Microstructure, mechanical and corrosion properties of TIG welded Hastelloy C-276

2020 ◽  
Vol 62 (9) ◽  
pp. 883-887
Author(s):  
Mustafa Tümer
Keyword(s):  
Weld Metal ◽  
Potentiodynamic Polarization ◽  
Base Material ◽  
Corrosion Properties ◽  
Gas Tungsten Arc ◽  
Industrial Alloy ◽  
Weld Metal Microstructure ◽  
Mechanical And Corrosion Properties ◽  
Metal Microstructure ◽  
The Impact

Abstract Hastelloy C-276 is a corrosion resistant nickel based solid solution hardened industrial alloy which has superior mechanical and corrosion properties. In this study, Hastelloy C-276 alloy was welded via the GTAW (Gas tungsten arc welding) method using ERNiCrMo-4 filler metal. Tensile, bending and notch impact tests were performed to determine the mechanical properties. The microstructure of the weld metal was investigated by light microscopy (LM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The impact toughness values of the heat affected zone (HAZ) showed a better performance than those of the weld metal. In addition, the corrosion properties of the weld metal and the base material were investigated by potentiodynamic polarization tests. Electrochemical potentiodynamic polarization parameters were determined according to corrosion behavior and microstructure properties. In particular, the corrosion rate of the weld metal increased because of the Mo-rich phases deposited in the weld metal microstructure.

Effect of Ti on the Microstructures and Toughness of TMCP-600 Steel Weld Metals

2013 ◽  
Vol 746 ◽  
pp. 462-466
Author(s):  
Jin Hyun Koh ◽  
Bok Su Jang
Keyword(s):  
Weld Metal ◽  
Impact Energy ◽  
Acicular Ferrite ◽  
Gas Metal Arc Welding ◽  
Control Process ◽  
High Strength ◽  
Weld Metal Microstructure ◽  
Metal Microstructure ◽  
The Impact ◽  
Ti Content

The Ti addition effect on the characteristics of weld metal, such as impact energy, microstructure and nonmetallic inclusions, was investigated to develop a suitable gas metal arc welding wire for the high strength of TMCP (Thermo Mechanical Control Process)-600 steel. The fraction of acicular ferrite which was known to be a favorable weld metal microstructure for toughness was increased with Ti content from 0.002% to 0.025%, The impact energy of weld metal was increased whereas the ductile to brittle transition temperature was decreased with increasing Ti content. The size of nonmetallic inclusion was decreased while the density of inclusions was decreased with increasing Ti content. It was found that Ti content on the weld metal toughness had a plus effect by increasing the fraction of acicular ferrite in the weld metal microstructure.

Modelling of Dilution Effects on Microstructure and Residual Stress in a Multi-Pass Weldment

2018 ◽  
Author(s):  
Yongle Sun ◽  
C. J. Hamelin ◽  
M. C. Smith ◽  
A. N. Vasileiou ◽  
T. F. Flint ◽  
...  
Keyword(s):  
Residual Stress ◽  
Weld Metal ◽  
Phase Distribution ◽  
Measurement Data ◽  
Base Material ◽  
Cross Sectional ◽  
Gas Tungsten Arc ◽  
Compressive Stresses ◽  
Thermal Solution ◽  
Dilution Effects

Three-pass gas tungsten arc welding in a 20-mm thick SA508 steel plate is modelled using a sequentially coupled thermal-metallurgical-mechanical model. The dilution for each pass is estimated as the proportion of base material in the weld metal, based on an analysis of the cross-sectional area of each fusion zone. The thermal solution of the weld model is validated using thermocouple measurement data and cross-weld macrographs. The predicted microstructure is qualitatively compared with that observed in cross-weld optical micrographs. The measured hardness distribution is used to quantitatively validate the post-weld ferritic phase distribution (e.g. the ferrite, bainite and martensite fractions), based on a hardness-microstructure correlation. The predicted residual stresses are compared with those measured by neutron diffraction. The results show that dilution significantly influences the metallurgical and mechanical properties of weld metal (either as-deposited or reheated), and its consideration notably improves microstructure and residual stress predictions for a multi-pass steel weldment. For the weldment considered, an increase in dilution promotes the formation of martensite, enhances the hardness and leads to lower tensile stresses (or higher compressive stresses) in the weld metal. Such behaviour arises due to the higher hardenability of the base material, coupled with delayed austenite decomposition on cooling.

Steam Generator Grade P91 Steel Components Creep-Assessment By Test After Extended Service

2021 ◽  
Author(s):  
Ottaviano Grisolia ◽  
Lorenzo Scano ◽  
Francesco Piccini ◽  
Antonietta Lo Conte ◽  
Massimiliano De Agostinis ◽  
...  
Keyword(s):  
High Temperature ◽  
Weld Metal ◽  
Steam Generator ◽  
Microstructure Evolution ◽  
Creep Strength ◽  
Operation Temperature ◽  
Creep Analysis ◽  
Creep Cavitation ◽  
Weld Metal Microstructure ◽  
Metal Microstructure

Abstract Previous study carried out creep analysis for steam generator high-temperature-section two components, outflow tubing and manifold of the superheater harp: they may have been critical because of the long continued service (109,000 hours or twelve years) and loading conditions, including maximum operation temperature (565°C) and applied stress (65 MPa). Metallographic methods by replica had showed no evidence of the creep cavitation in all the positions considered for both tubing and manifold. In particular, they had not found any cavitation or phases affecting creep strength of the material in the base, HAZ and weld metal microstructure. Now, present study carries out investigation for the two components based on the next plant outage outcome, after further 20,000-hours service. Both metallographic methods and hardness measurements’ results would compare with previous ones providing microstructure evolution in the period.

