Frequency Effect of Torsion on Rotating Bending Fatigue Behavior of Gas Tungsten Arc (GTA) Welded AISI 1018 and AISI 4140 Welded Joints

2018 ◽  
Author(s):  
Saad Aziz ◽  
Ahmet Eren ◽  
Muhammad A. Wahab
Keyword(s):  
Fatigue Life ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Fatigue Behavior ◽  
Frequency Effect ◽  
Gas Tungsten Arc ◽  
Aisi 4140 ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Fatigue Life Reduction

Fatigue failures of welded structure are subjected to occur due to multiaxial fatigue load and torsion. In the current research work, the frequency effect of torsion on rotating bending fatigue load is analyzed on AISI 1018 steel and AISI 4140 steel. To perform rotating bending torsional fatigue test of welded and un-welded specimens, a unit was designed and manufactured. Gas Tungsten Arc (GTA) welding was carried out on round bar of AISI 1018 steel and AISI 4140 steel welded using ER70-S2 filler metal for welded specimen. Later, the influence of torsional frequency on rotating bending with torsion is analyzed on both base metal and welded structures. The frequency of torsion was applied on the specimens were - 500 cycle, 1000 cycle, 1500 cycle, 2000 cycle and 2500 cycle. From the analysis, fatigue life of AISI 1018 and AISI 4140 base metal specimens (rotating bending and torsion) were not affected when torsion was applied at different frequencies. However, fatigue behavior of welded AISI 1018 and AISI 4140 specimens were highly affected by the frequency of torsion. For torsion applied at every 500 cycles, 83.8% reduction of fatigue life was observed for AISI 1018 welded specimen with respect to AISI 1018 base metal specimens. In addition, torsion applied for every 1000, 1500, 2000, and 2500 cycles; 81.9%, 80%, 77.1%, and 72.4% reduction on fatigue life were observed for AISI 1018 welded specimen compare to AISI 1018 base metal specimens, respectively. Welded AISI 4140 specimens experienced less change in fatigue life compare to welded AISI 1018 specimens. For torsion applied at every 500 cycles, 73.9% fatigue life reduction was observed for welded AISI 4140 specimens compare to AISI 4140 base metal specimens. For torsion applied at every 1000, 1500, 2000, and 2500 cycles; 65.2%, 60.8%, 50%, and 43.5% fatigue life reduction occurred on welded AISI 1018 specimen. Moreover, hardness measurements for welded specimens of AISI 4140 and AISI 1018 were performed longitudinally. For welded AISI 1018 specimen, 14.8% and 9.7% hardness decrease was observed longitudinally compare to AISI 1018 base metal specimen at heat-affected zone (HAZ) and from heat-affected zone through weld zone, respectively. For welded AISI 4140 specimen, 26.3% reduction of hardness value was observed compare to AISI 4140 base metal through heat-affected zone for longitudinal analysis. Moreover, fracture surface analysis was performed on the welded and non-welded specimens to understand the fracture behavior.

Effects of Rotating-Bending and Torsional Fatigue Loads on Gas Tungsten Arc (GTA) Welded AISI 1018 Low Carbon Steel Joints

2015 ◽  
Author(s):  
M. W. Dewan ◽  
Gustavo González ◽  
M. A. Wahab
Keyword(s):  
Base Metal ◽  
Fatigue Behavior ◽  
Low Carbon Steel ◽  
Multiaxial Fatigue ◽  
Low Carbon ◽  
Gas Tungsten Arc ◽  
Biaxial Fatigue ◽  
Torsional Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

Most welded structures are subjected to multiaxial fatigue load and majority of the fatigue failure initiated from weld joints. Therefore, it is important to evaluate multiaxial fatigue behavior of commonly used welded materials. In the current investigations, the influence of rotating bending fatigue load along with torsional pulsed load was appraised for most commonly used AISI 1018 low carbon steel. A rotating-bending-torsional fatigue testing unit was designed and manufactured for biaxial fatigue test of welded and un-welded specimens. For welded specimens, Gas Tungsten Arc welding (also known as Tungsten-Inert-Gas (TIG) welding) was carried out on 19.05 mm diameter round bar of AISI 1018 steel using ER70-S2 filler metal. For rational comparison, only defects-free specimens were carefully chosen and tested. After welding, uniaxial tensile test was conducted to understand the fatigue loading criteria during rotating-bending fatigue test. Due to TIG welding, tensile strength was decreased considerably about 18% as compared to base metal. Rotating-bending (RB) and rotating-bending-torsional (RBT) fatigue tests were conducted to obtain a systematic understanding of biaxial fatigue behavior. RB fatigue life of welded specimens reduced compared to base metal as a result of complex thermal cycle during welding process and microstructural changes. Under combined loading conditions (RBT), base metal specimens did not exhibit significant difference on the fatigue behavior. However, for the welded specimens, the fatigue strength was reduced by about 12.8%. Moreover microstructural characterization and fracture surface analysis were performed to understand the fracture behavior of the tested specimens.

