Study of the Metallurgy of a Dissimilar Ti-6Al-4V – Stainless Steel Linear Fiction Welded Joints

2015 ◽  
Vol 651-653 ◽  
pp. 1427-1432 ◽  
Author(s):  
Filomena Impero ◽  
Fabio Scherillo ◽  
Antonello Astarita ◽  
Kathryn A. Beamish ◽  
Michele Curioni ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Intermetallic Compounds ◽  
Weld Line ◽  
Beta Phase ◽  
Alpha Phase ◽  
Parent Material ◽  
Grain Structure ◽  
Linear Friction ◽  
Aisi 316 ◽  
Welding Processes

This paper deals with the investigation of the metallurgy of a dissimilar Ti-6Al-4V-stainless steel joint linear friction welded. In particular two different stainless steel were considered: AISI 304 and AISI 316. These two alloys differs in the Molybdemun content. Metallographic observations, EDS analysis and Vickers Microhardness measurements were carried out, particular attention was focused on the study of the intermetallic compounds and on the microstructures of the different zones produced by the process. As usual for solid state welding processes, three different zones can be identified: the parent material, the heat affected zone (HAZ) and the thermo-mechanical affected zone (TMAZ), furthermore a very thin joining line, rich of intermetallic compounds, was also observed. In this zone diffusive phenomena also occurred resulting in a variation of the alpha phase content on the titanium side.In the TMAZ, the bimodal microstructure of the parent material was deformed and the presence of elongated alpha grains with broken beta-phase particles was established. Moreover it was observed that in the weld region, exposure to supertransus temperatures (995°C) combined with hot-deformation working and rapid cooling after joining induced the recrystallization of a martensitic beta grain structure. Concerning the joint between Ti-6Al-4V and AISI 316 some cracks were observed within the weld line, this due to the presence of brittle intermetallics compounds in this zone. The formation of these intermetallics was promoted by the presence of Molybdenum.

Characterisation of Long Term Aging in Esshete 1250 Welds

2018 ◽  
Vol 941 ◽  
pp. 589-594
Author(s):  
Oscar Stephenson ◽  
Rebecca L. Higginson ◽  
Simon Hogg ◽  
Jacob Knight ◽  
Sarah Spindler
Keyword(s):  
Stainless Steel ◽  
Sigma Phase ◽  
Parent Material ◽  
Grain Structure ◽  
Grain Structures ◽  
Two Samples

In this work, two samples of service grade Esshete 1250 stainless steel, as-received and aged, were characterised to determine the microstructural differences between the parent material and weld in terms of the grain structures and the phases present using XRD, EBSD, SEM and EDS. There was no difference found in the grain structure, but the phases present in the aged weld showed that sigma phase developed during aging.

Friction Welding of Type 304 Stainless Steel to CP Titanium Using Nickel Interlayer

2013 ◽  
Vol 794 ◽  
pp. 351-357 ◽  
Author(s):  
C.H. Muralimohan ◽  
V. Muthupandi
Keyword(s):  
Stainless Steel ◽  
Intermetallic Compounds ◽  
Friction Welding ◽  
High Reliability ◽  
Pure Titanium ◽  
Nuclear Industry ◽  
Fusion Welding ◽  
304 Stainless Steel ◽  
Tensile Fracture ◽  
Welding Processes

Dissimilar metal joints of stainless steel to titanium find extensive industrial applications especially in the nuclear industry. However, it is well known that fusion welding of stainless steel to titanium is difficult because of the formation of brittle intermetallic compounds and the associated problems. To avoid this, welding processes or techniques with high reliability and productivity for these dissimilar materials are demanded. In the present work, joints comprising of 304 stainless steel and commercially pure titanium were produced by friction welding using nickel as interlayer. Investigation on the mechanical properties of the joints shows the occurrence of highest hardness value at the interface of titanium and nickel interlayer. X-ray diffraction studies confirmed the presence of various types of intermetallic compounds at the interface of the welded joint. The tensile strength of the joint varies with the thickness of nickel interlayer used. Joints having maximum strength equals to 72% of that of titanium base metal could be produced. In all the joints, tensile failure occurred at Ti-Ni interface due to the presence of the intermetallic compounds at this interface. Fracture surface analysis reveals that the tensile fracture path is along the intermixing zone of titanium and nickel interlayer.

Numerical Modeling of Grain Growth in Laser Engineered Net Shaping (LENS) of AISI 316 Stainless Steel

2017 ◽  
Author(s):  
Wenda Tan ◽  
Xuxiao Li
Keyword(s):  
Stainless Steel ◽  
Grain Growth ◽  
Molten Pool ◽  
Grain Structure ◽  
Scale Model ◽  
Modeling Framework ◽  
Laser Engineered Net Shaping ◽  
Macro Scale ◽  
Aisi 316 ◽  
Net Shaping

A multi-scale modeling framework is developed in this work to simulate the transport phenomena and grain growth in Laser Engineered Net Shaping (LENS) process of austenitic stainless steel AISI 316. A three-dimensional (3D) model is included to simulate the transient molten pool geometry and heat/mass transfer on a macro-scale; and a 3D meso-scale model based on the Cellular Automata method is included to predict the grain growth during molten pool solidification. The predicted grain structure is found to be consistent with the experimental results and reveals that the grain structure is highly dependent on the molten pool geometry.

scholarly journals Activated flux TIG welding of stainless steel pipes

2019 ◽  
Vol 25 (4) ◽  
pp. 353-360 ◽  
Author(s):  
M. Dramicanin ◽  
S. Balos ◽  
P. Janjatovic ◽  
I. Zabunov ◽  
V. Grabulov
Keyword(s):  
Stainless Steel ◽  
Weld Line ◽  
Oxide Particle ◽  
Material Behavior ◽  
Welding Parameters ◽  
Bending Properties ◽  
Steel Pipes ◽  
Orbital Welding ◽  
Activated Flux ◽  
Welding Processes

