Laser Welding of AISI 316 Steel: Microstructural and Stress Analysis

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
B. S. Yilbas ◽  
Sohail Akhtar
Keyword(s):  
Residual Stress ◽  
Base Material ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cooling Period ◽  
Thermal Stress Field ◽  
Electron Microscopes ◽  
Aisi 316 ◽  
Scanning Electron Microscopes

Thermal-stress field in the welded region was modeled incorporating the finite element model. Temperature and stress fields were predicted at different cooling periods. The morphological and metallurgical changes in the welded region were examined using optical and scanning electron microscopes, energy dispersive spectroscopy and X-ray diffraction. The residual stress formed at the surface vicinity of the weld was determined using the X-ray diffraction technique. It was found that the residual stress predicted agreed well with the experimental data. The solidification cracking did not occur in the weld section during the cooling period. The microhardness in the weld cross-section was almost 1.4 times the base material hardness.

Simulation and Experiment on the Residual Stress in Super-High Speed Grinding

2010 ◽  
Vol 135 ◽  
pp. 238-242
Author(s):  
Yue Ming Liu ◽  
Ya Dong Gong ◽  
Wei Ding ◽  
Ting Chao Han
Keyword(s):  
Residual Stress ◽  
High Speed ◽  
Element Model ◽  
Residual Stress Distribution ◽  
X Ray Diffraction ◽  
Machined Surface ◽  
X Ray ◽  
High Speed Grinding ◽  
Simulation And Experiment ◽  
Cylindrical Workpiece

In this paper, effective finite element model have been developed to simulation the plastic deformation cutting in the process for a single particle via the software of ABAQUS, observing the residual stress distribution in the machined surface, the experiment of grinding cylindrical workpiece has been brought in the test of super-high speed grinding, researching the residual stress under the machined surface by the method of X-ray diffraction, which can explore the different stresses from different super-high speed in actual, and help to analyze the means of reducing the residual stresses in theory.

Analysis on Microstructure of Laser Brazing Diamond Grits with a Ni-Based Filler Alloy

2010 ◽  
Vol 97-101 ◽  
pp. 3879-3883 ◽  
Author(s):  
Zhi Bo Yang ◽  
Jiu Hua Xu ◽  
Ai Ju Liu
Keyword(s):  
Active Element ◽  
Steel Substrate ◽  
Parameters Optimization ◽  
Interfacial Region ◽  
Filler Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cross Diffusion ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

Brazing diamond grits onto steel substrate using a Ni-based filler alloy was carried out via laser beam in an argon atmosphere. The microstructure of the interfacial region among the Diamond grits and the filler layer were investigated by means of scanning electron microscopes (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Meanwhile, the formation mechanism of carbide layers was discussed. All the results indicated that the active element chromium in the Ni-based alloy concentrated preferentially to the surface of the grits to form a chromium-rich layer, and the hard joint between the alloy and the steel substrate is established through a cross-diffusion of iron and Ni-based alloy through parameters optimization.

Otosclerotic Stapes: Morphological and Microchemical Correlates

1977 ◽  
Vol 86 (4) ◽  
pp. 525-540 ◽  
Author(s):  
David J. Lim ◽  
William H. Saunders
Keyword(s):  
Calcium Salt ◽  
Mineral Deposit ◽  
Ground Substance ◽  
X Ray Diffraction ◽  
Typical Pattern ◽  
X Ray ◽  
Initial Stage ◽  
Electron Microscopes ◽  
Sclerotic Lesions ◽  
Scanning Electron Microscopes

A total of 32 otosclerotic stapes is thin-sectioned without decalcification and examined using transmission and scanning electron microscopes, with a nondispersive x-ray analyzer attached to the latter. These otosclerotic stapes are classified as spongiotic, sclerotic, or preotosclerotic, according to their pathologic characteristics and state of mineralization. Either diffuse or patchy demineralization in the ground substance appears to be the initial stage of otosclerosis, and this area coincides with preotosclerotic lesions (also known as blue mantle) in light microscopy. Therefore, it is interpreted that demineralization precedes the destruction of ground substance in the preotosclerotic lesion. Bone mineral deposits in new otosclerotic bone appear to be related to the collagen fibrils that are embedded in the ground substance. No mineral deposit could be seen without the ground substance deposition; therefore, it is suggested that this ground substance is the single most important factor in the poor mineralization of the otosclerosis. The sclerotic lesions are well mineralized and show a typical pattern of hydroxyapatite by x-ray diffraction study. We could not confirm the notion that the sclerotic lesion is hypermineralized as compared to the normal stapes. The spongiotic lesions are poorly mineralized, with low calcium salt. Using the Ca/P ratio and x-ray diffraction pattern as criteria, it was determined that spongiotic lesions belong to unstable, immature bone.