On the Effect of Electrodischarge Drilling on the Fatigue Life of Inconel 718

2014 ◽  
Vol 891-892 ◽  
pp. 1451-1456
Author(s):  
Elena Bassoli ◽  
Andrea Baldini ◽  
Andrea Gatto ◽  
Antonio Strozzi ◽  
Lucia Denti
Keyword(s):  
Fatigue Life ◽  
Inconel 718 ◽  
Metal Cutting ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Aerospace Applications ◽  
Rotating Bending Fatigue ◽  
Cutting Operation ◽  
Rotating Bending ◽  
Superposition Effect

Difficult-to cut-materials are associated with premature tool failure, most likely in the case of complex geometries and this shapes. However, Nickel-based alloys are commonly used in high-temperature and aerospace applications, where thin deep holes are often required. Then, the only viable manufacturing solution relies on non-contact processes, like electrodischarge (ED) drilling. Morphology of ED machined surfaces is significantly different than obtained by metal-cutting operation and is known to jeopardize fatigue strength, but the extent needs to be gauged and related to the process parameters. Aim of the paper is to study the effect of holes (0.8 mm diameter, aspect ratio 10) produced by ED drilling on the fatigue life of Inconel 718. Rotating bending fatigue tests are carried out on specimens drilled under two ED setups, as well as with a traditional cutting tool. Specimens free from holes are fatigued under the same conditions for comparison. Based on previous studies, extremal ED parameters are selected, giving best surface finish versus highest productivity. S-N curves show that the ED process causes a decrease of the fatigue resistance with respect to traditional drilling, whereas the effect of different ED setups is negligible. Maximum productivity can thus be pursued with no threat to fatigue performance. The fatigue limit variation is quantified by using the superposition effect principle: ED drilling causes an increase of the stress concentration factor around 25% if compared to traditional drilling. The macroscopic fatigue behavior is integrated with a study of the effects of the different drilling processes in the micro-scale, by means of a microstructural and fractographic analysis.

Improvement of Fatigue Behaviour of High Strength Aluminium Alloys by Fluidized Bed Peening (FBP)

2007 ◽  
Vol 344 ◽  
pp. 87-96 ◽  
Author(s):  
M. Barletta ◽  
F. Lambiase ◽  
Vincenzo Tagliaferri
Keyword(s):  
Fatigue Life ◽  
Fluidized Bed ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Maximum Amplitude ◽  
High Strength ◽  
Operational Parameters ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

This paper deals with a definition of a relatively novel technique to improve the fatigue behavior of high strength aluminum alloys, namely, Fluidized Bed Peening (FBP). Fatigue samples made from AA 6082 T6 alloy were chosen according to ASTM regulation about rotating bending fatigue test and, subsequently, treated by varying FBP operational parameters and fatigue testing conditions. First, a full factorial experimental plan was performed to assess the trend of number of cycles to rupture of fatigue samples varying among several experimental levels the factors peening time and maximum amplitude of alternating stress applied to fatigue samples during rotating bending fatigue tests. Second, design of experiment (DOE) technique was used to analyze the influence of FBP operational parameters on fatigue life of AA 6082 T6 alloy. Finally, ruptures of FB treated samples and untreated samples were discussed in order to evaluate the influence of operational parameters on the effectiveness of FBP process and to understand the leading process mechanisms. At any rate, the fatigue behavior of processed components was found to be significantly improved, thereby proving the suitability of FBP process as alternative mechanical technique to enhance fatigue life of components made from high strength aluminum alloy.

Effect of Shot Peening on Fatigue Behavior of AISI 4340 in Different Loading Conditions

2016 ◽  
Vol 713 ◽  
pp. 30-33 ◽  
Author(s):  
Marcelo A.S. Torres ◽  
D.T. Harada ◽  
Carlos Antonio Reis Pereira Baptista ◽  
Maria P. Cindra Fonseca
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Residual Stress Field ◽  
Surface Layers ◽  
Tension Tests ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Aisi 4340

Shot peening is a method widely used to improve the fatigue strength of materials, through the creation of a compressive residual stress field (CRSF) in their surface layers. In the present research the gain in fatigue life of AISI 4340 steel, obtained by shot peening treatment, is evaluated under the three different hardnesses used in landing gear. Rotating bending fatigue tests and alternating tension tests were conducted and the CRSF was measured by x-ray tensometry prior and after interrupted fatigue tests. The evaluation of fatigue life after shot peening in relation to the relaxation of CRSF, of the crack initiation sites and surface roughness is done.

scholarly journals Multiaxial Cycle Deformation and Low-Cycle Fatigue Behavior of Mild Carbon Steel and Related Welded-Metal Specimen

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Weilian Qu ◽  
Ernian Zhao ◽  
Qiang Zhou
Keyword(s):  
Fatigue Life ◽  
Base Metal ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Welding Process ◽  
Cyclic Hardening ◽  
Loading Conditions ◽  
Cycle Fatigue ◽  
Fatigue Life Reduction ◽  
The Given