In this work, the presence of TiO2 nanoparticle-based activated flux combined with orbital welding of seamless thick-walled pipes of stainless steel and lowcycle pulse current was done, representing a novel combination of welding processes parameters. Control specimens were welded without flux and consumable material, and without flux with the consumable material. Experimental welding with different welding parameters was done. Special attention was given to characterize the flux by zetasizer method, representing a new approach, versus the conventional approach where the nominal oxide particle size is reported. The obtained welds were visually tested, macroanalyzed, their microstructures examined, and their tensile and bending properties determined. The results show that the flux influences a significant increase in penetration depth, up to full penetration, which has a positive effect on the increase in the tensile and bending properties of the weld metal. Material behavior model was developed, based on microstructural features of the near weld-line. Without the flux, grain enlargement occurred near the surface, while with flux, it occurred under the weld, which can be attributed to recrystallization and a reversed Marangoni convection.

Experimental and Numerical Investigation into Residual Stress During Turning Operation for Stainless Steel AISI 316

2020 ◽  
Vol 38 (12A) ◽  
pp. 1862-1870
Author(s):  
Safa M. Lafta ◽  
Maan A. Tawfiq
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Percentage Error ◽  
Depth Of Cut ◽  
Main Role ◽  
Turning Operation ◽  
Aisi 316

RS (residual stresses) represent the main role in the performance of structures and machined parts. The main objective of this paper is to investigate the effect of feed rate with constant cutting speed and depth of cut on residual stresses in orthogonal cutting, using Tungsten carbide cutting tools when machining AISI 316 in turning operation. AISI 316 stainless steel was selected in experiments since it is used in many important industries such as chemical, petrochemical industries, power generation, electrical engineering, food and beverage industry. Four feed rates were selected (0.228, 0.16, 0.08 and 0.065) mm/rev when cutting speed is constant 71 mm/min and depth of cutting 2 mm. The experimental results of residual stresses were (-15.75, 12.84, 64.9, 37.74) MPa and the numerical results of residual stresses were (-15, 12, 59, and 37) MPa. The best value of residual stresses is (-15.75 and -15) MPa when it is in a compressive way. The results showed that the percentage error between numerical by using (ABAQUS/ CAE ver. 2017) and experimental work measured by X-ray diffraction is range (2-15) %.

scholarly journals Structural Factors Inducing Cracking of Brass Fittings

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3255
Author(s):  
Lenka Kunčická ◽  
Michal Jambor ◽  
Adam Weiser ◽  
Jiří Dvořák
Keyword(s):  
Chemical Composition ◽  
Plastic Flow ◽  
Beta Phase ◽  
Alpha Phase ◽  
Structural Factors ◽  
Transmission Electron ◽  
Medical Gas ◽  
Hot Die Forging ◽  
Multiple Step

Cu–Zn–Pb brasses are popular materials, from which numerous industrially and commercially used components are fabricated. These alloys are typically subjected to multiple-step processing—involving casting, extrusion, hot forming, and machining—which can introduce various defects to the final product. The present study focuses on the detailed characterization of the structure of a brass fitting—i.e., a pre-shaped medical gas valve, produced by hot die forging—and attempts to assess the factors beyond local cracking occurring during processing. The analyses involved characterization of plastic flow via optical microscopy, and investigations of the phenomena in the vicinity of the crack, for which we used scanning and transmission electron microscopy. Numerical simulation was implemented not only to characterize the plastic flow more in detail, but primarily to investigate the probability of the occurrence of cracking based on the presence of stress. Last, but not least, microhardness in specific locations of the fitting were examined. The results reveal that the cracking occurring in the location with the highest probability of the occurrence of defects was most likely induced by differences in the chemical composition; the location the crack in which developed exhibited local changes not only in chemical composition—which manifested as the presence of brittle precipitates—but also in beta phase depletion. Moreover, as a result of the presence of oxidic precipitates and the hard and brittle alpha phase, the vicinity of the crack exhibited an increase in microhardness, which contributed to local brittleness.

Effects of Insert Nose Radius and Processing Cutting Parameter on the Surface Roughness of Aisi 316 Stainless Steel

2010 ◽  
Vol 447-448 ◽  
pp. 51-54
Author(s):  
Mohd Fazuri Abdullah ◽  
Muhammad Ilman Hakimi Chua Abdullah ◽  
Abu Bakar Sulong ◽  
Jaharah A. Ghani
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Finish ◽  
Feed Rate ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Depth Of Cut ◽  
Nose Radius ◽  
Aisi 316

The effects of different cutting parameters, insert nose radius, cutting speed and feed rates on the surface quality of the stainless steel to be use in medical application. Stainless steel AISI 316 had been machined with three different nose radiuses (0.4 mm 0.8 mm, and 1.2mm), three different cutting speeds (100, 130, 170 m/min) and feed rates (0.1, 0.125, 0.16 mm/rev) while depth of cut keep constant at (0.4 mm). It is seen that the insert nose radius, feed rates, and cutting speed have different effect on the surface roughness. The minimum average surface roughness (0.225µm) has been measured using the nose radius insert (1.2 mm) at lowest feed rate (0.1 mm/rev). The highest surface roughness (1.838µm) has been measured with nose radius insert (0.4 mm) at highest feed rate (0.16 mm/rev). The analysis of ANOVA showed the cutting speed is not dominant in processing for the fine surface finish compared with feed rate and nose radius. Conclusion, surface roughness is decreasing with decreasing of the feed rate. High nose radius produce better surface finish than small nose radius because of the maximum uncut chip thickness decreases with increase of nose radius.

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