Residual Stresses in Butt Welding of Two Circular Pipes: An Experimental and Numerical Investigation

2014 ◽  
Author(s):  
Gurinder Singh Brar
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Welding Process ◽  
Diffraction Method ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray

Welding is a reliable and efficient joining process in which the coalescence of metals is achieved by fusion. Welding is carried out with a very complex thermal cycle which results in irreversible elastic-plastic deformation and residual stresses in and around fusion zone and heat affected zone (HAZ). A residual stress due to welding arises from the differential heating of the plates due to the weld heat source. Residual stresses may be an advantage or disadvantage in structural components depending on their nature and magnitude. The beneficial effect of these compressive stresses have been widely used in industry as these are believed to increase fatigue strength of the component and reduce stress corrosion cracking and brittle fracture. But due to the presence of residual stresses in and around the weld zone the strength and life of the component is also reduced. To understand the behavior of residual stresses, two 10 mm thick Fe410WC mild steel plates are butt welded using the Metal Active Gas (MAG) process. An experimental method (X-ray diffraction) and numerical analysis (finite element analysis) were then carried out to calculate the residual stress values in the welded plates. Three types of V-butt weld joint — two-pass, three-pass and four-pass were considered in this study. In multi-pass welding operation the residual stress pattern developed in the material changes with each weld pass. In X-ray diffraction method, the residual stresses were derived from the elastic strain measurements using a Young’s modulus value of 210 GPa and Poisson’s ratio of 0.3. Finite element method based, SolidWorks software was used to develop coupled thermal-mechanical three dimension finite element model. The finite element model was evaluated for the transient temperatures and residual stresses during welding. Also variations of the physical and mechanical properties of material with the temperature were taken into account. The numerical results for peak transverse residual stresses attained in the welded plates for two-pass, three-pass and four-pass welded joint were 67.7 N/mm2, 58.6 N/mm2, and 48.1 N/mm2 respectively. The peak temperature attained during welding process comes out to be 970°C for two-pass weld, 820.8°C for three-pass weld and 651.9°C for four-pass weld. It can be concluded that due to increase in the number of passes during welding process or deposition weld beads, the residual stresses and temperature distribution decrease. Also, the results obtained by finite element method agree well with those from experimental X-ray diffraction method.

Residual Stress Measurements in Multi-Pass Welded High Strength Steel Using Energy Dispersive Synchrotron X-Ray Diffraction

2014 ◽  
Vol 922 ◽  
pp. 177-182
Author(s):  
H. Gao ◽  
R.M. Huizenga ◽  
R.K. Dutta ◽  
M. Amirthalingam ◽  
M.J.M. Hermans ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Strength ◽  
Depth Resolution ◽  
Element Model ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Tensile Stresses ◽  
Transverse Tensile

Six pass welds were made on a 16 mm thick high strength quenched and tempered structural steel plate (S690QL1, Fe-0.16C-0.2Si-0.87Mn-0.33Cr-0.21Mo (wt.%)). Depth resolved measurements in two orthogonal directions were carried out using energy dispersive synchrotron X-ray diffraction at the ID15 beamline of the European Synchrotron Radiation Facility. The strains were calculated from the shift in the local d-spacing for four bcc planes ({200}, {211}, {220}, {310}). The planar stresses were calculated from the biaxial Hooke’s law, using the diffraction elastic constants of the individual planes. A two dimensional cross-sectional residual stress map with a depth resolution of 2 mm was obtained. Transverse compressive stresses were found at the weld toes and root. Transverse tensile stresses were present in the middle of the plate. Longitudinal tensile stresses concentrated along the fusion line. This work describes the procedures to obtain the depth resolved residual stress map and the generated results provide necessary information to validate thermal mechanical finite element model of multi-pass welding.

Effect of Boriding Time on Microstructure and Residual Stresses in Borided Highly Alloyed X210CR12 Steel

2014 ◽  
Vol 606 ◽  
pp. 27-30 ◽  
Author(s):  
Zdenek Pala ◽  
Radek Mušálek ◽  
Jiří Kyncl ◽  
Petr Harcuba ◽  
Josef Stráský ◽  
...  
Keyword(s):  
Residual Stress ◽  
Wear Resistance ◽  
Residual Stresses ◽  
Surface Hardness ◽  
Base Material ◽  
Chemical Polishing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Borided Layer ◽  
Depth Distributions

Boriding of highly alloyed steels done with the aim of increasing their wear resistance faces several issues connected with the microstructure of the base material and restraints during the diffusion of boron. The aim of the performed analyses was to ascertain whether significant increase of boriding time can enhance the surface hardness, contribute to creation of more compact microstructure and even lead to beneficial state of residual stresses in the borided layer. Using combination of X-ray diffraction and electro-chemical polishing, residual stress depth distributions in few tens of micrometres thick borided layers were obtained.

