Investigations on Design and Formulation of Buttering Layer Electrode Coatings for Bimetallic Welds

2016 ◽  
Vol 880 ◽  
pp. 37-40 ◽  
Author(s):  
Deepak Bhandari ◽  
Rahul Chhibber ◽  
Navneet Arora ◽  
Rajeev Mehta

The bimetallic welds (BMWs) between ferritic low alloy steels and austenitic stainless steel are used widely in steam generators of the power plants. The adoption of these welds in wide industrial applications provides feasible solutions for the flexible design of the products by using each material efficiently and economically. The present paper is an effort towards studying the development of austenitic stainless steel buttering filler material for bimetallic weld joint. The work aims at the design and development of buttering layer electrode coatings for shielded metal arc welding process using extreme vertices design methodology suggested by McLean and Anderson to study the effect of electrode coating ingredients on the buttering layer metal composition and delta ferrite content to prevent solidification cracking.

Otopro ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 18
Author(s):  
Nidia Lestari

Austenitic stainless steel or commonly known as AISI 304 stainless steel has advantages, including good ductility at relatively low temperatures and high resistance to corrosion. These properties make Austenitic Stainless Steel a candidate material for use in pipe fabrication systems, automotive exhaust gas systems and some equipment related to the chemical and nuclear industry. Therefore, it is necessary to analyze the variation of welding currents on the strength of the welds in the application of Shielded Metal Arc Welding (SMAW) on stainless steel. The electrodes used are E308-16 types with current variations of 90 amperes, 100 amperes and 110 amperes. The results showed that the electric current factor in the SMAW welding process greatly influenced the welding results in terms of its strength. The highest mechanical strength was obtained at welding current of 110 Ampere, with a heat input of 976.067 J / mm, an average mechanical strength of 68.438 kg / mm2 for tensile stress and strain of 47.451% in the tensile test, and an average value of hardness of 225.008 HV for hardness test in weld.


Author(s):  
Deepak Bhandari ◽  
Rahul Chhibber ◽  
Lochan Sharma ◽  
Navneet Arora ◽  
Rajeev Mehta

The bimetallic welds are frequently utilized for pipeline transport system of the nuclear power plants. The occurrences of welding defects generally depend on the filler electrode as well as the electrode coatings during shielded metal arc welding process. This study involves the design of austenitic stainless steel welding electrodes for SS304L–SA516 bimetallic welds. The objective of research work includes the novel design of Al2O3–TiO2–CaO–SiO2 coatings by combining two ternary phase systems using extreme vertices mixture design methodology to analyze the effect of key coating constituents on the weld metal chemistry and mechanical properties of the welds. The significant effect of electrode coating constituent CaO on weld metal manganese content is observed which further improves the toughness of bimetallic weld joints. Various regression models have been developed for the weld responses and multi objective optimisation approach using composite desirability function has been adopted for identifying the optimized set of electrode coating compositions. The role of delta ferrite content in promoting the favourable solidification mode has been studied through microstructural examination.


Author(s):  
Waris N Khan ◽  
Rahul Chhibber

This work investigates the microstructure and mechanical properties of 2507 super duplex stainless steel and API X70 high strength low alloy steel weld joint. This joint finds application in offshore hydrocarbon drilling riser and oil–gas pipelines. Coated shielded metal arc welding electrodes have been designed and extruded on 309L filler and their performance compared with a commercial austenitic electrode E309L. Filler 309L solidifies in ferrite-austenite (F-A) mode with a resultant microstructure comprising skeletal ferrites with austenite distributed in the interdendritic region. Results of tensile and impact tests indicate that weld fabricated with laboratory-developed electrodes has higher ductility and impact energy than the commercial electrode. The tensile strength and weld hardness of commercial electrodes are superior. The laboratory-made electrode’s microhardness is lower than the commercial electrodes, making the former less prone to failure. An alternative welding electrode coating composition has been suggested through this work and found to be performing satisfactorily and comparable to the commercially available electrodes.


Author(s):  
Haiyang Qian ◽  
David Harris ◽  
Timothy J. Griesbach

Thermal embrittlement of cast austenitic stainless steel piping is of growing concern as nuclear power plants age. The difficulty of inspecting these components adds to the concerns regarding their reliability, and an added concern is the presence of known defects introduced during the casting fabrication process. The possible presence of defects and difficulty of inspection complicate the development of programs to manage the risk contributed by these embrittled components. Much work has been done in the past to characterize changes in tensile properties and fracture toughness as functions of time, temperature, composition, and delta ferrite content, but this work has shown a great deal of scatter in relationships between the important variables. The scatter in material correlations, difficulty of inspection and presence of initial defects calls for a probabilistic approach to the problem. The purpose of this study is to describe a probabilistic fracture mechanics analysis of the maximum allowable flaw sizes in cast austenitic stainless steel piping in commercial power reactors. Attention is focused on fully embrittled CF8M material, and the probability of failure for a given crack size, load and composition is predicted considering scatter in tensile properties and fracture toughness (fracture toughness is expressed as a crack growth resistance relation in terms of J-Δa). Random loads can also be included in the analysis, with results generated by Monte Carlo simulation. This paper presents preliminary results for CF8M to demonstrate the sensitivity of key input variables. The outcome of this study is the flaw sizes (length and depth) that will fail with a given probability when a given load is applied.


2017 ◽  
Vol 750 ◽  
pp. 26-33
Author(s):  
Alaa Abu Harb ◽  
Ion Ciuca ◽  
Robert Ciocoiu ◽  
Mihai Vasile ◽  
Adrian Bibis ◽  
...  

