Comparison Between EBW and GTAW for Turmo IV C Compressor Blade Repairs

1995 ◽  
Vol 117 (3) ◽  
pp. 545-553
Author(s):  
W. Miglietti
Keyword(s):  
Electron Beam Welding ◽  
Weld Zone ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Parent Metal ◽  
Compressor Blades ◽  
Metallographic Examination ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Stringent Test

A research study was undertaken to evaluate whether electron beam welding (EBW) or gas tungsten arc welding (GTAW) could be utilized for repairs to the leading edges of the Turmo IV C compressor blades. These blades are manufactured from Ti-6Al-4V. The study entailed performing a series of welding trials. For the GTAW process a matching filler metal to the parent metal was used, whereas for the EBW process, the welds were made autogenously. After metallographic examination of the weld microstructure, mechanical property assessments were undertaken, namely tensile and fatigue tests, the latter being a stringent test to evaluate the performance of the welded joint. The results demonstrated that the EB welds had equivalent properties to the parent metal, whereas the GTA welds had poorer fatigue properties due to undesirable microstructure that resulted in the weld zone. The results achieved herein showed that the EBW process would be an appropriate technique for the restoration of these compressor blades.

scholarly journals Comparison Between EBW and GTAW for TURMO IV C Compressor Blade Repairs

1994 ◽  
Author(s):  
W. Miglietti
Keyword(s):  
Electron Beam Welding ◽  
Weld Zone ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Parent Metal ◽  
Compressor Blades ◽  
Metallographic Examination ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Stringent Test

A research study was undertaken to evaluate whether electron beam welding (EBW) or gas tungsten arc welding (GTAW) could be utilised for repairs to the leading edges of the Turmo IV C compressor blades. These blades are manufactured from Ti-6Al-4V. The study entailed performing a series of welding trials. For the GTAW process a matching filler metal to the parent metal was used whereas for the EBW process, the welds were made autogenously. After metallographic examination of the weld microstructure, mechanical property assessments were undertaken, namely tensile and fatigue tests, the latter being a stringent test to evaluate the performance of the welded joint. The results demonstrated that the EB welds had equivalent properties to the parent metal whereas the GTA welds had poorer fatigue properties due to undesirable microstructure that resulted in the weld zone. The results achieved herein showed that the EBW process would be an appropriate technique for the restoration of these compressor blades.

Feasibility of Extending Current Allowable Weld Repairs for a Compressor Impeller

1995 ◽  
Author(s):  
W. Miglietti ◽  
F. Jacobs
Keyword(s):  
Fatigue Tests ◽  
Element Analysis ◽  
Metallographic Examination ◽  
Gas Tungsten Arc ◽  
Sand Erosion ◽  
Compressor Impeller ◽  
Gtaw Process ◽  
Leading Edges ◽  
Equivalent Properties ◽  
Weld Heat

This research study was undertaken to evaluate whether gas tungsten arc welding (GTAW) could be utilised to extend the limits of an existing repair scheme. The compressor impeller of the GTC 85-71 suffers from such severe sand erosion to the leading edges, that the damage exceeds the manufacturers specification. The impeller is manufactured from Ti-6Al-4V. The study entailed performing a series of welding trials and post-weld heat treatments. After metallographic examination of the weld microstructure, mechanical property assessments (i.e. tensile and fatigue tests) were undertaken. The results demonstrated that the welds after the 550 °C/8 hr post-weld heat treatment had equivalent properties to those of the parent metal. The stress distribution determined by finite element analysis showed the weld to be in an area of low stress. The results achieved herein and the stress analysis showed that the GTAW process is feasible for extending the repair limits for restoration of the leading edges of the compressor impeller.

Evaluation of High Cycle Fatigue Properties of Double Side Welded AISI 321 Plates Using GTAW Process for Pressure Vessels

2021 ◽  
Author(s):  
Mohan Kumar S ◽  
A. Rajesh Kannan ◽  
Pramod R. ◽  
Pravin Kumar N ◽  
Nallathambi Siva Shanmugam ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Fatigue Behavior ◽  
Fatigue Behaviour ◽  
Pressure Vessels ◽  
Fatigue Properties ◽  
Dendritic Microstructure ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Fatigue Rupture ◽  
Aisi 321

Abstract Titanium stabilized AISI 321 material (UNS S32100) is generally preferred in the pressure vessel industry as they are not sensitive to intergranular corrosion. In critical applications, the fatigue behaviour of weld seams are amongst the most stringent requirements. The microstructural characteristics and fatigue performance of double side welded AISI 321 plate having 6 mm thickness were evaluated in this work. AISI 321 was welded with Double side-gas tungsten arc welding (DS-GTAW) process. The fatigue behavior was examined under a loading ratio of 0.1 for two different specimens: Base metal (BM) and Weld metal (WM). Monotonic tensile results show the improved tensile properties of WM compared to BM samples. The fatigue strength of WM (332.6 MPa) was 25% higher than that of BM (265.7 MPa) specimen and is attributed to the increase in ferrite volume along with dendritic microstructure. The change in the fraction of low angle grain boundaries (LABs) and high angle grain boundaries (HABs) improved the tensile and fatigue properties. The stress amplitudes influenced the degree of striations in the BM and WM. Final fracture surfaces were characterized with dimples and micro-voids, revealing the ductile mode of fatigue fracture. The fatigue rupture surfaces of BM and WM samples at different stress regimes are discussed.

