Microstructural and mechanical characterization of the effect of the welding process on creep behavior of welded joint and base metal specimens of Inconel 600

MRS Advances ◽  
2020 ◽  
Vol 5 (59-60) ◽  
pp. 3003-3014
Author(s):  
Lourdes Y. Herrera-Chávez ◽  
Alberto Ruiz ◽  
Víctor H. López-Morelos ◽  
Carlos Rubio-González ◽  
Martín R. Barajas-Álvarez ◽  
...  
Keyword(s):  
Base Metal ◽  
Creep Behavior ◽  
Heat Affected Zone ◽  
Structural Integrity ◽  
Welded Joint ◽  
Welding Process ◽  
Creep Tests ◽  
Inconel 600 ◽  
Two Temperatures

AbstractIn this study, plates of Inconel 600 superalloy were gas metal arc welded to investigate the effects of the welding process on the creep behavior of the welded samples and compare it to the creep behavior of samples in the as-received condition. Creep tests were performed at two temperatures (600 and 650 °C) with different stress levels. During the welding process, three distinctive microstructural zones are generated, i.e. welded material, heat affected zone, and base metal that may affect the properties of the welded joint. Microstructural, elemental analysis of samples was conducted using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The experimental results show that creep rupture preferentially occurs in the heat-affected zone of the base metal at 4 mm from the fusion line and that the creep behavior of welded samples is different from that of the base metal. These results can be used in the design of structural components to assure their structural integrity.

scholarly journals Study of Laser Welding of HCT600X Dual Phase Steels

2014 ◽  
Vol 22 (1) ◽  
pp. 93-98
Author(s):  
Pavol Švec ◽  
Viliam Hrnčiar ◽  
Alexander Schrek
Keyword(s):  
Tensile Strength ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welding Speed ◽  
Welding Process ◽  
Beam Power ◽  
Welding Parameters ◽  
Dual Phase ◽  
Welded Steel ◽  
Steel Sheets

AbstractThe effects of beam power and welding speed on microstructure, microhardnes and tensile strength of HCT600X laser welded steel sheets were evaluated. The welding parameters influenced both the width and the microstructure of the fusion zone and heat affected zone. The welding process has no effect on tensile strength of joints which achieved the strength of base metal and all joints fractured in the base metal.

Experimental and Numerical Evaluation of Fracture Toughness on Electron Beam Welded Joint in Al6061-T6

2016 ◽  
Author(s):  
W. Rekik ◽  
O. Ancelet ◽  
C. Gardin ◽  
F. Hamon
Keyword(s):  
Electron Beam ◽  
Mechanical Behavior ◽  
Yield Stress ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Material Behavior ◽  
Failure Assessment ◽  
Tearing Resistance ◽  
Alloy 6061

In order to ensure the integrity of structures, failure assessment is required. In this context, the fracture behavior of an electron beam (EB) welded joint on thick plate of aluminum alloy 6061-T6 used for structural components of experimental nuclear reactors was investigated. In the particular case of welded structures, the tearing resistance is strongly dependent on the mismatch of the welded joint and the local behavior of each metallurgical zone. For a reliable analysis, the tensile mechanical behavior of each position of the welded joint was precisely determined by the use of a new measurement prototype. The toughness behavior under different configurations was then evaluated on CT specimens. From these experimental results a mechanical behavior contrast was highlighted. In fact, the fusion zone presents the lowest yield stress and a gradient is observed in the heat affected zone until the material behavior reaches of the base metal yield stress. On the contrary, the toughness of the welded zone is the highest and decreases strongly in the heat affected zone according to an exponential function until the base metal toughness is reached.

Application of FIB/SEM/EBSD for Evaluation of Residual Strains and Their Relationship to Weld Metal Hydrogen Assisted Cold Cracking

2012 ◽  
Author(s):  
W. L. Costin ◽  
I. H. Brown ◽  
L. Green ◽  
R. Ghomashchi
Keyword(s):  
Residual Stresses ◽  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Ion Beam ◽  
Base Material ◽  
Welding Process ◽  
Cold Cracking ◽  
Predictive Methods ◽  
Residual Strains