The welding technique used for ASIS 304 and 316L austenitic stainless steel sheets both with a thickness of 3mm is gas tungsten arc welding (TIG) and manual metal arc welding (MMAW). Mechanical properties that were verified include: hardness test and tensile test before welding and after it. The welding process was done on two types of specimens: with a central hole and without hole. We concluded that there was a decrease in the properties of tensile for both specimens with central hole, and 316L had tensile characteristics better than 304 when using the technique TIG. As for 304, it had tensile characteristics better than 316L when using the technique MMAW. We also concluded that the existence of central holes had an influence on the hardness characteristics on both types. The hardness increased in 304 but decreased in 316L. The welding process also showed that there was no influence of MMAW on hardness on both specimens. However it showed that there was no influence of TIG on the hardness for 304, but for 316L values increased.


2020 ◽  
Vol 299 ◽  
pp. 908-913 ◽  
Author(s):  
Hussam L. Alwan ◽  
Yury S. Korobov ◽  
N.N. Soboleva ◽  
N.V. Lezhnin ◽  
A.V. Makarov ◽  
...  

The ultrasonic vibratory test was carried out to evaluate the cavitation erosion/corrosion resistance of welded-deposited austenitic stainless steel/E308L-17. Three layers of the E308L-17 electrode were deposited onto AISI 1040 substrate utilizing Shielded Metal Arc Welding (SMAW) process. The eroded surfaces of the E308L welded deposit/coating and AISI 1040 substrate steel have been analyzed by evaluating surface topography, as well as scanning electron microscope (SEM) micrographs. In addition, the cumulative weight loss and erosion rate curves were attained to evaluate the cavitation resistance of the tested materials. The cavitation results showed that the E308L-17 deposited stainless steel has lost about 15 mg as a cumulative weight, while the loss of AISI 1040 substrate was about 123 mg. This is equal to 0.12% and 1.0% of the original test specimen weight for the E308L-17 and AISI 1040, respectively. Consequently, E308L-17 austenitic stainless steel can be effectively used as a protective material for surfaces exposed to cavitation wear, since the AISI 1040 substrate has been enhanced by 8 times using E308L stainless steel.


2013 ◽  
Vol 331 ◽  
pp. 578-582 ◽  
Author(s):  
Li Chan Li ◽  
Meng Yu Chai ◽  
Yong Quan Li ◽  
Wen Jie Bai ◽  
Quan Duan

Influences of heat input on the microstructure and grain size of shielded metal arc welded 316L stainless steel joints were studied. Three heat input combinations were selected from the operating window of the shielded metal arc welding process and welded joints made using these combinations were subjected to microstructural evaluations so as to analyze the effect of thermal arc energy on the microstructure and grain size of these joints. The results of this investigation indicate that the microstructure of the weld zone and the fusion zone are austenite and a small amount of ferrite while the microstructure of the heat affected zone (HAZ) are austenite and a small amount of MC type carbides, and it can be seen that the amount of ferrite in the weld zone decreases with heat input. For the joints investigated in this study, the average grain size in the HAZ increases with heat input.


2018 ◽  
Vol 18 ◽  
pp. 7-13
Author(s):  
Brahim Belkessa ◽  
Djamel Miroud ◽  
Billel Cheniti ◽  
Naima Ouali ◽  
Maamar Hakem ◽  
...  

This work purposes to investigate the microstructure and the mechanical behavior of dissimilar metals weld between 2205 duplex stainless steel (UNS 31803) and high strength low alloy steel API X52. The joining was produced by shielded metal arc welding process using two different filler metals, the duplex E2209 and austenitic E309 grade.The microstructures of the dissimilar welded joints have been investigated by optical microscopy, scanning electron microscopy and energy-dispersive spectroscopy (EDS). The EDS analysis performed at the API X52/weld metal interface showed an evident gradient of Cr and Ni between fusion and type II boundaries, where the highest hardness value was recorded.


Author(s):  
Haiyang Qian ◽  
David Harris ◽  
Timothy J. Griesbach

The concern of toughness reduction due to thermal embrittlement of cast austenitic stainless steel (CASS) piping is increasing as nuclear power plants age. Because of the large and variable grain size of the CASS materials, the ultrasonic inspection (UT) difficulties of the CASS components increases concerns regarding their reliability. Another added concern is the presence of potential defects introduced during the casting fabrication process. The possible presence of defects and difficulty of inspection complicate the development of programs to manage the risk contributed by these potentially degraded components. Experiments have been performed in the past to evaluate the effect of thermal embrittlement on tensile properties and fracture toughness as functions of time, temperature, composition, and delta ferrite content, but considerable scatter has been shown in the results among the important variables. A probabilistic approach is proposed for the evaluation of the aging effect based on the scatter in material correlations, difficulty of inspection and presence of initial defects. The purpose of this study is to describe a probabilistic fracture mechanics analysis approach for the determination of the maximum allowable flaw sizes in CASS piping components in commercial power reactors, using Monte Carlo simulation. Attention is focused on fully embrittled CF8M material, and the probability of failure for a given crack size, load and composition is predicted considering scatter in tensile properties and fracture toughness (fracture toughness is expressed as a crack growth resistance relation in terms of J-Δa). The correlation between the reduced toughness and increased tensile properties due to thermal embrittlement is also included in the analysis. This paper presents results for CF8M to demonstrate the sensitivity of key input variables on the most severely embrittled material. The output of this study is the flaw size (length and depth) that will fail with a given probability as a function of load and geometry.


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