The fatigue life of a friction stir welded 19501 aluminium alloy T-joint

2018 ◽  
Vol 27 (1-2) ◽  
Author(s):  
Prakash Chandra Gope ◽  
Harshit Kumar ◽  
Himanshu Purohit ◽  
Manish Dayal
Keyword(s):  
Aluminium Alloy ◽  
Weld Zone ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Test Results ◽  
Element Analysis ◽  
Friction Stir ◽  
Fracture Surfaces ◽  
Proposed Model ◽  
Stress Ratios

AbstractFriction stir welding (FSW) is a solid-state joining which reduces the structural weight significantly and hence it has received worldwide attention for the joining of aluminium alloys. In this paper, fatigue tests and finite element analysis were employed to study the mechanical and fatigue properties of a friction stir welded T-joint of 19501 aluminium alloy. An LS-2 FSW machine with 100 kN capacity was used to fabricate the T and butt joints. The tensile properties of the friction stir welded joint show that there is a marginal reduction of about 5% in strength and ductility as compared to an un-welded 19501 aluminium alloy. S-N test results of theT-joint specimen at two stress ratios of 0 and −1 showed that there was a reduction of 15% in the fatigue strength due to the change of stress ratio from 0 to −1. The effect of mean stress can be well approximated using Goodman’s criterion as compared to Gerber’s or Soderberg’s criteria. The predicted fatigue lives from the proposed model using the Palmgren-Miner rule (PMR) were found to be within reasonable accuracy. Micrographs shown for the fracture surfaces of the retreating side, mid-weld zone and the advancing side of the T-joint indicate that fracture surfaces are a mixture of dimple and cleavage features.

scholarly journals Fatigue Properties of AZ31B Magnesium Alloy Processed by Equal-Channel Angular Pressing

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1191
Author(s):  
Ryuichi Yamada ◽  
Shoichiro Yoshihara ◽  
Yasumi Ito
Keyword(s):  
Magnesium Alloy ◽  
Equal Channel Angular Pressing ◽  
Low Cycle Fatigue ◽  
Annealed Sample ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Angular Pressing ◽  
Fundamental Research ◽  
Number Of Cycles ◽  
Biodegradable Magnesium

A stent is employed to expand a narrowed tubular organ, such as a blood vessel. However, the persistent presence of a stainless steel stent yields several problems of late thrombosis, restenosis and chronic inflammation reactions. Biodegradable magnesium stents have been introduced to solve these problems. However, magnesium-based alloys suffer from poor ductility and lower than desired fatigue performance. There is still a huge demand for further research on new alloys and stent designs. Then, as fundamental research for this, AZ31 B magnesium alloy has been investigated for the effect of equal-channel angular pressing on the fatigue properties. ECAP was conducted for one pass and eight passes at 300 °C using a die with a channel angle of 90°. An annealed sample and ECAP sample of AZ31 B magnesium alloy were subjected to tensile and fatigue tests. As a result of the tensile test, strength in the ECAP (one pass) sample was higher than in the annealed sample. As a result of the fatigue test, at stress amplitude σa = 100 MPa, the number of cycles to failure was largest in the annealed sample, medium in the ECAP (one pass) sample and lowest in the ECAP (eight passes) sample. It was suggested that the small low cycle fatigue life of the ECAP (eight passes) sample is attributable to severe plastic deformation.

scholarly journals Arc Characteristics and Weld Bead Microstructure of Ti-6Al-4V Titanium Alloy in Ultra-high Frequency Pulse Gas Tungsten Arc Welding (UHFP-GTAW) Process

2020 ◽  
Vol 26 (4) ◽  
pp. 426-431
Author(s):  
Wei LI ◽  
Gaochong LV ◽  
Qiang WANG ◽  
Songtao HUANG
Keyword(s):  
Titanium Alloy ◽  
Fusion Zone ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Weld Bead ◽  
Gas Tungsten Arc ◽  
Arc Characteristics ◽  
Arc Pressure ◽  
Gtaw Process ◽  
Gas Tungsten

To resolve the problem of grain coarsening occurring in the fusion zone and the heat-affected zone during conventional gas tungsten arc welding(C-GTAW) welded titanium alloy, which severely restricts the improvement of weld mechanical properties, welding experiments on Ti-6Al-4V titanium alloy by adopting ultra-high frequency pulse gas tungsten arc welding (UHFP-GTAW) technique were carried out to study arc characteristics and weld bead microstructure. Combined with image processing technique, arc shapes during welding process were observed by high-speed camera. Meanwhile the average arc pressure under various welding parameters were obtained by adopting pressure measuring equipment with high-precision. In addition, the metallographic samples of the weld cross section were prepared for observing weld bead geometry and microstructure of the fusion zone. The experimental results show that, compared with C-GTAW, UHFP-GTAW process provides larger arc energy density and higher proportion of arc core region to the whole arc area. Moreover, UHFP-GTAW process has the obviously effect on grain refinement, which can decrease the grain size of the fusion zone. The results also revealed that a significant increase of arc pressure while increasing pulse frequency of UHFP-GTAW, which could improve the depth-to-width ratio of weld beads.

