Dissimilar Stainless Steel Research Articles

Phase transformation effect on residual stress development in fusion welding of dissimilar stainless steels with different thickness

Phase transformation effect on residual stress development in fusion welding of dissimilar stainless steels with different thickness

Multi-material stainless steel fabrication using plasma wire arc additive manufacturing

Layered stainless steel samples were manufactured using Plasma Wire Arc Additive Manufacturing by depositing alternating layers of two dissimilar stainless steels onto an AISI 316L substrate. The selected materials were the M430 ferritic and M316L austenitic stainless steels. Comprehensive microstructural characterization in different areas, including interfaces between the two different materials, was achieved through optical microscopy and electron backscatter diffraction. Results revealed good weldability among the two-layered steels and on the substrate. Also, a gradient duplex structure was observed mainly at the layer interfaces, suggesting a nuanced blending of properties in the deposited zone. To establish a direct correlation with mechanical properties in the observed structures, macro and micro-hardness tests were conducted along the cross-section. These tests evidenced the presence of a harder phase along the interface compared to the individual materials. The microstructural analysis corroborated the presence of mixing between phases in conjunction with some areas of delta ferrite.

Optimization of mechanical and surface properties of friction stir welded dissimilar joint of 2507 SDSS and 317L ASS by controlling process parameters

Stainless steel welding has been widely used in industrial manufacturing, and friction stir welding has been recognized to reduce production costs significantly. To fully utilize the different properties of 2507 super duplex stainless steel (SDSS) and 317L austenitic stainless steel (ASS), the mechanical and surface properties of 2507 SDSS and 317L ASS dissimilar stainless steel joints were improved using the friction stir welding (FSW) method. The influence of rotation speed on the microstructural characteristics, mechanical properties, and corrosion behavior of the weld joints was investigated by welding at a constant speed of 20 mm/min within the range of 300–600 rpm. Specifically, at 400 rpm, a welded joint with optimal performance was obtained. When the rotation speed is 400 rpm, the yield strength (YS) and ultimate tensile strength (UTS) of the welding joint are 493 and 692 MPa, respectively, and the elongation (EL) is 32 %. The tensile strength is higher than 317L ASS but lower than 2507 SDSS, the EL is lower than those of 317L ASS and 2507 SDSS, and the friction coefficient of the welded joint is 0.93, which is between 317L ASS and 2507 SDSS. Notably, the refinement of grains in the stirred zone significantly improved the corrosion resistance of the welded joint, considerably exceeding that of the 317L ASS but still lower than the 2507 SDSS. This work can provide a process reference for studying the mechanical and corrosion properties of dissimilar stainless steel FSW.

Examination on joining of 2 mm thick dissimilar stainless steel plates using resistance spot welding

In the present study, dissimilar metals such as austenitic stainless steel (ASS) and duplex stainless steel (DSS) with a thickness of 2 mm are joined by resistance spot welding process to investigate the welding metallurgy and failure behavior under different heat inputs. Non-uniform electrode impressions are observed on ASS and DSS sides due to their different thermal conductivity and electrical resistivity. The microstructure of the Fusion Zone (FZ) shows that higher heat input accelerates the growth of Intra Granular Austenite (IGA) due to faster cooling. Scanning electron microscopy (SEM) - Energy Dispersive x-ray (EDX) investigation at FZ showed that Chromium & Molybdenum decrease with increasing heat input due to a decrease in ferrite content. X-ray diffraction analysis confirmed that ferrite formation is limited at higher heat input. Microhardness study revealed that the higher hardness is in the middle of the weld nugget, which is due to the presence of equiaxed grains and IGA. The lowest hardness on the ASS side of Heat Affected Zone (HAZ) is due to the phenomenon of grain growth, and the HAZ DSS side has a higher hardness than DSS Base Metal (BM) due to the mechanism of solid solution strengthening. The tensile shear test showed that the tensile shear strength increases with the addition of heat. SEM Examination of the fracture surface revealed the presence of an equiaxed dimple structure on the ASS side, confirming ductile fracture, and torn bonds on the DSS side, confirming quasi-gap fracture due to the work-hardening ability of both plates. This study is carried out to understand the relationship between mechanical, metallurgical, and failure behaviours, because, researches on joining of dissimilar (AISI 316 L and DSS 2205) stainless steel sheets using Resistance Spot Welding process is very limited and need to be studied in detail.

