Stainless Steel AISI Research Articles

Particle-Based Numerical Simulation Study of Solid Particle Erosion of Ductile Materials Leading to an Erosion Model, Including the Particle Shape Effect.

Solid particle erosion inevitably occurs if a gas–solid or liquid–solid mixture is in contact with a surface, e.g., in pneumatic conveyors. Having a good understanding of this complex phenomenon enables one to reduce the maintenance costs in several industrial applications by designing components that have longer lifetimes. In this paper, we propose a methodology to numerically investigate erosion behavior of ductile materials. We employ smoothed particle hydrodynamics that can easily deal with large deformations and fractures as a truly meshless method. In addition, a new contact model was developed in order to robustly handle contacts around sharp corners of the solid particles. The numerical predictions of erosion are compared with experiments for stainless steel AISI 304, showing that we are able to properly predict the erosion behavior as a function of impact angle. We present a powerful tool to conveniently study the effect of important parameters, such as solid particle shapes, which are not simple to study in experiments. Using the methodology, we study the effect of a solid particle shape and conclude that, in addition to angularity, aspect ratio also plays an important role by increasing the probability of the solid particles to rotate after impact. Finally, we are able to extend a widely used erosion model by a term that considers a solid particle shape.

Finite Element Analysis of Camshaft Using Inventor Software

Abstract: In this work the 3D model of the camshaft was done using Autodesk Inventor version 2021 with the literature data and finite element analysis is performed by applying restrictions and loads conditions, first by the absence of the torque and then by applying the torque. Three materials were analyzed in both situations: Cast Iron, Stainless Steel AISI 202 and Steel Alloy. Following the comparative study for the three materials, it can be specified the importance of the material for the construction of the camshaft. Keywords: Camshaft, Static analysis, Autodesk Inventor

Study for Performance Increase of a Extractor Device by Steel Replacement of AISI 304 Steel for AISI 420 Steel.

The performance of an extractor device used in the food industry was studied from the development of structural analysis through computational modeling based on finite elements. These analyses considered the mechanical properties of AISI 304 and 420 stainless steels, in addition to the tribological aspects of the device in operation. Initially, uniaxial tensile tests were carried out according to the ABNT NBR 6892 standard and hardness tests were carried out according to ASTM E384, E92, and E18 standards. From the mechanical tests, structural analyses were carried out numerically on each of the components of the extractor device. After analyzing all the components, the device was assembled to be tested in operation. The wear and service life of devices made from these two materials were evaluated. From this study, it could be concluded that the extractor device made with AISI 420 stainless steel, in addition to having a lower manufacturing cost, suffered less wear and had an increase in service life of up to 650% compared to the extractor device made with steel stainless steel AISI 304.

Formability Prediction of Laser-Welded Stainless Steel AISI 304 and AISI 430

The effect of laser welding on the mechanical properties and the prediction of formability for austenitic stainless steel AISI 304 and ferritic steel AISI 430 when welded by a YLS-5000 fiber laser, were studied in the paper. The microstructure of the welded joint was analyzed using light microscopy. The mechanical properties were determined by static tensile testing. The forming limit diagrams were produced from notched samples at R5, R17, and R25 mm. The hardness values of the welded joint and the base material were determined using the Vickers method. Samples made of AISI 430 showed that the formability suffered due to laser welding. Longitudinal coarse ferrite grains were observed in the microstructure of the AISI 430 weld metal. The coarse-grained structure of the welded joint and the continuous interface along the centerline caused the failure of the AISI 430 laser-welded samples at significantly lower actual stress and strain values than were required to break the base material. No significant changes in the formability were observed in the AISI 304 samples after laser welding. The growth of dendrites was observed in the microstructure of the AISI 304 welded joint in a direction towards the centerline of the welded joint. A comparison of the experimentally determined FLD0 values and the values calculated from predictive equations showed that a better agreement was achieved for uniform elongation than for the strain hardening exponent. The manufacturability and economic efficiency of selected parts of an exhaust system by hydromechanical drawing were evaluated on the basis of the process capability index Cpk.

