High Arc Research Articles

TIG assisted surface modification of Ti-6Al-4V with B4C, SiC particles

This research article assesses the improved hardness and wear behaviour of Ti–6Al–4V (Titanium-6Aluminium-4Vanadium) ex-situ produced composite case on its surface by TIG Arcing. This method is recognized for its potential to modify the surface of various metallic substrates by carefully controlling the melting and solidification of the substrate using a significantly less expensive high density electric arc heat source of the widely used autogenous (without filler) gas tungsten arc welding (GTAW) process.The molten base and the hard particles in the applied coating through reinforcement led to the development of hard surface characteristics in the Ti-6Al-4V surface matrix. The hard particles that have been reinforced by using TIG arcing to develop a hard wear-resistant surface coating are boron carbide (B4C) and silicon carbide (SiC). The presence of hard particles on the surface of Ti64 has been verified by XRD Pattern and EDS examination. The effect of different reinforced particles on the wear behaviour as well as the hardness of the modified surface has been studied by comparing the Ti64 modified surface without reinforcement and the as-built Ti64 surface samples. Vickers micro hardness testing measures the hardness of the modified particulate surface composite and demonstrates a significant increase in hardness, ranging from 1.5 to 2 times that of the base metal and wear tests confirm that the surface-coated samples of B4C and SiC on the base metal, showed a reduction in wear rate of approximately 55% and 45% respectively, compared to the base metal.

Generation of multiply charged metal ions in a high current short pulse vacuum arc

We have studied the plasma composition of a high current short pulse vacuum arc discharge with different cathode materials: lanthanum, gadolinium, lead, silver, and tin. We find that for optimal vacuum arc discharge parameters – arc current pulse duration about 2 μs and amplitude about 3 kA – the maximum ion charge state is 11+ and mean ion charge state from 7.8+ for tin to 9.6+ for lanthanum. The mean ion charge state for different materials depends on the discharge voltage and the energy required for ionization to maximum charge state. The cathode surface heats to a temperature of 700 °C–1100 °C in the course of the arc current pulse, depending on the cathode material, and the cathode surface of low melting point metals such as lead and tin melts to a depth of 5 μm and 10 μm, respectively. Surface melting does not lead to change in plasma ion composition, since the ion flux from the cathode considerably exceeds the evaporated atom flux.

The microstructure and properties of copper coating fabricated by high velocity arc spraying

In this paper, the conductive copper coating on the surface of silicon nitride ceramics was fabricated by high velocity arc spraying with copper wires. The results indicate that copper coating with porosity less than 2.4 % was obtained, and a metallurgical bonding between the copper coating and the ceramic substrate. The copper coating presented a high microhardness of 303HV which surpassed the copper alloy and the thin film deposited by electrodeposition. Moreover, the copper coating exhibited a superior conductivity of 27.5 MS/m. Due to the rougher surface of the copper coating compared to copper sheet, a jagged intermetallic compound (IMC) layer was promoted during soldering process. It is feasible that an excellent conductive copper coating on the surface of ceramic substrate can be fabricated by high velocity arc spraying.

Characterization of A-site doped PrBaCo2O5+δ perovskites as cathode materials for IT-SOFCs

Creating highly efficient and durable cathodes persists as a formidable task in the realm of intermediate temperature solid oxide fuel cells (IT-SOFCs). Hence, we present a double perovskite oxide, Pr0.6Sr0.4BaCo2O5+δ (PS0.4BC), and its electrocatalytic activity is thoroughly investigated. The XRD test is carried out and a notable transformation in the phase structure is observed upon the introduction of Sr2+ ions into the PBC matrix. That is, the phase structure of the material changes from double perovskite structure to single perovskite structure. Through the TG and TEC test that the introduction of Sr2+ ions into the lattice can create additional sites for oxygen vacancy formation and reduce TEC values. Further verify that Sr doping can enhance the concentration of oxygen vacancies of the material. The PS0.4BC cathode material exhibits remarkably low polarization resistance, achieving an impressive value of 0.027 Ω cm2 at an operating temperature of 800 °C. Oxygen partial pressure test shows that as the oxygen partial pressure decreases, there is a notable increase in impedance, particularly evident in the low frequency region of the Nyquist plots. This indicates that the oxygen content has obvious effects on the low-frequency processes. When the oxygen partial pressure exceeds 0.05 atm, the oxygen adsorption-dissociation and diffusion process is the rate-limiting step in the ORR. However, when the oxygen partial pressure is less than 0.05 atm, the formation of lattice oxygen through the combination of oxygen ions and oxygen vacancies processes is the rate-limiting step. Compared PBC cathode material, the more pronounced changes in the high frequency arc of the PS0.4BC cathode at the same oxygen content. It shows that Sr doping significantly changes the high frequency process. After doping, the oxygen vacancy concentration increases, which facilitates the occurrence of the charge transfer process at high frequency.

