Research on Intergranular Corrosion Behavior of Welded Joints of Nuclear Grade Stainless Steel

2014 ◽  
Vol 809-810 ◽  
pp. 390-394
Author(s):  
Meng Yu Chai ◽  
Can Liang ◽  
Dong Dong Wang ◽  
Quan Duan ◽  
Zao Xiao Zhang
Keyword(s):  
Stainless Steel ◽  
Welded Joints ◽  
Heat Input ◽  
Intergranular Corrosion ◽  
Weld Zone ◽  
Base Material ◽  
Delta Ferrite ◽  
316Ln Stainless Steel ◽  
Welding Heat Input ◽  
Micro Structures

The intergranular corrosion (IGC) behaviors of welded joints of 316LN stainless steel with different welding heat input were investigated in this study. The boiling nitric acid method was chosen to provide the IGC environment. The corrosion rates of different specimens were studied and the micro-structures of each zone (base material, heat affected zone and weld zone) were analyzed in detail. The results show that welding heat input affects IGC resistance remarkably and low welding heat input can reduce the IGC tendency. The IGC test can be divided into three stages, i.e. the initial corrosion stage, stable corrosion stage and rapid corrosion stage. The IGC resistance of WZ for 316LN stainless steel is better than that of BM and HAZ due to the beneficial role of delta ferrite.

scholarly journals Corrosion Behavior of Welded Joints in Different Stainless Steels

2001 ◽  
Vol 71 (3) ◽  
pp. 440-449
Author(s):  
Eniko Reka Fabian ◽  
Janos Kuti ◽  
Jozsef Gati ◽  
Laszlo Toth
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Heat Affected Zone ◽  
Welding Speed ◽  
Welded Joints ◽  
Heat Input ◽  
Laser Power ◽  
Base Material

The welded metals characteristics produced by TIG welding or laser beam welding depend on heat input as a function of laser power and welding speed. High laser power and high welding speed have produced welded joint with a remarkable decrease in fusion zone size and an acceptable weld profile with high weld depth/width ratio. At duplex stainless steels the microstructure of welded metal, and heat affected zone is strongly influenced by cooling rate, which is depend on heat input as a function of laser power and/or welding speed. It was found that increasing welding speed the corrosion rate of welded joints decreased. In austenitic stainless steels appeared pitting corrosion in the base material as well as in the welding zone. In case of 2304 duplex stainless steel pitting corrosion appeared in welded metal and heat affected zone in case of autogenously welding, but at 2404 duplex stainless steel pitting appear more in the heat affected zone.

Influence of Heat Input on Grain Size in the Structure of 316LN Stainless Steel Welded Joints

2014 ◽  
Vol 1033-1034 ◽  
pp. 834-838 ◽  
Author(s):  
Li Chan Li ◽  
Can Liang ◽  
Dong Dong Wang ◽  
Yong Quan Li ◽  
Quan Duan
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Welded Joints ◽  
Heat Input ◽  
Arc Welding ◽  
Great Influence ◽  
Shielded Metal Arc Welding ◽  
316Ln Stainless Steel ◽  
Metal Arc Welding ◽  
Δ Ferrite

316LN stainless steel is a material with excellent mechanical properties, good resistance to intergranular corrosion and good weldability, and it has been used in many fields of industry. Welding quality has great influence on the strength and corrosion resistance of weldment. In this study, one group of submerged arc welding and three groups of shielded metal arc welding were taken to study the influence of heat input on grain size in the structure of 316LN welded joints. The results show that the microstructures of the weld zones in experiment were all consist of austenite and a small amount of banding or dendritic δ-ferrite and the amount of ferrite decrease with the increase of heat input. It also can be concluded from the experiment that with the increase of welding heat input the grain size of overheated zone decrease.

scholarly journals Investigation on Impact of Heat Input on Microstructural, Mechanical, and Intergranular Corrosion Properties of Gas Tungsten Arc-Welded Ti-Stabilized 439 Ferritic Stainless Steel

2021 ◽  
Author(s):  
Santosh K. Gupta ◽  
Awanikumar P. Patil ◽  
Ramesh C. Rathod ◽  
Vipin Tandon ◽  
Himanshu Vashishtha
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Heat Input ◽  
Intergranular Corrosion ◽  
Weld Zone ◽  
High Heat ◽  
Electron Backscattered Diffraction ◽  
Corrosion Properties ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