scholarly journals Preparation and properties of nanocrystalline Ni/graphene composite coatings deposited by electrochemical method

2018 ◽  
Vol 20 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Grzegorz Cieślak ◽  
Maria Trzaska
Keyword(s):  
Steel Substrate ◽  
Composite Coatings ◽  
X Ray Diffraction ◽  
Dispersion Phase ◽  
X Ray ◽  
Graphene Layers ◽  
Nano Crystalline ◽  
Graphene Flakes ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

Abstract The paper presents results of studies of composite nickel/graphene coatings produced by electrodeposition method on a steel substrate. The method of producing composite coatings with nanocrystalline nickel matrix and dispersion phase in the form of graphene is presented. For comparative purposes, the study also includes nano-crystalline Ni coatings produced by electrochemical reduction without built-in graphene flakes. Graphene was characterized by Raman spectroscopy, transmission and scanning electron microscopes. Results of studies on the structure and morphology of Ni and Ni/graphene layers produced in a bath containing different amounts of graphene are presented. Material of the coatings was characterized by SEM, light microscopy, X-ray diffraction. The microhardness of the coatings was examined by Knoop measurements. The adhesion of the coatings with the substrate was tested using a scratchtester. The influence of graphene on the structure and properties of composite coatings deposited from a bath with different graphene contents was determined.

Failure Analysis of the Pressure Vessel by Stainless Steel: 1Cr18Ni9Ti

2004 ◽  
Vol 126 (4) ◽  
pp. 414-418 ◽  
Author(s):  
Junbo Zhou ◽  
Kuisheng Wang ◽  
Liping Gao
Keyword(s):  
Stainless Steel ◽  
Pressure Vessel ◽  
Electrochemical Corrosion ◽  
Chloride Ions ◽  
X Ray Diffraction ◽  
Corrosion Failure ◽  
X Ray ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Welding Position

The corrosion failure of 1Cr18Ni9Ti stainless steel pressure vessel was studied with the aid of metallurgical microscopes, scanning electron microscopes, scanning Auger energy spectra and X-ray diffraction meters. The main causes of the failure included: inter-crystalline corrosion initiated at or near welding position between head and body of cylinder, electrochemical corrosion due to chloride ions in electrolyte and corrosive action formed by oxygen separator and hydrogen separator. Some measures of corrosion resistance and design improvement were proposed.

Laser Brazing of Diamond Grits with a Ni-Based Brazing Alloy

2007 ◽  
Vol 359-360 ◽  
pp. 43-47 ◽  
Author(s):  
Zhi Bo Yang ◽  
Jiu Hua Xu ◽  
Yu Can Fu ◽  
Hong Jun Xu
Keyword(s):  
Active Element ◽  
Steel Substrate ◽  
Interfacial Region ◽  
X Ray Diffraction ◽  
Laser Brazing ◽  
X Ray ◽  
Cross Diffusion ◽  
Filler Layer ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

Brazing diamond grits onto steel substrate using a Ni-based filler alloy was carried out by laser beam in an argon atmosphere. The microstructure of the interfacial region among the Diamond grits, the filler layer and the steel substrate, were investigated by means of scanning electron microscopes (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Meanwhile, the formation mechanism of carbide layers was discussed. All the results indicated that the active element chromium in the Ni-based alloy concentrated preferentially to the surface of the grits to form a chromium-rich layer, and the hard joint between the alloy and the steel substrate is established through a cross-diffusion of iron and Ni-based alloy.

scholarly journals The Scanning Electron Microscope As A Precision Instrument

1996 ◽  
Vol 4 (6) ◽  
pp. 30-34
Author(s):  
Douglas Hansen
Keyword(s):  
Diffraction Gratings ◽  
Stray Field ◽  
X Ray Diffraction ◽  
Precision Instrument ◽  
X Ray ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
The University ◽  
Straight Lines ◽  
Scanning Electron

I began using scanning electron microscopes to solve problems encountered in the fabrication of x-ray diffraction gratings. Since these diffraction gratings consist of very regular lines and spaces, and produce high contrast images from the SEM. my microscopy work often points out problems with the microscope.One time, for example, I went to the university SEM lab I often use, and was advised that the microscope was down that day due to major field problems. This lab often had problems with stray fields for reasons no one could explain. Usually I was the only one to complain about stray field distortions since they are most obvious when imaging straight lines at high magnification, but on this occasion, the problem was serious and obvious to all.The microscope had just been serviced and as the lens coils had been replaced, they were expected to be the cause. The service technician was called in and determined that neither the coils nor the microscope electronics were the problem.

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