Local Shielding Gas Supply in Remote Laser Beam Welding

The use of shielding gases in laser beam welding is of particular interest for materials interacting with ambient oxygen, e.g., copper, titanium or high-alloy steels. These materials are often processed by remote laser beam welding where short welds (e.g., up to 40 mm seam length) are commonly used. Such setups prevent gas nozzles from being carried along on the optics due to the scanner application and a small area needs to be served locally with inert gas. The article provides systematic investigations into the interaction of laser beam processes and parameters of inert gas supply based on a modular flat jet nozzle. Based on the characterization of the developed nozzle by means of high-speed Schlieren imaging and constant temperature anemometry, investigations with heat conduction welding and deep penetration welding were performed. Bead-on-plate welds were carried out on stainless steel AISI 304 for this purpose using a disc laser and a remote welding system. Argon was used as shielding gas. The interaction between Reynolds number, geometrical parameters and welding/flow direction was considered. The findings were proved by transferring the results to a complex weld seam geometry (C-shape).

Wear and corrosion behavior of nano carbide dispersed AISI304 stainless steel by laser surface processing

In this study, dispersion of tungsten carbide on AISI 304 stainless steel substrate has been carried out by laser melting of the sand blasted substrate using a 5 kW continuous wave (CW) Nd:YAG laser (with the beam diameter of 3 mm) with an output power ranging from 1.5–2 kW, and scan speed varying from 12 to 16 mm s−1 and simultaneous feeding of premixed WC + Co powders in the ratio (wt) of 1:4 (with a flow rate of 10 mg s−1). The microstructure of the composite zone is dendritic or cellular in morphology and consists of nano-tungsten carbide (both WC and W2C) and M23C6 precipitates. There is an enhancement in hardness due to carbide dispersion from 220 VHN of the as-received substrate to 290–400 VHN. The wear resistance is improved significantly with a maximum enhancement observed in the sample processed with an applied power of 2 kW and a scan speed of 12 mm s−1. The corrosion rate in a 3.56 wt% NaCl solution is significantly reduced due to laser processing in most samples except when processed with 2.5 kW applied power and 12 mm s−1 scan speed. However, pitting corrosion resistance is found to be improved (shifting of Epit towards noble direction) for the sample processed with an applied power of 2 kW and a scan speed of 12 mm s−1.

Development of Rapidly-Quenched Al-Ge-Si Filler Alloys for the Joining of Stainless Steel AISI 304 and Aluminum Alloy AA6082

Aluminum alloys based on the Al-Ge-Si system with a germanium content of up to 40 wt.%, promising for the brazing of aluminum alloy AA6082 with the stainless steel AISI 304, were studied. The temperature characteristics and microstructural and mechanical properties of the filler alloys were systematically investigated. Differential scanning calorimetry showed that with an increase in the germanium content from 28.0 to 40.0 wt.%, the liquidus temperature of the filler alloys decreased from 514.8 to 474.3 °C. X-ray diffraction analysis and electron microscopy data showed that the foil of the filler alloys reveals a homogeneous structure. The ingots of the alloys contain two eutectics, the first of which consists of a solid solution of (Al, Ge) with a solid solution of (Ge, Si), and the second consists of a solid solution of (Al, Ge) with a solid solution based on (Ge). When the content of germanium increases from 28.0 to 40.0 wt.%, a separation of the faceted solid solution particles (Ge, Si) and an increase in their number could be observed. Nanohardness measurements showed that the (Ge, Si) and (Ge) solid solutions had similar nanohardness, with values of 11.6 and 10.2 GPa, respectively. Simultaneously, the Al solid solution and the intermetallic Al7Ge2Fe phase exhibited significantly lower nanohardness values of 0.7 and 6.7 GPa, respectively. Brinell hardness measurements showed that the ingots of the filler alloys were sufficiently ductile and had a hardness comparable to that of AA6082, which is used for brazing with AISI 304 stainless steel. The obtained results for the studied ingots and the rapidly quenched foils can be used to predict the forming structure of the seam after brazing and adjusted for diffusion processes occurring between the brazed materials and the studied filler alloys.

A review on machining performance of AISI 304 steel

Austenitic stainless steels (AISI 304) is most versatile grade in stainless steel and widely used in various industries owing to its attractive properties. It has high durability, high ductility, toughness at cryogenic temperature and excellent resistance against corrosion. In addition, this steel has excellent weldability, high resistance against fatigue and oxidation. However, owing to their high work hardening, high built up edge and low heat conductivity, AISI 304 stainless steel is considered as most difficult to-cut material than other alloy steels. To overcome this, various cutting fluids are used to enhance the life of cutting tools, reduce cutting temperature, reduce friction between tool and workpiece, and to improve the machining efficiency and surface integrity. Thus, the aim of this review paper is to summarize the various investigations done by distinct researchers on machining performance of AISI-304 stainless steel. In addition, various applications and factor that affect the performance of AISI-304 stainless steel are also discussed, so that this paper could become useful for the futuristic researchers to select optimum machining parameters, coolant type and machine for improving the overallmachined surface integrity.

