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.

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.

scholarly journals On the Intergranular Corrosion Properties of Thin Ferritic Stainless Steel Sheets Welded by Fiber-Laser

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1088
Author(s):  
Niklas Sommer ◽  
Igor Kryukov ◽  
Christian Wolf ◽  
Michael Wiegand ◽  
Martin Kahlmeyer ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Fiber Laser ◽  
Ferritic Stainless Steel ◽  
Intergranular Corrosion ◽  
Tensile Tests ◽  
Butt Joint ◽  
Thin Sheets ◽  
Corrosion Properties ◽  
Steel Sheets ◽  
Ct Analysis

In the present investigation, thin sheets of stabilized and unstabilized ferritic stainless steel were welded in butt joint configuration using irradiation of a 1070 nm fiber-laser. Using optical microscopy, the microstructural evolution upon alternating heat input was characterized. In addition to that, hardness and tensile tests were carried out on the specimens. Detailed focus was given to the intergranular corrosion properties, which were investigated on basis of the Strauss test with different times of exposure to the corrosive environment. Following these tests, the mechanical properties of the joints were characterized using tensile tests. A combination of the latter with an inspection by μ-CT analysis allows for the proposition of an intergranular corrosion rate with regard to the degradation of the joint strength.

Qualification of Laser Welded High Performance S44660 Ferritic Stainless Steel for Condenser Tube Applications

2003 ◽  
Author(s):  
James D. Fritz ◽  
Curtis W. Kovach
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
High Performance ◽  
Sheet Material ◽  
Cooling Water ◽  
Welding Process ◽  
Gas Tungsten Arc ◽  
Critical Pitting Temperature ◽  
Gas Tungsten ◽  
Welding Processes

The laser tube welding process has for the first time been used to produce power plant steam condenser tubing in the high performance ferritic stainless steel grade UNS S44660. This material has traditionally been produced as welded tubing by the gas tungsten-arc welding process for use in seawater and other severe cooling water environments. To verify the corrosion resistance of this new product, corrosion tests have been conducted on production tubing to compare the traditional and new welding processes. The acidified ferric chloride test was used for evaluation because it is a meaningful aggressive test capable of measuring resistance to localized pitting corrosion, the most common potential failure mode for stainless steels used in cooling water environments. Pitting tests conducted over a range of temperatures produced a critical pitting temperature of 65°C for laser welded-annealed tube. This critical pitting temperature was demonstrated to be equal to that of as-produced S44660 sheet material or that of gas tungsten-arc produced tubing. The tubing met all other metallurgical and mechanical property quality requirements. When pitting did occur it exhibited no preference for initiation at welds. Thus, laser welded. high performance stainless condenser tubing should be fully capable of providing good performance in severe cooling water environments.

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