Austenitic SS304 Research Articles

Optimization of cylindrical grinding process parameters on austenitic stainless steel 304 using Taguchi based Grey Relational Analysis

A cylindrical grinding machine is used to grind and form an object's exterior and is generally used in finishing process. Though near-net shape technology is evolving, finishing processes are frequently required to achieve dimensional accuracy and a satisfactory surface quality. Cylindrical grinding machine can operate with different types of shapes, provided the workpiece should have a rotating axis at center. In this study, austenitic SS304 was selected as the material of workpiece. It is used for domestic as well as industrial applications. This research focuses on applying Taguchi technique and Grey Relational Analysis for selecting optimal cylindrical grinding process variables for austenitic stainless steel 304. The process parameters in grinding operation serve as the input factors, the combination of which greatly affects the output responses. The grinding process variables investigated in this research work are workpiece speed, longitudinal feed, transverse feed and flow rate of the coolant. The effect of these grinding factors is analyzed on the performance measures: surface roughness and material removal rate. The experimentation was done based on L9 orthogonal array generated using the Taguchi technique. Further, optimal grinding process parameters (work speed = 20 m/min, longitudinal feed = 6 m/min, transverse feed = 0.02 mm, coolant flow rate = 1.43 l/min) which satisfy both the responses (surface roughness = 0.395 µm and Material Removal Rate = 189.37 mm3/s) were predicted using Grey Relational Analysis.

An assessment for mechanical and microstructure behavior of dissimilar material welded joint between nuclear grade martensitic P91 and austenitic SS304 L steel

The microstructural evolution and mechanical properties of gas tungsten arc welded creep strength enhanced martensitic (CSEM) and austenitic stainless steel (SS) dissimilar welded joint is explored in the as welded (AW) and post weld heat treated (PWHT) conditions. The as received normalized and tempered P91 steel has been welded with SS304 L by preparing a conventional groove and employing a P91 GTAW filler wire. The welded plate is subjected to PWHT at 760 °C for 120 min followed by air cooling. The P91 steel in as received condition exhibited fully martensitic (tempered) structure with lathe morphology and prior austenite grain boundaries while SS304 L have austenitic structure with twins. The heterogeneity (as-welded condition) across the welded joint were produced in terms of microstructure and mechanical properties (hardness, Charpy toughness and tensile strength). The variation in mechanical properties has been minimized after the PWHT. PWHT has observed a drastic influence on mechanical properties and microstructure of weld fusion zone and HAZ of P91 side however, remain unaffected for the SS304 L side HAZ. The strength of the welded joint have been measured 1016 ± 2.5 MPa and 906 ± 6.5 in as-welded and PWHT condition with joint efficiency of 140 % and 125 %, respectively.

High-pressure torsion assisted segregation and precipitation in a Fe-18Cr-8Ni austenitic stainless steel

During irradiation or high-temperature aging, stainless steel can develop precipitates, significantly affecting mechanical properties. In this study atom probe tomography (APT) was used to study grain boundary segregation and secondary phases in a purely austenitic SS304 (a Fe-18Cr-8Ni steel) processed by high-pressure torsion (HPT) at 300 °C. Ni, Mn, Si enriched phase was observed at grain boundaries, and Cu nanoprecipitates were observed along and near phase/grain boundaries. Precipitation is facilitated by deformation assisted segregation along grain boundaries with a mechanism similar to vacancy diffusion in irradiated steels.

Multiwavelength Raman Spectroscopic Analysis of Superficial Iron-Chromium Oxides Generated Using Laser Irradiation.

In order to characterize iron-chromium oxides generated by laser irradiation on the surface of stainless steel plates, an ultraviolet-visible (UV-Vis) near-infrared (NIR) multiwavelength excitation Raman analysis has been performed using both austenitic SS304 and ferritic SS430 stainless steel samples. Raman spectra were obtained using five different excitation wavelengths from blue (455 nm) to NIR (830 nm). These measurements have allowed us to observe and identify four Raman bands, among which two have not been previously observed for iron-chromium oxides, and characterize the existence of different resonant excitation conditions for the different excitation wavelengths. For example, when using 455 nm as excitation wavelength the band at 485 cm-1 did not show up, although that when using 830 nm as excitation wavelength is a clear characteristic band for iron-chromium oxide. In addition, the dependence of the spectra profile with the excitation wavelength for films and microspheres features was observed. This experimental Raman analysis shows the importance of the excitation wavelength for the characterization of metallic oxides with different features.

Microstructural investigation of Ni based cladding developed on austenitic SS-304 through microwave irradiation

The stainless steel SS-304 is used to produce turbine blades in some of the hydraulic power plants. It has excellent corrosion resistance and forming characteristics. In the present investigation, the nickel based clads were developed through microwave energy using domestic microwave oven equipped with 900W power at 2.45GHz frequency. The developed clads were characterized through optical metallography, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and porosity. Microstructure study revealed that microwave clads are free from visible interfacial cracks and porosity is significantly less at approximately 0.87%. The various complex metal carbides and intermetallics were found through XRD analysis. The distribution of metal carbides and intermetallics are the clearest indication for the improvement of hardness. The average microhardness of the developed clad surface is 364±70HV.

Optimization of Process Parameters for Resistance Spot Welding process using Taguchi Method for Austenitic SS304

Optimization of Process Parameters for Resistance Spot Welding process using Taguchi Method for Austenitic SS304