Cyclic deformation behavior of metastable austenitic stainless steel AISI 347 in the VHCF regime at ambient temperature and 300 °C

Very high cycle fatigue (VHCF) tests on metastable austenitic stainless steels using an ultrasonic fatigue testing (USFT) system are challenging due to the transient material behavior and associated pronounced self-heating effects. Because the conventional measurement of stress-strain hysteresis is not possible in USFT, the cyclic deformation behavior can’t be described in a conventional manner. Hence, an energy-based approach is proposed for the characterization of cyclic deformation behavior of austenitic stainless steels in the VHCF regime at ambient temperature (AT) and elevated temperature. Therefore, in-situ dissipated energy and temperature measurements were performed. At AT both values underwent a change during cyclic loading, while at 300 °C only the dissipated energy changed. The investigated metastable austenitic stainless steel AISI 347 (X6CrNiNb1810, 1.4550) showed cyclic softening in the high cycle fatigue (HCF) regime (Nf < 107) at both testing temperatures, which led to specimen failure. In the VHCF regime, cyclic hardening was observed, which resulted in reaching the limiting number of load cycles Nl = 2 × 109 without specimen failure. This change in the cyclic deformation behavior by a small reduction of the stress amplitude led to a horizontal course of the Woehler curve in the VHCF regime and resulted in the true endurance limit for the investigated material. At AT, ferromagnetic α′-martensite was detected in all fatigued specimens using magnetic measurements. At 300 °C only specimens which reached the limiting number of cycles without failure exhibited a small amount of α′-martensite.

Wear Behaviors of Stainless Steel and Lubrication Effect on Transitions in Lubrication Regimes in Sliding Contact

The wear behavior of AISI304 stainless steel was investigated under dry, water-, and oil-lubricated conditions. A block-on-disk wear test was conducted in this work, since the test conditions could be controlled easily. For oil-lubricated contact, a significant amount of thin and elongated cutting chip-like debris was observed. This is attributed to the high lubricating effect of oil. Strain-induced martensitic (SIM) transformation was observed for all AISI304 blocks after the wear test, while AISI304 consisted of a single γ-austenite phase prior to the wear test. The Stribeck curve and the corresponding lubrication regimes were also considered to explain the wear behaviors and lubrication effect of AISI304. In comparison to the dry or water-lubricated conditions, which fall in the boundary lubrication regime at a low rotation speed, it is considered that the high viscosity of the oil-based lubricant causes the lubrication condition to enter the mixed lubrication regime early at a lower speed, thus reducing the specific wear rate over the 100–300 rpm range.

Influence of machining parameters on surface roughness in wire EDM using zinc coated brass wire

This study discussed the influence of cutting parameters such as (wire feed, wire tension, servo voltage, pulse on time, pulse off time) on surface roughness quality of stainless steel AISI 310 L material as a workpiece in the wire electrical discharge machining process and used Zinc coated brass wire. In order to obtain the best value for surface roughness. In this research four levels of factors affecting the process were used, the values of wire feed (4, 5, 6, and 7) m/min, wire tension (5, 6, 7, and 8) kgf, and servo voltage (20, 30, 40, and 50) Volt, and pulse on time (15, 20, 25, and 30) µsec, pulse off time (30, 40, 50, and 60) µsec. The results showed that the Taguchi method was implemented using the MINITAB 17 program. Experiments proved the best value of surface roughness is obtained was (1.56) µm at experimentally and (1.5461) µm at predictable program. The best values for surface roughness were by using zinc-coated copper wire when at wire feed (6) m/min , wire tension (6) kgf, servo voltage (50) volt, pulse on time (25) µsec, pulse off time (30) µsec. Surface roughness can be predicted using the coefficient determination (R-sq) (94.76 percent).