Hydrogen assisted cold cracking (HACC) is a welding defect which may occur in the heat affected zone (HAZ) of the base metal or in the weld metal (WM). Initially the appearance of HACC was associated more closely with the HAZ of the base metal. However, recent developments in advanced steel processing have considerably improved the base material quality, thereby causing a shift of HACC to the WM itself. This represents a very serious problem for industry, because most of the predictive methods are intended for prevention of HACC in the HAZ of the base metal, not in the weld metal [1]. HACC in welded components is affected by three main interrelated factors, i.e. a microstructure, hydrogen concentration and stress level [2–4]. In general, residual stresses resulting from the welding process are unavoidable and their presence significantly influences the susceptibility of weld microstructures to cracking, particularly if hydrogen is introduced during welding [5]. Therefore various weldability tests have been developed over the years which are specifically designed to promote HACC by generating critical stress levels in the weld metal region due to special restraint conditions [4, 6–8]. These tests were used to develop predictive methods based on empirical criteria in order to estimate the cracking susceptibility of both the heat-affected zone and weld metal [4]. However, although the relationship between residual stress, hydrogen and HACC has received considerable attention, the interaction of residual stresses and microstructure in particular at microscopic scales is still not well understood [5, 9–21]. Therefore the current paper focuses on the development and assessment of techniques using Focused Ion Beam (FIB), Scanning Electron Microscopy (SEM) and Electron Backscatter Diffraction for the determination of local residual strains at (sub) micron scales in E8010 weld metal, used for the root pass of X70 pipeline girth welds, and their relationship to the WM microstructure. The measurement of these strains could be used to evaluate the pre-existing stress magnitudes at certain microstructural features [22].

Investigations on Laser-TIG Hybrid Welding of Magnesium Alloys

2005 ◽  
Vol 488-489 ◽  
pp. 371-376 ◽  
Author(s):  
Gang Song ◽  
Li Ming Liu ◽  
Mingsheng Chi ◽  
Ji Feng Wang
Keyword(s):  
Magnesium Alloys ◽  
Fusion Zone ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welding Process ◽  
Large Change ◽  
Tig Welding ◽  
Al Content ◽  
Β Phase ◽  
Cast Magnesium

This paper presents results of recent investigations on the weldability of several wrought (AZ31, AZ61) and cast magnesium-based alloys (AZ91) by laser-TIG welding process. The investigations showed that magnesium alloys can be easily welded by laser-TIG welding. The grain of the fusion zone was finer than that of in base metal. The width of the heat-affected zone welded by laser-TIG welding process was obviously narrower than that of welded by TIG. Besides, with the Al content of magnesium alloys increasing, the width of the heat-affected zone (HAZ) was increased，as well as the content of β phase(Mg17Al12). The hardness in the fusion zone (FZ) and in HAZ of AZ61 and AZ91 has a large change to the base metal due to the existing of β phase, while no change relative for AZ31. It results from above discussing that laser-TIG welding is an excellent welding process for magnesium alloys.

scholarly journals MODELING THE WORK OF THE HEAD OF A HYDROMECHANICAL EXPANDER FOR WELDED PIPES OF A LARGE DIAMETER

2020 ◽  
pp. 35-42
Author(s):  
L. M. Gurevich ◽  
V. F. Danenko ◽  
A. A. Istrati ◽  
V. A. Sonnova
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Internal Pressure ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Large Diameter ◽  
Design Parameters ◽  
Maximum Stresses ◽  
Distribution Of Stresses

Finite element simulates of changing stresses and strains under loading by gradually increasing internal pressure of cylindrical welded vessels was carried out. The vessels had an annular mechanically inhomogeneous welded joint with different mechanical properties of the joint, heat-affected zone, and base metal. Maximum stresses developed in the caps of the vessels, and the annular joint are lightly loaded. The distribution of stresses and strains in joint at various design parameters of the vessels is investigated.

scholarly journals PENGARUH MEDIA PENDINGINAN TERHADAP KEKERASAN DAN STRUKTUR MIKRO HASIL PENGELASAN OXY ACETYLENE PADA MATERIAL BAJA ST-37

2017 ◽  
Vol 5 (2) ◽  
Author(s):  
Made Angga Priadi ◽  
I Nyoman Pasek Nugraha ◽  
Gede Widayana
Keyword(s):  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Quantitative Research ◽  
Welding Process ◽  
Air Cooling ◽  
Water Cooling ◽  
Independent Variable ◽  
The Mean ◽  
Cooling Media

