magdalena Łępicka ◽  
Małgorzata Grądzka-Dahlke
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Degradation Products ◽  
Plasma Nitriding ◽  
Electrochemical Corrosion ◽  
Industrial Applications ◽  
Process Conditions ◽  
Corrosion Properties ◽  
Dental Instruments ◽  
Increased Risk

Abstract Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18) stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively) in two different temperature ranges (380 or 450°C) specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

scholarly journals Microstructure and mechanical properties relationship of additively manufactured 316L stainless steel by selective laser melting

2019 ◽  
Vol 5 ◽  
pp. 23 ◽  
Author(s):  
Anne-Helene Puichaud ◽  
Camille Flament ◽  
Aziz Chniouel ◽  
Fernando Lomello ◽  
Elodie Rouesne ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Hot Isostatic Pressing ◽  
Tensile Tests ◽  
Industrial Applications ◽  
Added Value ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties

Additive manufacturing (AM) is rapidly expanding in many industrial applications because of the versatile possibilities of fast and complex fabrication of added value products. This manufacturing process would significantly reduce manufacturing time and development cost for nuclear components. However, the process leads to materials with complex microstructures, and their structural stability for nuclear application is still uncertain. This study focuses on 316L stainless steel fabricated by selective laser melting (SLM) in the context of nuclear application, and compares with a cold-rolled solution annealed 316L sample. The effect of heat treatment (HT) and hot isostatic pressing (HIP) on the microstructure and mechanical properties is discussed. It was found that after HT, the material microstructure remains mostly unchanged, while the HIP treatment removes the materials porosity, and partially re-crystallises the microstructure. Finally, the tensile tests showed excellent results, satisfying RCC-MR code requirements for all AM materials.

scholarly journals Effects of Low-Temperature Tempering on Microstructure and Properties of the Laser-Cladded AISI 420 Martensitic Stainless Steel Coating

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 451 ◽  
Author(s):  
Hongmei Zhu ◽  
Yongzuo Li ◽  
Baichun Li ◽  
Zhenyuan Zhang ◽  
Changjun Qiu
Keyword(s):  
Stainless Steel ◽  
Low Temperature ◽  
Martensitic Stainless Steel ◽  
Testing Machine ◽  
Industrial Applications ◽  
Slight Reduction ◽  
Micro Hardness ◽  
Microstructure And Properties ◽  
Steel Coating ◽  
Aisi 420

Post-treatment is crucial to improve the comprehensive performance of laser-cladded martensitic stainless steel coatings. In this work, a low-temperature tempering treatment (210 °C), for the first time, was performed on the laser-cladded AISI 420 martensitic stainless steel coating. The microstructure and properties of the pre- and post-tempering specimens were carefully investigated by XRD, SEM, TEM, a micro-hardness tester, a universal material testing machine and an electrochemical workstation. The results show that the as-cladded AISI 420 stainless steel coating mainly consisted of martensite, austenite, Fe3C and M23C6 carbides. The phase constituent of the coating remained the same, however, the martensite decomposed into finer tempered martensite with the precipitation of numerous nano-sized Fe3C carbides and reverted austenite in the as-tempered specimen. Moreover, a slight reduction was found in the micro-hardness and tensile strength, while a significant increase in elongation was achieved after tempering. The fractography showed a transition from brittle fracture to ductile fracture accordingly. The as-tempered coating exhibited a striking combination of mechanical properties and corrosion resistance. This work can provide a potential strategy to enhance the overall properties of the laser-deposited Fe-based coating for industrial applications.

Characterization of Dissimilar Welded Joints Between Austenitic and Duplex Stainless Steel Grades for Liquid Tank Applications

2018 ◽  
Author(s):  
G. Ubertalli ◽  
M. Ferraris ◽  
P. Matteis ◽  
D. Di Saverio
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Welded Joints ◽  
Industrial Applications ◽  
Duplex Stainless Steels ◽  
Steel Pipes ◽  
Steel Grades ◽  
Welding Processes

Lean duplex stainless steels have similar corrosion and better mechanical properties than the austenitic grades, which ensure their extensive spreading in industrial applications as a substitute of austenitic grades. In the construction of liquid tanks, however, it is often necessary to weld such steels with a range of fittings which are commonly fabricated with austenitic stainless steel grades. Therefore, this paper examines dissimilar welded joints between LDX 2101 (or X2CrMnNiN22-5-2) lean duplex stainless steels plates and austenitic stainless steel pipes, carried out by different arc welding processes. The investigation focuses on the correlation between the welding procedures and the microstructural and mechanical properties of the welded joints.

Microstructure and Mechanical Properties of Electron Beam Deposits of AISI 316L Stainless Steel

2011 ◽  
Author(s):  
Liang Wang ◽  
Sergio D. Felicelli ◽  
Jacob Coleman ◽  
Rene Johnson ◽  
Karen M. B. Taminger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Electron Beam ◽  
Process Parameters ◽  
316L Stainless Steel ◽  
Beam Current ◽  
Aisi 316L ◽  
Translation Speed ◽  
Aisi 316L Stainless Steel ◽  
Microstructure And Mechanical Properties

Electron beam freeform fabrication (EBF3) is a process that uses an electron beam and wire feedstock to fabricate metallic parts inside a vacuum chamber. In this study, single and multiple layer linear deposits of AISI 316L stainless steel were produced with the EBF3 machine at NASA Langley Research Center (LaRC). EBF3 process parameters, including beam current, translation speed, and wire feed rate, were investigated in order to consider their effects on the resulting steel deposit geometry, microstructure and mechanical properties. Results indicate that the EBF3 process can produce pore-free, fully dense material within the range of process parameters used in this study. The electron beam deposited stainless steel has a solidification microstructure with fine columnar grains within most parts of the deposit due to the high cooling rate during the deposition, with some small homogeneous equiaxed grains at the top of the deposit. The mechanical properties of the deposits are comparable to those of wrought metal, which is attributed to the homogeneous fine-grained microstructure.

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