Microstructure, Anisotropy and Formability Evolution of an Annealed AISI 430 Stainless Steel Sheet

The effect of the microstructure on the principal strain paths (uniaxial, plane, and biaxial) in the formability processes of ferritic stainless steel AISI 430 sheets is studied. The Marciniak test (determination of the plastic strain of sheet metal with a flat tip punch) is applied to determine the forming limit curves and different strain levels in the strain paths by the digital image correlation technique. The formability is discussed in light of the microstructure, standard mechanical properties, work hardening behavior, and anisotropy measurements (R‐value). Electron backscatter diffraction analysis is carried out to determine the texture of the selected strain paths. The texture evolution shows a marked γ (&lt;111&gt;// normal direction [ND]) fiber and cube ({001} &lt;100&gt;) texture component under the biaxial strain mode, whereas the α (&lt;110&gt;// rolling direction [RD]) fiber is somewhat favored under uniaxial plane strain. The results are compared with texture simulations performed under the fully constrained Taylor model, finding reasonable agreement with the experimentally measured main components.

CRYOGENIC MILLING OF METASTABLE AUSTENITIC STAINLESS STEEL AISI 347

The metastable austenitic stainless steel AISI 347 offers the possibility to induce a phase transformation from γ-austenite to ε- and α’-martensite when machining. This knowledge is well understood during cryogenic turning and was already applied to improve the surface morphology of metastable austenitic steel. However, the potential of this in-process hardening method is so far limited to rotationally symmetrical components. The aim of this study is to investigate deformation induced phase transformation during cryogenic milling, aiming at an improved surface morphology and at the resulting beneficial surface properties of the workpiece for parts with complex geometries.

Mechanical and Metallurgical Characterisation of CO2 Laser Beam Welding AISI 4130 and AISI 310 Sheets of Steel

Abstract Laser Beam Welding (LBW) is the fusion welding technique in which coalescence is produced by heating the work piece by impingement of concentrated beam of laser light. In this paper a full depth butt welding of alloy steel AISI 4130 and stainless steel AISI 310 of 2 mm thickness by using CO2 Laser Beam Welding machine has been performed. Design of experiment is done by using Taguchi method L25 i.e. level 5 by considering process parameters i.e. power, welding speed, beam angle, focal point position and focal length. The experimental output results that are measured for the mechanical properties of welds (Ultimate Tensile Strength and Hardness). The analysis was carried out to explain the influence of the LBW processing parameters values on the mechanical and microstructural aspects. The weld Joint is analysed by Optical Microstructure and Scanning Electron Microscopy (SEM). The Energy Dispersive X-Ray Analysis (EDAX) was carried out to determinate the chemical composition of the weld zone.

Gas-discharge plasma application for ion-beam treatment of the holes’ inner surfaces

The possibility to modify the holes and pipes’ inner surface with focused high-intensity low-energy ion beams was first shown in this work. The studies were carried out using an axially symmetric single-grid system for the ions’ extraction from a free plasma boundary with subsequent ballistic focusing of the ion beam. Ion implantation of the inner surface was carried out in the region of the ion beam defocusing. The studies considered the effect of a nitrogen ions’ beam with energy of 1.4 keV on the inner surface of a tube with a diameter of 20 mm made of stainless steel AISI 321. The beams were formed with a repetition rate of 40 kHz and pulse durations of 5, 7.5 and 10 μs. It is shown that the mutual deposition of the sputtered material on the tube’ opposite sides partly compensates for ion sputtering. As a result of implantation of the inner surface of a pipe made of stainless steel AISI 321, the nitride layers with a thickness of more than 15 microns with a nitrogen dopant content of 22-30 at.% were obtained.

An In-Situ Electrochemical Nanoindentation (ECNI) Study on the Effect of Hydrogen on the Mechanical Properties of 316L Austenitic Stainless Steel.

In-situ electrochemical nanoindentation (ECNI) has been used to study the effect of hydrogen on the mechanical properties of austenitic stainless steel AISI 316L. Changing the electrode potential (via electrochemical charging) revealed the interconnected nature of the hydrogen effect on the nanomechanical properties of the stainless steel. At more positive cathodic potentials, a softening effect of hydrogen can be noticed, while significant hardening can be observed at more negative cathodic potentials. The hydrogen effects on the nanomechanical properties were analyzed in terms of the homogeneous dislocation nucleation (HDN) and the hydrogen-dislocation interactions from the energy point of view. The effects can be explained with the framework of the defactant theory and the hydrogen-enhanced localized plasticity (HELP) mechanism.

