Corrosion Resistance of TIG Welded Joints of Stainless Steels

American Journal of Scientific and Industrial Research, 2012

The aim of this work is to study the influence of the joint design of Tungsten Inert Gas welding (TIG) on the corrosion resistance of low carbon steel (type St-37). A single V-butt joints of a low carbon steel plates are performed by the V-angles 30°,45°,60° and square butt joint (angle 90°). Corrosion behavior of welded specimens in 3.5% NaCl solution was examined using Tafel polarization measurements. The corrosion behavior of the welded joint also is determined by open circuit potential (OCP) after that the cell's current is changed due to increasing in potential by ±100. The results shown that the corrosion rate of welded joint with V-angle of 30° was found to be less than that of other angles (45°,60° and 90°). It found that the corrosion resistance of base metal was better than that of all welded joints. From the results of the microstructure it is evident that the joint design or geometric shape of weld has an important role in the welding process, when the preparation angle value of the weld gets bigger, the faults gets less due to increase of heat quantity in the weld region.

International Journal for Research in Applied Science and Engineering Technology (IJRASET) i, 2021

Now days, most of the structural fabrications possess welded joints that are produced using suitable welding technique. However, the joining of thick plates in a single pass welding is a cumbersome task to many fabricators. Likewise, the selection of welding technique, filler wire and welding condition for the similar and dissimilar welding of several metals is at the development stage. The similar and dissimilar metal joints of have been emerged as a structural material for various industrial applications which provides good combination of mechanical properties like strength, corrosion resistance with lower cost. Selections of joining process for such a material are difficult because of their physical and chemical properties. The stainless steel of similar and dissimilar material joints are very common structural applications joining of stainless steel is very critical because of carbon precipitation and loss of chromium leads to increase in porosity affects the quality of joint leads deteriorate strength. In the present study, stainless steel of grades 310 and 316 were welded by Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG) welding with compound flux of 50 % SiO 2 + 50 % TiO 2 processes. The mechanical behavior like hardness, tensile strength and bending properties of similar and dissimilar metal joints were investigated.

Uluslararası Muhendislik Arastirma ve Gelistirme Dergisi, 2020

304L austenitic and 420 martensitic stainless steels are demanded in wide range of industries. 304L alloy exhibits good resistance to oxidizing medias up to 760°C and they also maintain superior impact properties at cryogenic temperatures while 420 alloy provides the strength values close to tool steels in with satisfactory corrosion properties in ambient atmospheres. In this work; 420 plate is TIG (Tungsten Inert Gas) welded with 304L plate with both thicknesses of 3 mm. Welding operation is applied by two passes under pure argon gas also with shielding the weld root. 3 types of TIG welding rods; ER312, ER316L and ER2209 are used in TIG welding for ensuring 3 different weld metal compositions. The effects of TIG welding rod type on weld metal phase ratios with microstructural and corrosion properties are investigated. Microstructural inspections and corrosion (weight loss) tests are applied to all joints after welding operations. The sample joined by ER312 TIG rod transformed the weld metal into dendritic microstructure and the sample joined by ER2209 TIG rod resulted in globular type of weld metal microstructure. The specimen that welded by ER316L type TIG welding rod resulted in the best corrosion test values among all welded samples.

316L stainless steel (SS) is one of the most consumable materials in orthopedic implants. Certain types of orthopedic implants such as monobloc hip stems are often made of two elements welded together. In this study, effect of TIG welding on corrosion behavior of 316L stainless steel in physiological solution was investigated. In this method, filler metal wasn't used due to the small thickness of samples and it was welded to lap form. Corrosion behavior in physiological solution at 37 °C was investigated with potentiodynamic polarization curves. Microstructure of base metal (BM) and weld metal (WM) was studied with scanning electronic microscopy (SEM). The corrosion behavior of weld metal, base metal and couple (BM and WM together) was compared together. For detecting microstructure and phases in BM and WM, X-ray diffraction analysis was done. Finally, post-weld heat treatment (PWHT) was performed on as-welded samples. Results indicated that corrosion behavior of WM was better than the BM. This phenomenon was attributed to secondary phases that were present in the BM. Secondary phases in the weld metal are dissolved when the base metal is melting due to the welding process. Based on the results of electrochemical analysis, it was determined that the corrosion rate of a couple was more than of other parts. Heat affected zone (HAZ) is responsible for this phenomenon. The adjacent zones of the weld metal are classically less corrosion resistant, thereby being attacked preferentially when the steel is exposed to corrosive environments. PWHT decreased the corrosion rate of the couple.