AbstractIn the present study, gas tungsten arc welding was employed to weld Ti-stabilized 439 ferritic stainless steel using 308L austenitic stainless steel filler electrode with varying heat input, i.e., low heat input (LHI) and high heat input (HHI). The optical microstructure revealed the formation of retained austenite (RA) and ferrite in the weld zone (WZ), whereas the peppery structure consisting of chromium-rich carbides were observed in the heat-affected zone for both the weldments. The volumetric fraction of RA was calculated using X-ray diffraction analysis. The RA’s content decreased, whereas grain size in WZ increased with an increase in heat input. The local misorientation and grain boundary distribution in the welded region was investigated by electron backscattered diffraction. The LHI weldment depicted the higher micro-hardness and tensile strength attributed to the higher content of RA as compared to HHI; however, the opposite trend was observed for the intergranular corrosion resistance.

scholarly journals A Study on the Fiber YAG Laser Welding of 304L Stainless Steel

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2022
Author(s):  
Essam R. I. Mahmoud ◽  
Hamad Almohamadi ◽  
Abdulrahman Aljabri ◽  
Mohamed Abdelghany Elkotb
Keyword(s):  
Stainless Steel ◽  
Fracture Strength ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Heat Input ◽  
Laser Power ◽  
Processing Parameters ◽  
304L Stainless Steel ◽  
Delta Ferrite ◽  
Full Penetration

This work aims to optimize the main YAG fiber laser parameters to weld 304L stainless steel plates of 3 mm thick. Different laser powers (2500, 2000, and 1500 W) and speeds (60, 40, and 20 mm/s) were used and merged in heat input, maintaining the defocusing distance at –2 mm to get full penetration. The weld quality and the effect of the laser heat input on the microstructures of the weld and heat-affected zones were investigated. Besides, the fracture strength of the welded joints and hardness distribution through the cross-sections were evaluated. The weld width has a direct relationship with heat input. The laser power of 2800 W produced full penetration joints without any macro defects while reduction in laser power pronounced partial penetration defects. The size of the heat-affected zone in all the processing parameters was very small. The microstructure of the weld zone shows columnar dendrite austenite grains with small arm spacing in most of the welded zone. The size of the dendrites became finer at lower heat input. At a higher heat input, a reasonable amount of lathy equiaxed grains with some delta ferrite occurred. A small amount of delta ferrite was detected in the heat-affected zone, which prevented the crack formation. The hardness of the weld metal was much higher than that of the base metal in all processing parameters and it has a reverse relationship with the heat input. The fracture strength of the welded joints was very close to that of the base metal in the defect-free samples and it increased with decreasing the heat input.

Shielded metal arc welding of AISI 409M ferritic stainless steel: study on mechanical, intergranular corrosion properties and microstructure analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sachin Ambade ◽  
Chetan Tembhurkar ◽  
Awanikumar P. Patil ◽  
Prakash Pantawane ◽  
Ravi Pratap Singh
Keyword(s):  
Corrosion Behavior ◽  
Heat Input ◽  
Intergranular Corrosion ◽  
Arc Welding ◽  
High Heat ◽  
Shielded Metal Arc Welding ◽  
Corrosion Properties ◽  
Content Type ◽  
Welding Heat Input ◽  
Metal Arc Welding