A Comparison of Different Natural Groundwaters from Repository Sites—Corrosivity, Chemistry and Microbial Community

In Finland, the repositories for low and intermediate-level radioactive waste (LLW and ILW) will be situated at three different geographical locations in about 60 to 100 m deep granite bedrock where the waste and waste containers can be subjected to anoxic groundwater containing microbes. The composition of groundwater varies in terms of chemistry and microbial activity in different locations. In this study, groundwater from the three repository areas was analyzed in respect to chemistry and microbial community. Corrosion tendency of three steel grades, carbon steel AISI/SAE 1005 and stainless steels AISI 304 and 316L, was studied in these groundwater environments using electrochemical methods. As a reference, measurements were also performed in simulated groundwater without microbes. The measurements show that corrosivity of the water and thus the steels’ performance differs depending on water origin. In addition, the groundwater differed remarkably in their chemical composition as well as abundance and diversity of microbial community between the sites. Consequently, the local environment has to be considered when evaluating the long-term evolution of disposal concepts.

Comparative Research of Microstructure and Mechanical Properties of Stainless and Structural Steel Dissimilar Welds.

The present study utilized a metal inert gas welding (MIG) to make a dissimilar weld of stainless steel AISI 304, 314, 316L, 420 grades and a standard structural steel S355MC. It refers to a weld joining two materials from different alloy systems commonly used in heat exchangers, pressure vessels, and power plant systems. Obviously, maintaining the integrity of such welds is of paramount importance to the safety issues. Therefore, detailed microscopic and experimental studies were performed to evaluate the reliability of these welds. The microscopic analysis did not reveal any presence of weld defects such as porosity or cracks, which ensured that MIG process parameters were properly selected. The performance of dissimilar welds was assessed by hardness and tensile tests. The hardness profiles revealed differences between austenitic and martensitic steel welds that later showed extremely high values in the heat-affected zone (HAZ), which caused fractures in this zone during tensile test. The welds of all austenitic steel grades withstood the tensile test, showing an average tensile strength of 472 MPa with fractures observed in the base metal zone. It made clear that the use of a filler rod 308LSI is suitable only for the austenitic stainless and structural steel dissimilar welds and not appropriate for martensitic-structural steel welds. The achieved results revealed that the higher hardness of the martensitic phase in the HAZ of AISI 420 is closely related with the formation of untempered coarse martensitic structure and higher carbon content.

Modelling and simulation of densification and σ-phase precipitation in PM duplex steel AISI 318LN during hot isostatic pressing

Following the development of hot isostatic pressing (HIP) with integrated rapid cooling technology, it is now possible to combine consolidation of encapsulated powder and subsequent heat treatment in a single process step in a pressure vessel. Using this technology, a near-net-shape product with target microstructure can be achieved. However, qualified final products still require traditional expensive and time-consuming trial-and-error tests. To eliminate these costly trial-and-error tests and achieve the required final properties of the products, it is urged to develop a combined numerical model to precisely predict the geometrical changes of the component during the HIP process and the evolution of significant microstructural features. This is realised in this work exemplarily by using duplex stainless steel AISI 318LN. This steel was selected due to requirements coming from applications regarding precise complex shaped near-net-shape components combined with high strength and toughness by avoiding brittle σ-phase precipitation. In this study, an existing finite element model for the densification in the HIP process was supplemented by a model for σ-phase precipitation kinetics based on microscopical characterisation. Moreover, the temperature dependent heat transfer coefficient (HTC) was implemented in the developed model to simulate the evolution and the distribution of the σ-phase during cooling. The numerically simulated final component dimensions and σ-phase volume fractions were verified by comparing with experimental data obtained from specimens and components of various shapes produced by both conventional HIP process and HIP with integrated rapid cooling. The high consistency between experimental and numerical results validates the accuracy of the developed simulation approach.

Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering

AbstractZirconium nitride films are deposited onto stainless steel AISI 316L and silicon (100) by radio frequency magnetron sputtering at different nitrogen flow ratios [N2/(Ar+N2)] varied between 0 and 0.25). Scanning electron microscope, atomic force microscopy, X‐ray diffraction (XRD), and Raman are used to investigate the surface morphology and microstructure of the thin films. The mechanical and electrochemical properties of all coatings are evaluated and compared with the uncoated AISI 316L to explore the efficiency of surface modification. The XRD and Raman analysis show that all the films are crystalline. This shows that the increased nitrogen content leads to a transformation from hexagonal α‐Zr phase to cubic c‐Zr and then to mixed α‐Zr and face centered cubic c‐ZrN phases. The films deposited with nitrogen flow ratio of 0.2 show the highest hardness of 32.2 GPa. Using the potentiodynamic polarization method, the corrosion behavior of the films is studied in Hank's solution. The comparison between uncoated and coated substrates shows a decrease in corrosion current density for all coated samples.