Periodica Polytechnica Mechanical Engineering, 2022

Electricity produced in power plants is essential in our everyday life. In general, the energy transfer takes place after processing the energy source in boilers or steam generators. Steam is generated through this process, that operates the turbines and they generate electricity through the generators. As such equipment operates in a high pressure, corrosive and high temperature environment, these circumstances may damage the tubes in the heat exchangers. Our research examines the potential of corrosion of heat exchanger tubes after welding. The typical corrosion process is pitting. The corrosion resistance of stainless steel depends on a protective, passive film formed on the surface of the steel exposed to the service environment. The use of fusion welding for fabrication leads to local variations in the chemical composition inside the material, which may significantly alter the stability of the passive layer and hence the corrosion behavior. The impact of welding parameters (shi...

Welding International, 2016

The AISI 444 stainless steel (SS) has become an option to substitute the AISI 316L SS because of its low cost and satisfactory corrosion resistance. However, the use of AISI 444 alloy tubes in heat exchangers causes the welding of a dissimilar joint. The aim of this study was evaluate the corrosion resistance of the tube-to-tubesheet welded by a TIG process composed of AISI 316L and AISI 444. Preparation of samples was executed through replication of tube-totubesheet joints. In order to test the corrosion resistance of the welded joint, the following tests were applied: sensitisation, mass loss from room temperature up to 90 °C and electrochemical corrosion tests in 0.5 mol/L HCl and 0.5 mol/L H 2 SO 4 electrolytes. The results have shown that the dissimilar joint suffers galvanic corrosion with increased degradation of the heat-affected zone of the AISI 444 tube. Nevertheless, the mechanisms of localised corrosion (pit and intergranular) were more active in the AISI 316L alloy. It is concluded that the dissimilar joint showed better corrosion resistance than the welded joint composed solely of AISI 316L at temperatures up to 70 °C, as the conditions observed in this work.

Archives of Metallurgy and Materials, 2016

This paper presents results of pitting corrosion resistance of TIG (autogenous and with filler metal) and A-TIG welded lean duplex stainless steel S82441/1.4662 evaluated according to ASTM G48 method, where autogenous TIG welding process was applied using different amounts of heat input and shielding gases like pure Ar and Ar+N2 and Ar+He mixtures. The results of pitting corrosion resistance of the welded joints of lean duplex stainless steel S82441 were studied in as weld conditions and after different mechanical surface finish treatments. The results of the critical pitting temperature (CPT) determined according to ASTM G48 at temperatures of 15, 25 and 35°C were presented. Three different surface treatment after welding were applied: etching, milling, brushing + etching. The influence of post weld surface treatment was studied in respect to the pitting corrosion resistance, basing on CPT temperature.Research on TIG welding of lean duplex stainless steel S82441/1.4662 showed a cle...

2018

Corrosion behavior of three zones in 316L austenitic stainless-steel weld joints (base material BM, heat affected zone HAZ and weld metal WM) was studied in saline solution (5% NaCl) at room temperature. According to the potentiodynamic polarization and the scanning electron microscopy (SEM), some microstructure variation in the BM and HAZ were found. By comparison between the L316L, LTIGF316L and LTIGV316L specimen, the presence of fatigue fracture in the BM for welded specimens was observed. Topography analysis has evidenced differences in the pits dimensions and shape for each specimen.

Metals

Stainless steels and mild steels are widespread materials in several industries. The dissimilar welding of materials is a technique used to meet the needs of various industries. Mild steel and 316L austenitic stainless steel have different chemical compositions and thermal and mechanical properties. Therefore, it would be interesting to develop a flux paste that would ensure the reliability and sustainability of welded structures made of dissimilar materials. In this work, pseudo-component fluxes were analyzed regarding the resulting weld aspects, microstructures, mechanical properties and corrosion resistance of dissimilar 316L austenitic stainless steel and mild steel welded joints. Using a mixing design available in Minitab 17 software, the obtained optimal pseudo-component flux was composed of 74% SiO2, 3% Fe2O3, 13% Cr2O3 and 10% NaF. During this investigation, the weld carried out using the optimal flux combination with the activated tungsten inert gas (ATIG) technique was eva...

INTERNATIONAL JOURNAL OF RECENT TRENDS IN ENGINEERING & RESEARCH, 2020

The aim of this work is to study the mechanical properties that affect the welding joint of metals. Stainless Steel 304 was welded to Mild steel using a TIG welding which also known as Gas tungsten arc welding (GTAW) or tungsten inert gas (TIG) welding The weld area and electrode is protected from oxidation and other atmospheric contamination is prevented by an inert shielding gas (argon or helium). Metals welding have great scope in advanced technology that includes high hardness, high strength and corrosion resistance properties. The combination of stainless steel has got large number of application in industry such as nuclear plant, and heat exchanger assembly etc. Due to the fact that low cost of mild steel and corrosion resistance property of stainless steel, all these application requires welding of the two which can perform the desired service requirement of the industry. The results indicate the optimum value of current and voltage which will be applied to developed to maximize the mechanical properties of welding the stainless steel 306 and Mild steel.