Weldability of dissimilar stainless steels by MIG welding with different gas combinations

Weldability of dissimilar stainless steels by MIG welding with different gas combinations

Influence of shielding gas on machining and wear aspects of AISI 310–AISI 2205 dissimilar stainless steel joints

Abstract In this article, the effect of shielding gas combinations on gas tungsten arc-welded dissimilar AISI 310 steel and AISI 2205 steel joints was investigated. Two gases such as nitrogen and carbon dioxide were substituted in argon shielding gas and its corresponding improvement in the mechanical, microstructural, machining, and wear aspects of the dissimilar AISI 310–AISI 2205 joints was studied. Weld bead studies, tensile, and weld region microhardness were conducted. X-ray diffraction studies revealed joint intermetallics, and microstructural evaluation was conducted. Machining studies were conducted using drilling experiments. Using local analysis and global analysis, the cutting force variations in the feed direction and cutting direction were studied. Wear tests revealed that the variations in traction force, specific wear rate, coefficient of friction and tribo wear mass loss were studied. A considerable improvement in wear characteristics of AISI 310–AISI 2205 joints was observed by substituting CO2 and N in shielding gas.

Optimization of welding parameters and study on mechanical and pitting corrosion behavior of dissimilar stainless steel GTA welds

Optimization of welding parameters and study on mechanical and pitting corrosion behavior of dissimilar stainless steel GTA welds

Microstructure and Properties of Press-Bonded Dissimilar Stainless Steel and Mild Carbon Steel Ingots

Dissimilar steel welds between stainless and mild steels are necessary for the efficient utilization of stainless steels in construction. In the present work, a dissimilar large-sized steel ingot was fabricated by press bonding a Q235 steel to a SUS 304 steel at 1100–500 °C. The microstructure of bonded interfaces has been characterized by scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy, together with tensile tests to evaluate the bonding strength. It has been demonstrated that a strong-bonded, high-quality, dissimilar steel ingot could be fabricated by press bonding. The (Fe, Cr)3C carbide is present in the narrow zone of diffusion-bonded stainless steel and mild steel. Interestingly, the maximum hardness is not too high to make the transition zone brittle but enough to constrain the narrow soft ferrite during tensile and fatigue tests, causing the final fracture to occur in the mild steel region rather than the bonding interface.

A comprehensive assessment of the galvanic corrosion behavior of an electrically assisted pressure joint of dissimilar stainless steel alloys under uniaxial tensile stress

The effect of uniaxial tensile stress on the galvanic corrosion behavior of a dissimilar joint of stainless steel alloys is investigated in 0.5 M Na2SO4 electrolyte solution at room temperature. The experimental stress-corrosion test results reveal that the application of uniaxial tensile stress causes a decrease in the corrosion potential and an increase in the corrosion rate compared to the nonstressed specimen. A numerical model is established and validated using the results from the experimental stress-corrosion tests. Consequently, a series of case studies is presented to investigate the galvanic corrosion behavior of the joint under some applied tensile strains.

Effect of activated fluxes during welding of dissimilar stainless steels using semi-automatic setup

ABSTRACT In the present work, two dissimilar metals austenitic AISI 304 and 316 stainless steels were welded with duplex 2205 using semi-automatic bi-directional GMAW setup to appraise the microstructural and mechanical behavior of the welded joints. Three different activated fluxes i.e. SiO2, TiO2 and CrO3 were used to enhance the depth of penetration during joining of different stainless steels grades. Various process parameters such as welding current, voltage, filler wire, gas flow rate and activated flux were varied to observe their influences on joint tensile, bending strength, microhardness and microstructural properties. The experiments were designed using mixed level L18 orthogonal array of Taguchi method. Tensile strength was observed to be considerably dependent on the low gas flow rate, whereas welding current and activated flux influenced the toughness. The most significant effect on the bending strength and toughness was experienced with the use of SiO2 activated flux.

Stress corrosion cracking of friction stir welded AISI 304 and 316 L dissimilar steel alloys

This study investigated the corrosion and SCC susceptibility of Friction stir welded AISI 304 and 316L similar and dissimilar stainless steel. In Fusion welding process (SMAW, GMAW, and GTAW) high temperatures are used, because of high operating temperature the heavy residual stress led to the severe cracking in the weldments. To overcome these problems, low operating temperature friction stir welding (FSW) technique was employed to fabricate stainless steel joints. Microstructural analysis has been made using optical microscopy (OM) and SEM. Tensile test was carried out to evaluate the mechanical properties of weld joints. Mechanical result indicates that the ultimate tensile strength of welded metal is higher than the base metal. Based on this study to draw conclusions and give recommendations for best practice in assessing susceptibility to SCC to pulp and paper mills.