Fatigue Behaviour of Friction Stir Welded Steel Joints

2014 ◽  
Vol 891-892 ◽  
pp. 1488-1493 ◽  
Author(s):  
José Azevedo ◽  
Virgínia Infante ◽  
Luisa Quintino ◽  
Jorge dos Santos
Keyword(s):  
Base Material ◽  
Welding Process ◽  
Steel Structures ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Welded Steel ◽  
Shipbuilding Industry ◽  
Friction Stir ◽  
Steel Joints

The development and application of friction stir welding (FSW) technology in steel structures in the shipbuilding industry provide an effective tool of achieving superior joint integrity especially where reliability and damage tolerance are of major concerns. Since the shipbuilding components are inevitably subjected to dynamic or cyclic stresses in services, the fatigue properties of the friction stir welded joints must be properly evaluated to ensure the safety and longevity. This research intends to fulfill a clear knowledge gap that exists nowadays and, as such, it is dedicated to the study of welded steel shipbuilding joints in GL-A36 steel, with 4 mm thick. The fatigue resistance of base material and four plates in as-welded condition (using several different parameters, tools and pre-welding conditions) were investigated. The joints culminate globally with defect-free welds, from which tensile, microhardness, and fatigue analyses were performed. The fatigue tests were carried out with a constant amplitude loading, a stress ratio of R=0.1 and frequency between 100 and 120 Hz. The experimental results show the quality of the welding process applied to steel GL-A36 which is reflected in the mechanical properties of joints tested.

Effect of Pre-Strain and Roller Working on Torsional Fatigue Properties of a Structural Steel

2011 ◽  
Vol 295-297 ◽  
pp. 2227-2230
Author(s):  
Cong Ling Zhou
Keyword(s):  
Residual Stress ◽  
Fatigue Limit ◽  
Work Hardening ◽  
Compressive Residual Stress ◽  
Strain Ratio ◽  
Fatigue Tests ◽  
The Other ◽  
Fatigue Properties ◽  
Torsional Fatigue ◽  
Stress Work

In this study, fatigue tests have been performed using two kinds of specimens made of 25 steel. One is pre-strained specimen with pre-strain ratio changing from 2% to 8% by tension, the other is roller worked with deformation of 0.5 mm and 1.0 mm in diameter direction. In the case of pre-strained specimen, the fatigue limit increases according to increase of tensile pre-strain, the fatigue limit of 8% pre-strained specimen is 25% higher than that of non-pre-strained one; in the case of roller worked specimen, the fatigue limit of R05 and R10 is 126% and 143% to that of non-roller worked specimen, respectively. These remarkable improvements of fatigue limit would be caused by the existence of compressive residual stress, work-hardening and the elongated microscopic structures.

scholarly journals Metallurgical and Mechanical Research on Dissimilar Electron Beam Welding of AISI 316L and AISI 4340

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
A. R. Sufizadeh ◽  
S. A. A. Akbari Mousavi
Keyword(s):  
Electron Beam ◽  
Electron Beam Welding ◽  
Weld Zone ◽  
Tensile Tests ◽  
Beam Current ◽  
Aisi 316L ◽  
Cooling Rates ◽  
Minimum Width ◽  
Optimum Sample ◽  
Aisi 4340

Dissimilar electron beam welding of 316L austenitic stainless steel and AISI 4340 low alloy high strength steel has been studied. Studies are focused on effect of beam current on weld geometry, optical and scanning electron microscopy, X-ray diffraction of the weld microstructures, and heat affected zone. The results showed that the increase of beam current led to increasing depths and widths of the welds. The optimum beam current was 2.8 mA which shows full penetration with minimum width. The cooling rates were calculated for optimum sample by measuring secondary dendrite arm space and the results show that high cooling rates lead to austenitic microstructure. Moreover, the metallography result shows the columnar and equiaxed austenitic microstructures in weld zone. A comparison of HAZ widths depicts the wider HAZ in the 316L side. The tensile tests results showed that the optimum sample fractured from base metal in AISI 316L side with the UTS values is much greater than the other samples. Moreover, the fractography study presents the weld cross sections with dimples resembling ductile fracture. The hardness results showed that the increase of the beam current led to the formation of a wide softening zone as HAZ in AISI 4340 side.

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