Media pendingin merupakan suatu substansi yang berfungsi dalam menentukan kecepatan pendinginan yang dilakukan terhadap material yang telah diuji dalam perlakuan panas. Penelitian ini bertujuan untuk mengetahui tingkat kekerasan dan pengamatan struktur mikro material baja ST-37 yang dipengaruhi media pendinginan air, udara dan oli serta penelitian ini dapat memberikan bahan referensi bagi lingkup pendidikan teknik mesin dan sebagai acuan di dunia industri dalam menggunakan media pendingin pada proses pengelasan. Adapun jenis metode yang digunakan dalam penelitian ini adalah metode penelitian eksperimen. Terdapat dua jenis variable yang digunakan dalam penelitian ini yaitu variabel bebas yang berupa media pendingin air, media pendingin udara dan media pendingin oli dan variabel terikatnya berupa sifat kekerasan. Dari hasil penelitian yang telah dilakukan dimana kekerasan daerah logam induk dengan media pendingin air memperoleh nilai rata-rata sebesar 63,10 Kg/mm2, pendingin udara memperoleh nilai rata-rata sebesar 65,61 Kg/mm2, dan media pendingin oli memperoleh nilai rata-rata sebesar 62,68 Kg/mm2. Kekerasan pada daerah HAZ dengan media pendingin air memperoleh nila rata-rata sebesar 68,49 Kg/mm2, media pendingin udara memperoleh nilai rata-rata sebesar 71,05 Kg/mm2 dan media pendingin oli memperoleh nilai rata-rata sebesar 70,34 Kg/mm2. Kekerasan pada daerah logam las dengan media pendingin air memperoleh nilai rata-rata sebesar 60,99 Kg/mm2, media pendingin udara memperoleh nilai rata-rata sebesar 61,79 Kg/mm2 dan media pendingin oli memperoleh nilai rata-rata sebesar 60,79 Kg/mm2. Berdasarkan dari hasil yang telah didapatkan baik pada logam induk, daerah HAZ dan logam Las dimana tingkat kekerasan yang lebih baik diperoleh dari proses pendinginan udara dibandingkan dengan media pendingin air dan media pendingin oli dari proses pengelasan oxy acytelene.Kata Kunci : Baja ST-37, Kekerasan Material, media pendinginan. The cooling media is a substance which has a function to determine the speed refrigeneration which carried out of the material that has been tasted by heat treatment. The objective of the research is to know the level of hardness and the observation of steel ST-37 material which is affected by cooling media such as water, air, and oil. Also this research may give a reference for Engineering Department of Education and industry in using cooling media for welding process. There is a method that use in this research, that is called quantitative research. There are two variables that use in this research. Independent variable and dependent variable. An independent variable are water, air, and oil cooling media. On the other hand, a dependent variable is nature of hardness. In this research the researcher got a results where the mean of hardness of the base metal area with the water cooling media is 63.10 Kg/mm2, in air conditioning is 61Kg/mm2, and the oil cooling is 62.68 Kg/mm2. The mean of a hardness in Heat Affected Zone (HAZ) by water cooling media 68,49 Kg/mm2, air cooling media is 71,05 Kg/mm2 and an air cooling is 70,34 Kg/mm2. The mean of Hardness in the weld metal area with water cooling media is 60,99 Kg/mm2, air-cooling media is 61,79 Kg/mm2 and oil-cooling media is 60,79Kg/mm2. Based on the result which has been gotten from base metal, Heat Affected Zone (HAZ), and weld metal where the best hardness level is obtained from air-cooling process rather than water cooling media and oil cooling media from oxy acytelene welding process.keyword : Cooling media, steel ST-37, hardness properties.

scholarly journals Shielded Metal Arc and Thermite Welding Effect to Residual Stress, Hardness and Crack of R54-Rail Weld Joint

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Yurianto ◽  
Gunawan Dwi Haryadi ◽  
Sri Nugroho ◽  
Sulardjaka ◽  
Susilo Adi Widayanto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Welding Process ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Crack Susceptibility

The heating and cooling at the end of the welding process can cause residual stresses that are permanent and remain in the welded joint. This study aims to evaluate the magnitude and direction of residual stresses on the base metal and heat-affected zone of rail joints welded by the manual shielded metal arc and thermite welding. This research supports the feasibility of welding for rail. The material used in this study is the R-54 rail type, and the procedure used two rail samples of one meter long each, welded using manual shielded metal arc welding and thermite welding. The base metal and heat-affected zone of the welded joints were scanned with neutron ray diffraction. The scan produces a spectrum pattern and reveals the direction of the residual stress along with it. We found the strain value contained in both types of welded joints by looking at the microstrain values, which we obtained using the Bragg equation. The results show that the magnitude and direction of the residual stress produced by manual shielded metal arc welding and thermite welding are not the same. Thermite welding produces lower residual stress (lower crack susceptibility) than manual shielded metal arc welding. The melt's freezing starts from the edge to the center of the weld to create random residual stresses. The residual stress results of both the manual shielded metal arc welding and thermite welding are still below the yield strength of the base metal.