Microstructural evolution and fatigue performance of dissimilar solid-state joints of SUS316L and SUS410

Dissimilar stainless steels 316L (SUS316L) and SUS410 in a cylindrical butt configuration are solid-state joined along the cylinder axis by electrically assisted pressure joining (EAPJ). In EAPJ, different electric current densities are applied during compressive plastic deformation to investigate the effect of electric current density on joint performance. The microstructure analysis confirms that solid-state joints without macro- and micro-defects are fabricated through elemental diffusion and recrystallization during EAPJ. The effect of electric current density on the formation of martensite and subsequently on the variation of hardness is revealed by the grain average image quality maps and their relevant area distribution. The results of quasi-static tensile tests show that the fracture behavior of the joint is strongly affected by the applied electric current density. The fatigue behavior of joints with a higher tensile strength (SUS410 base metal fracture) is also evaluated by the S–N curve under a certain confidence level using two-parameter Weibull distribution. Finally, the fracture mechanism is investigated by examining the fracture surfaces from fatigue failure. The fracture morphology under high stress level exhibits a mixed fracture mode of base metal and interface fracture, while the fracture under low stress level exhibits interface fracture.

Fracture morphology of GTAW welding of dissimilar duplex stainless steels exposed to H2S corrosion

Fracture morphology of GTAW welding of dissimilar duplex stainless steels exposed to H2S corrosion

GTA Welding Dissimilar of AISI 309 to AISI 201 Stainless Steels by Using AISI 308L Filler Metals

The aim of the study to investigate the effect of welding current on the microstructure and mechanical properties of gas tungsten arc welding (GTAW) for dissimilar austenite Stainless steel (AISI 309 and 201). Three models of welding currents have been used and their effect on microstructure and mechanical properties investigated. The results reveal that increase of welding currents improved the ultimate tensile strength (UTS) however, the hardness of the weld zone and Heat Affected Zone (HAZ) are similar. On the other hand, the microstructure of base metal AISI 309 and 201of austenite, ferrite structure, and ẟ ferrite of AISI 309 stainless steel were observed.

On the application of bipolar electrochemistry for simulating galvanic corrosion behaviour of dissimilar stainless steels

The application of a bipolar electrochemistry technique to simulate the galvanic corrosion behaviour of dissimilar stainless steels is introduced. The technique allows comparison of the bipolar response by controlling the extent of localised corrosion as a function of an applied offset potential. The setup was explored to simulate the galvanic performance of type 420 ferritic and type 304L austenitic stainless steels, yielding information about the anodic vs. cathodic behaviour of these materials when in close proximity to each other. The introduced approach provides a novel methodology for simulating the galvanic corrosion behaviour of stainless steels.

Radiographic Testing of 420 and 304L Dissimilar Stainless Steels after TIG Welding

SAE/AISI 304L ostenitik paslanmaz celikler oksitleyici ortamlardaki korozyon dayanimlari icin tercih edilirken, SAE/AISI 420 martenzitik paslanmaz celikler genel olarak atmosferik korozyona karsi dayanim amacli kullanilmaktadirlar. Martenzitik paslanmaz celikler bircok alasimli celiklere yakin degerlerde yuksek mekanik dayanim degerleri sergilerken bunun yaninda ostenitik paslanmaz celikler yuksek ve dusuk sicakliklarda yuksek tokluk degeri ortaya koyarlar. Bu iki farkli alasim grubu ekonomik kosullar ve mekanik ozellik yaklasimlarindan dolayi bir yapida bir arada kullanilabilirler. Kaynakli baglantilarin kaynak metalleri ve isinin tesiri altindaki bolgeleri, guvenilir bir kaynakli baglanti elde etmek icin; penetrant, ultrasonik ve radyografik muayene yontemleri gibi tekniklerle detaylica incelenmelidir. Bu calismada; 3 mm kalinliktaki SAE/AISI 304L ostenitik paslanmaz celik levha ile 3mm kalinlikta SAE/AISI 420 martenzitik paslanmaz celik levha TIG (Tungsten Asal Gaz) kaynak yontemiyle saf argon koruyucu gazi altinda ER312, ER316L, ER2209 olmak uzere 3 farkli ilave tel kullanilarak birlestirilmistir. TIG kaynak teli bilesiminin kaynak metalinde olusabilecek kusurlara etkileri incelenmistir. Bu amacla, numunelerin kaynak metallerinin tamami x- isinlari radyografik muayenesi ile test edilmistir. ER312 ve ER2209 TIG teli ile birlestirilen numunelere kiyasla, ER 316L TIG teli ile birlestirilmis olan numunelerin kaynak metalinde, dolgu telinin en dusuk krom ve en yuksek nikel icerigine sahip olusu neticesinde en dusuk miktarda oldugu dusunulen gevrek karburlere bagli olarak en dusuk oranda sureksizlik tespit edilmistir.