Effect of Environment on Sn Whisker Growth during Welding of Electronic Wires

2015 ◽  
Vol 1110 ◽  
pp. 235-240 ◽  
Author(s):  
Tomomi Sakakida ◽  
Tatsuo Kubouchi ◽  
Yasuyuki Miyano ◽  
Mamoru Takahashi ◽  
Osamu Kamiya
Keyword(s):  
Energy Balance ◽  
Weld Metal ◽  
Whisker Growth ◽  
Weld Zone ◽  
Electrolytic Capacitor ◽  
Sn Whisker ◽  
Sn Whiskers ◽  
Weld Metal Microstructure ◽  
Short Circuits ◽  
Metal Microstructure

In Pb-free Al-Sn welding of electrolytic parts, single-crystal Sn whiskers easily form and can cause problems such as short circuits. Here we report that the growth of Sn whiskers in the weld zone of Al electrolytic condenser leads was suppressed in a vacuum environment. We examined the effect of the environment and weld metal microstructure in order to understand how to control and prevent whisker growth. In vacuum, the weld zone did not form whiskers after more than 100 h, whereas in air, whiskers grew within several hours. This suggests that whiskers require oxygen to form. The growth can be explained by the energy balance between the potential energy of the weld metal and the surface energy of the whisker. Our results will contribute to developing techniques for suppressing the formation of Sn whiskers during the percussion welding of Al electrolytic capacitor leads.

Influence of Thermal Aging on the Mechanical and Corrosion Properties of GTAW Welds of Alloy N06022

2002 ◽  
Vol 713 ◽  
Author(s):  
Tammy S. Edgecumbe Summers ◽  
Raúl B. Rebak ◽  
Todd A. Palmer ◽  
Paul Crook
Keyword(s):  
Volume Fraction ◽  
Charpy Impact ◽  
Corrosion Properties ◽  
Charpy Impact Toughness ◽  
Gas Tungsten Arc ◽  
Hydrochloric Acid Solutions ◽  
Tcp Phase ◽  
Mechanical And Corrosion Properties ◽  
Gas Tungsten Arc Welds ◽  
Kinetics Of

ABSTRACTThe phase stability of C-22 alloy (UNS N06022) gas tungsten arc welds was studied by aging samples at 593, 649, 704, and 760°C for times up to 6,000 hours. The tensile properties and the Charpy impact toughness of these samples were measured in the as-welded condition as well as after aging. The corrosion resistance was measured using standard immersion tests in acidic ferric sulfate (ASTM G 28 A) and 2.5% hydrochloric acid solutions at the boiling point. The microstructures of weld samples were examined using scanning electron microscopy (SEM). Precipitate volume fraction measurements were made using optical microscopy.Degradation of the mechanical and corrosion properties of C-22 welds due to aging at all temperatures investigated was seen to occur sooner than was seen in C-22 base metal. An evaluation of the kinetics of nucleation and growth of the precipitates forming at these temperatures, however, indicated that no significant changes in TCP phase morphology would occur at temperatures below approximately 300°C.a

scholarly journals Prediction of Dilution and Its Impact on the Metallurgical and Mechanical Behavior of a Multipass Steel Weldment

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Y. L. Sun ◽  
C. J. Hamelin ◽  
T. F. Flint ◽  
A. N. Vasileiou ◽  
J. A. Francis ◽  
...  
Keyword(s):  
Weld Metal ◽  
Mechanical Behavior ◽  
Arc Welding ◽  
Measurement Data ◽  
Base Material ◽  
Thermocouple Measurement ◽  
Cross Sectional ◽  
Steel Weldment ◽  
Gas Tungsten Arc ◽  
Compressive Stresses

Abstract A three-pass groove weld made by gas-tungsten arc welding in a 20-mm thick SA508 steel plate is modeled to predict the thermal, metallurgical, and mechanical behavior. The dilution for each pass is estimated as the proportion of base material in the weld metal, based on the predicted cross-sectional areas for the fusion zone (FZ) associated with each individual pass. The temperature predictions are consistent with the thermocouple measurement data and cross-weld macrographs. The predicted microstructures are qualitatively compared with the observed microstructures in cross-weld optical micrographs. The measured hardness is then used to quantitatively validate the predictions for postweld microconstituents (e.g., the ferrite, bainite, and martensite fractions), based on a hardness-microstructure correlation. The predicted residual stresses are compared with those measured by neutron diffraction. The results show that the dilution significantly affects the metallurgical and mechanical properties of weld metal (either as-deposited or reheated), and its consideration notably improves the predictions for microstructure and residual stress in the multipass steel weldment. Furthermore, the increase in dilution promotes the formation of martensite, which enhances the hardness, and leads to lower tensile stresses (or higher compressive stresses) in the weld metal. Such behavior arises due to the higher hardenability of the base material employed in this study, coupled with delayed austenite decomposition on cooling.

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