Purpose The purpose of this study is on AISI 409 M ferritic stainless steel (FSS) which is developing a preferred choice for railway carriages, storage tanks and reactors in chemical plants. The intergranular corrosion behavior of welded SS 409 M has been studied in H2SO4 solution (0.5 M) with the addition of NH4SCN (0.01 M) with different heat input. As this study is very important in context of various chemical and petrochemical industries. Design/methodology/approach The microstructure, mechanical properties and intergranular corrosion properties of AISI 409 M FSS using shielded metal arc welding were investigated. Shielded metal arc welding with different welding current values are used to change the heat input in the joints resulted in the microstructural variations. The microstructure of the welded steel was carefully inspected along the width of the heat-affected zone (HAZ) and the transverse-section of the thin plate. Findings The width of heat affected zone (3.1,4.2 and 5.8 mm) increases on increasing the welding heat input. Due to change in grain size (grain coarsening) as HAZ increased. From the microstructure, it was observed that the large grain growth which is dendritic and the structure become finer to increase in welding heat input. For lower heat input, the maximum microhardness value (388HV) was observed compared with medium (351 HV) and higher heat input (344 HV), which is caused by a rapid cooling rate and the depleted area of chromium (Cr) and nickel (Ni). The increase in weld heat input decreases tensile strength, i.e. 465 MPa, 440 MPa and 418 MPa for low, medium and high heat input, respectively. This is because of grain coarsening and chromium carbide precipitation in sensitized zone and wider HAZ. The degree of sensitization increases (27.04%, 31.86% and 36.08%) to increase welding heat input because of chromium carbide deposition at the grain boundaries. The results revealed that the higher degree of sensitization and the difference in intergranular corrosion behavior under high heat input are related to the grain growth in the HAZ and the weld zone. Originality/value The study is based on intergranular corrosion behavior of welded SS 409 M in H2SO4 solution (0.5 M) with the addition of NH4SCN (0.01 M) with different heat input which is rarely found in literature.

Effect of Cold Rolling on Sensitization of 304 Stainless Steel Weldments

2013 ◽  
Vol 856 ◽  
pp. 60-63
Author(s):  
M. Milad ◽  
N. Zreiba
Keyword(s):  
Stainless Steel ◽  
Heat Input ◽  
Cold Work ◽  
304 Stainless Steel ◽  
Optimum Level ◽  
Microstructural Investigation ◽  
Welding Heat Input ◽  
Degree Of Sensitization ◽  
Electrochemical Potentiokinetic Reactivation ◽  
Cold Rolled

The sensitization of stainless steel type AISI304 (304SS) is evaluated as a function of pre-welding cold work and welding heat input. 304SS is cold rolled to various percentages of thickness reduction of up to 50% at ambient temperature before being TIG welded. The susceptibility of 304SS to sensitization (weld decay) is evaluated using ASTM A262, practice A and electrochemical potentiokinetic reactivation tests. The results indicate that the influence of pre-welding cold work on the degree of sensitization (DOS) is distinct and appreciable within the range of 10% to 35% CR. In addition, within this range the optimum level of cold work after which the DOS starts to decrease is found to be inversely related to the amount of welding heat input. At higher levels of cold work of ≥ 35% CR, it is found that neither the cold work nor the heat input significantly influences the amount of DOS. Microstructural investigation showed that the predominant intergranular corrosion (IGC) occurs at austenite grain boundaries and less likely at ferrite / austenite interfaces of the weld metal. Meanwhile, transgranular attack at austenite bulk matrix along the defects is rarely observed.

scholarly journals Application of electrochemical methods for the investigation of intergranular corrosion welded joint austenitic stainless steel 19Cr-9Ni

2011 ◽  
Vol 65 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Bore Jegdic ◽  
Ana Alil ◽  
Zlatan Milutinovic ◽  
Zoran Odanovic ◽  
Bojan Gligorijevic ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Welded Joints ◽  
Intergranular Corrosion ◽  
Significant Degree ◽  
Electrochemical Methods ◽  
Double Loop ◽  
Quantitative Evidence ◽  
Degree Of Sensitization ◽  
Electrochemical Potentiokinetic Reactivation

Sensitization degree of the austenitic stainless steel welded joints was investigated by electrochemical methods of the double loop electrochemical potentiokinetic reactivation (DL EPR) in H2SO4 + KSCN solution, and by the measurement of corrosion potential of the steel in the drop of the solution of HNO3 + FeCl3 + HCl. The welded joints were tested by X-ray radiographic method in order to check the presence of the weld defects. Grain size of the base metal and the welded joints were determined by optical microscopy. Good agreement between the results obtained by different electrochemical methods was obtained. Heat-affected zone (HAZ) of the austenitic stainless steel welded joints has shown significant degree of sensitization. The double loop electrochemical potentiokinetic method gave quantitative evidence about susceptibility of the stainless steel to intergranular corrosion.

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