Region-Specified Ratcheting Behavior of API X80 Welded Joint Under Uniaxial Cyclic Loading

2016 ◽  
Author(s):  
Hongsheng Lu ◽  
Yonghe Yang ◽  
Gang Chen ◽  
Xu Chen ◽  
Xin Wang
Keyword(s):  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Pipeline Steel ◽  
Coarse Grained ◽  
Strain Accumulation ◽  
Lower Strength ◽  
Fine Grained ◽  
Ratcheting Strain

Evaluation of mechanical performance of different regions can be difficult by using standard size samples due to the size limitation of weld metal and heat-affected zone (HAZ). At first, the microstructure of different regions was characterized and quantified by Scanning Electron Microscope, which indicate that the pipeline steel is a typical acicular ferrite steel. In this study the deformation behavior of different regions (base metal, weld metal and heat affected zone) in a welded joint of API X80 pipeline steel were studied by conducting uniaxial loading tests on miniature specimens with the cross section of 2×0.5mm and gauge length of 9mm. From the results of uniaxial tension in base metal and weld metal it is shown that the welding is overmatching. Compared to the base metal, the coarse grained HAZ exhibits a lower strength, while the fine grained HAZ exhibits a higher strength. Under near zero-to-tension cyclic stress loading, all regions of the welded joints exhibit progressive accumulation of plastic strain. Under the same stress level, the base metal shows the fastest ratcheting strain accumulation, which is the result of lower strength than other regions. This fact may indicate that the ratcheting behavior of the overall welded joint is highly dependence on that of base metal for the present case. But when under the same normalized stress level (σ = σ/σYS), the fine grained HAZ has the highest ratcheting strain accumulation, while the coarse grained HAZ has the lowest ratcheting strain accumulation, which reveals that the intrinsic resistance to ratcheting is yield strength dependent.

Research on Microstructure and Properties of Welded Joint of 2205 Steel with FCAW

2011 ◽  
Vol 391-392 ◽  
pp. 763-767
Author(s):  
Li Yang ◽  
Na Zhang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
High Strength ◽  
Two Phase ◽  
Flux Cored Arc Welding ◽  
Mechanical Properties And Corrosion

On the basis of the analysis of composition, microstructure, properties and weldability of 2205 duplex stainless steel, the flux cored arc welding (FCAW) process is made. Then the microstructure, mechanical properties and corrosion resistance of welded joint were analyzed. The results shows using FCAW process, in order to obtain high strength, perfect impact toughness and overall and partial resistance to stress corrosion in welded joint, the Ni content of duplex stainless steel welding material should be 2% to 4% higher than that of base metal, multi-layer and multi-channel welding is adopted with the strict control of energy input less than or equal to 0.926KJ/mm, layer temperature is less than 120 °C, thus the appropriate proportion of two-phase structure in the welded joint can be got. Using a reasonable welding procedure, the microstructure in weld beam is austenite (A) + ferrite (F), and in heat affected zone is ferrite (F) + austenite (A) + a small amount of third phase, the content of austenite in weld beam and heat affected zone is higher than that of the base metal. Tensile strength of the welded joint is up to 854.5MPa and the fracture occurs in the base metal and the heat affected zone. The welded joint has high strength, good plasticity, toughness and corrosion resistance.

scholarly journals Weld Formation in Laser Hot-Wire Welding of 7075 Aluminum Alloy

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 909 ◽  
Author(s):  
Shichun Li ◽  
Wei Xu ◽  
Gang Xiao ◽  
Bing Chen
Keyword(s):  
Aluminum Alloy ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Weld Zone ◽  
Welding Process ◽  
Tensile Fracture ◽  
Hot Wire ◽  
Columnar Crystal ◽  
Weld Formation ◽  
Hot Wire Welding

The laser hot-wire welding process was adopted to weld 7075 high-strength aluminum alloy. The influence laws of parameters on the weld formation were analyzed during laser hot-wire welding, and the microstructure characteristics and mechanical properties of welds were analyzed. The results showed that the parameters whose significance of influence on weld formation as ranked from high to low were laser power, current, gap width, welding speed and wire feeding rate. With the increase of wire temperature, the weld formation quality became better initially and then worse. Under the condition of optimized parameters, good weld formation could be obtained. The weld zone had a fine grain microstructure, and was in casting state consisted of dendritic crystal and equiaxed crystal. The heat affected zone mainly consisted of columnar crystal. The microhardness decreased gradually from base metal to heat affected zone then to weld zone. The tensile fracture of weld specimen occurred at the weld zone, and was in the ductile fracture state. The tensile strength of weld joint was 206 MPa and was 64.2% of base metal strength.

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