The low-cycle fatigue experiments of mild carbon Q235B steel and its related welded-metal specimens are performed under uniaxial, in-phase, and 90° out-of-phase loading conditions. Significant additional cyclic hardening for 90° out-of-phase loading conditions is observed for both base metal and its related weldment. Besides, welding process produces extra additional hardening under the same loading conditions compared with the base metal. Multiaxial low-cycle fatigue strength under 90° out-of-phase loading conditions is significantly reduced for both base-metal and welded-metal specimens. The weldment has lower fatigue life than the base metal under the given loading conditions, and the fatigue life reduction of weldment increases with the increasing strain amplitude. The KBM, FS, and MKBM critical plane parameters are evaluated for the fatigue data obtained. The FS and MKBM parameters are found to show better correlation with fatigue lives for both base-metal and welded-metal specimens.

scholarly journals Properties of a thick-section narrow-gap gas tungsten arc weld of cast Haynes 282

2021 ◽  
Author(s):  
Michael Santella ◽  
X. Frank Chen ◽  
Philip Maziasz ◽  
Jason Rausch ◽  
Jonathan Salkin
Keyword(s):  
Base Metal ◽  
Heat Affected Zone ◽  
Reference Data ◽  
Filler Metal ◽  
Stress Rupture ◽  
Narrow Gap ◽  
Weld Deposit ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Weld Heat

AbstractA 50.8-mm-deep gas tungsten arc weld was made with matching filler metal in cast Haynes 282 alloy. The narrow-gap joint was filled with 104 weld beads. Visual and dye-penetrant inspection of cross-weld specimens indicated that the cast base metal contained numerous casting defects. No visible indications of physical defects were found in the weld deposit. The weld heat-affected zone was characterized by microcracking and localized recrystallization. The cause of the cracking could not be determined. Hardness testing showed that a softened region in the as-welded heat-affected zone was nearly eliminated by post-weld heat treatment. Tensile testing up to 816 °C showed that cross-weld specimen strengths ranged from 57 to 79% of the cast base metal tensile strength. The stress-rupture strengths of cross-weld specimens are within 20% of base metal reference data. Failures of both tensile and stress-rupture specimens occurred in the base metal.

High Cycle Fatigue Behavior of Thermally Oxidized Ti6Al4V Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 2179-2182 ◽  
Author(s):  
Mehmet Cingi ◽  
Onur Meydanoglu ◽  
Hasan Guleryuz ◽  
Murat Baydogan ◽  
Huseyin Cimenoglu ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Yield Strength ◽  
Thermal Oxidation ◽  
Fatigue Behavior ◽  
Surface Hardness ◽  
Ti6al4v Alloy ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Bending Fatigue Strength

In this study, the effect of thermal oxidation on the high cycle rotating bending fatigue behavior of Ti6Al4V alloy was investigated. Oxidation, which was performed at 600°C for 60 h in air, considerably improved the surface hardness and particularly the yield strength of the alloy without scarifying the tensile ductility. Unfortunately, the rotating bending fatigue strength at 5x106 cycles decreased from about 610 MPa to about 400 MPa upon oxidation. Thus, thermal oxidation leaded a reduction in the fatigue strength of around 34%, while improving the surface hardness (HV0.1) and yield strength 85 % and 36 %, respectively.

Fatigue Behavior of A5052 Aluminum Alloy with DLC/Thermally Sprayed WC-12Co Hybrid Coatings

2012 ◽  
Vol 538-541 ◽  
pp. 1693-1696 ◽  
Author(s):  
Y. Uematsu ◽  
T. Kakiuchi ◽  
Y. Kobayashi ◽  
Y. Harada
Keyword(s):  
Fatigue Behavior ◽  
Single Layer ◽  
Fatigue Tests ◽  
Hybrid Coating ◽  
Hybrid Coatings ◽  
Al Alloy ◽  
Dlc Film ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Thermally Sprayed

Rotating bending fatigue tests had been performed using A5052 aluminum (Al) alloy with the hybrid coatings which consisted of tungsten carbide including 12% cobalt (WC-12Co) interlayer and diamond-like carbon (DLC) film, in order to investigate the effect of hybrid coating on the fatigue behavior. The WC-12Co layer was thermally sprayed by a high velocity oxygen fuel (HVOF) method on A5052 with the thickness of 70, 120 or 170μm. Subsequently, the DLC film was deposited with the thickness of 15μm. The fatigue strengths of the specimens with WC-12Co single layer were higher than those of the substrate and increased with increasing the thickness of WC-12Co layer. The fatigue strengths of the specimens with the hybrid coating of 70μm WC-12Co interlayer and 15μm DLC film were better than those of the specimen with 70μm WC-12Co single layer. Thus the hybrid coating structure was effective to improve fatigue strengths. However the beneficial effect of hybrid coating was not apparent in the specimens with thicker WC-12Co interlayer of 120 and 170μm.

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