Research of Technology for Repair of Heat Exchangers of Nuclear Power Plants by Laser Welding

Extending the lifetime of energy facilities is extremely important today. This is especially true of nuclear power plants, the closure (or modernization) of which poses enormous financial and environmental problems. High-quality repair of reactors can significantly extend their service life. One of the critical parts is heat exchangers, the tubes of which quite often fail. Sealing, as a type of repair of heat exchanger tubes by the plugs, is promising provided that the joint quality is high. Practical experience in the use of welding to solve this problem has shown the need to search technological solutions associated with increasing the depth of penetration and reducing the area of thermal effect. The aim of the work was to develop a highly efficient technology for repair and extension of service life of heat exchangers of nuclear power plants based on the results of studying the technological features of laser welding of joints of dissimilar austenitic steels AISI 321 and AISI 316Ti in the vertical spatial position. Based on the results of the analysis of mechanical test data, visual and radiographic control, impermeability tests and metallographic studies of welded joints, the appropriate modes of laser welding of plugs have been determined. The principal causes of defects during laser welding of annular welded joints of dissimilar stainless steels are determined and techniques for their elimination and prevention of their formation are proposed. Based on the results of the research, technological recommendations for laser welding of plugs in the heat exchange tube of the collector are formulated, which significantly improves the technology of repair of steam generators of nuclear power plants and extends the service life of reactors.

Interfacial properties of friction stir lap welded 430/304 stainless steels using Cu interlayer

Friction stir lap welding of 304 and 430 dissimilar stainless steels was performed by using Cu interlayer. The joint was formed by two kinds of metallurgical processes. 430 stainless steel and Cu foil were joined by brazing process because of the melting of Cu, and the 430/Cu interface consisted of Fe- and Cu-based solid solutions. 304 stainless steel and Cu foil were joined by solid state diffusion process due to low interface temperature, and the Cu/304 interface contained Fe- and Cu-based solid solutions. The maximum shear load of the joint with Cu interlayer reached 2776 N, increased by 62% compared to the joint without interlayer. Cu interlayer promoted the diffusion of atoms at the interface and decreased the interfacialstress, thus it can significantly improve the performance of the joint.

MICROSTRUCTURAL AND TRANSIENT THERMAL ANALYSIS OF TIG WELDED JOINT SAE 2205 WITH AISI 304 WITH AISI 308 FILLER METAL

In the present work SAE 2205 is welded with AISI 304 using AISI 308 filler wire. TIG welding current was maintained at 110, 120 and 130 Amp and the voltage was set at 40 Volt. A constant welding speed of 0.5 mm/s was maintained for all the experiments. The optical microscopic examination of the welded samples revealed the presence of recrystalized zone, mushy zone at the weld metal SAE 2205 side and columnar grains adjacent to the heat affected zone. The maximum hardness value of Rc 29 was observed in the welded region. The increase in hardness value was attributed to absorption of oxygen in the weld metal during welding and solidification of the weld metal. A maximum yield strength of 354 MPa and an ultimate tensile strength value of 549 MPa were obtained for the samples processed at 130 Amp. Combined transient thermal and stress analysis was performed for the dissimilar stainless steel joints made between SAE 2206 and AISI 304L. A maximum Von Mises stress of 85 MPa was obtained for the weld joints made between stainless steel AISI 304 and stainless steel SAE 2205.

On the Use of Laser Beam Welding for Austenitic Stainless Steel Type 316L and Stainless Steel Type 304 for Aerospace Applications.

Currently wide range of aircraft parts have been welded by using laser beam welding. In this paper we have analyzed the strength of laser beam welded joint of stainless steel materials 316 L and 304. The Micro and Macro welding techniques are used for dissimilar stainless steel materials. The metal sheets are welded with a laser power of 1000 w with a bead width of 0.5 mm on both sides of the sheet by using micro laser beam welding and the macro laser beam welding is used to weld the metal sheets with 1800 w laser power along with a bead width of 3mm on one side of the sheet. The strength and mechanical properties of laser beam welded samples are found out by subjecting it to various tests such as Tension test, Bend test and Hardness test. Since stainless steel used in the aircraft parts are subjected to high temperature in the engine exhaust part, these samples are heated to temperature of 1040ºC. Aircraft icing occurs on parts of aircraft, where temperature falls below 0ºC, hence laser beam welded samples are cooled to a temperature of -30ºC. The behavior of laser beam weld portions under these conditions are studied. The Microstructure of the welded sample is obtained from the Scanning electron microscope is also discussed. The results obtained from the tensile test are compared with the structural analysis done using Finite Element Analysis. From the results we found that, macro welded sample is having good tensile strength of 582.753 MPa and no cracks were occurred during the bending test.