Закономерности износа плазмотронов при плазменной резке толстолистового проката на токе обратной полярности

The introduction describes the features of the process of plasma cutting of various metals and alloys using reverse-polarity plasma torches with and the features of cutting thick sheets. The purpose of the work is to study the wear process of plasma torches operating on reverse polarity current when cutting thick rolled sheets of aluminum and titanium alloys. Research methods include optical and scanning electron microscopy, filming of the cutting process and visual inspection of plasma torch elements after receiving specimens. Results and discussion. The section shows the appearance of the main working elements of the plasma torch after cutting in various modes, which led to both stable and gradual wear and to catastrophic failure of the plasma torch. The results of structural studies of the main characteristic zones of nozzles and electrodes after cutting are presented. The studies carried out made it possible to establish the main reasons for the failure of the working elements reverse-polarity plasma torches. The causes of catastrophic failure of plasma torches include failure to maintain the gap between the nozzle and the electrode and melting of the channel of gas supply into the discharge chamber. The wear of nozzles and electrodes in a stable mode can be intensified due to abnormal operation of the starting arc, the presence of manufacturing inaccuracies and excess gas pressure. In conclusion, the main conclusions based on the results of the research are formulated. The process of wear of electrodes, nozzles and body elements of plasma torches during operation at high electric arc power values is described.

Arc erosion behavior of Ag-8 wt.%ZrO2 contact materials with CuO additions

To clarify the effect of CuO on the arc erosion behavior of AgZrO2 contact materials, the Ag-8 wt.%ZrO2 contact materials without and with CuO addition were prepared by the combination of three-dimensional vibrating mixing and hot-pressing sintering, and the electrical contact tests were performed 5000 times on a JF04D electrical contact testing system. The effect of CuO additive on the arc erosion behavior of Ag-8 wt.%ZrO2 contact material was studied, and the arc erosion mechanism was discussed as well. The results show that an appropriate CuO addition can significantly improve the hardness, electrical conductivity and arc erosion resistance of Ag-8 wt.%ZrO2 contact material. At 0.5 wt%CuO, the optimal combination of relative density, hardness and electrical conductivity can be achieved, which are 99.48 %, 79.0 HV and 79.3 %IACS, respectively. Furthermore, the Ag-8 wt.%ZrO2 contact material with 0.5 wt%CuO addition exhibits the lowest arc energy and shortest arc duration, least mass loss, and silver splashing as well as the formation of pores are also significantly inhibited, displaying excellent arc erosion resistance. This can be ascribed to the improved electrical conductivity and enhanced interface bonding together with CuO decomposition under high temperature arc.

Nano-Strand Formation via Gas Phase Reactions from Al-Co-Fe Reacted with CaF2-SiO2-Al2O3-MgO Flux at 1350 °C: SEM Study and Thermochemistry Calculations

The submerged arc welding (SAW) process is operated at high temperatures, up to 2500 °C, in the arc cavity formed by molten oxy-fluoride flux (slag). These high arc cavity temperatures and the complex interaction of gas–slag–metal reactions in a small space below the arc render the study of specific chemical interactions difficult. The importance of gas phase reactions in the arc cavity of the SAW process is well established. A low-temperature (1350 °C) experimental method was applied to simulate and study the vaporisation and re-condensation behaviour of the gas species emanating from oxy-fluoride flux. Energy dispersive X-ray spectroscopy (EDX) analyses and reaction thermochemistry calculations were combined to explain the role of Al as a de-oxidiser element in gas phase chemistry and, consequently, in nano-strand formation reactions. EDX element maps showed that the nano-strands contain elemental Ti only, and the nano-strand end-caps contain Co-Mn-Fe fluoride. This indicates a sequence of condensation reactions, as Ti in the gas phase is re-condensed first to form the nano-strands and the end-caps formed from subsequent re-condensation of Co-Mn-Fe fluorides. The nano-strand diameters are approximately 120 nm to 360 nm. The end-cap diameter typically matches the nano-strand diameter. Thermochemical calculations in terms of simple reactions confirm the likely formation of the nanofeatures from the gas phase species due to the Al displacement of metals from their metal fluoride gas species according to the reaction: yAl + xMFy ↔ xM + yAlFx. The gas–slag–metal equilibrium model shows that TiO2 in the flux is transformed into TiF3 gas. Formation of Ti nano-strands is possible via displacement of Ti from TiF3 by Al to form Al-fluoride gas.

Microstructure and mechanical properties of 308L steel wall fabricated using high-current manual GMAW-based additive manufacturing

This study investigates the impact of high arc current on the mechanical properties and microstructure of thin-walled material fabricated using manual GMAW wire arc additive manufacturing (WAAM). The ER308L electrodes were used to fabricate samples using high currents of150A, 170A, and 190A; voltages of11 V, 11.5 V, and 12 V; and travel speeds of400 mm/min, 435 mm/min, and 450 mm/min. It was found that increasing the current improves the mechanical properties, with optimal value in 170A. The ultimate tensile strength (UTS) increases by around 3 % from 605 ± 9 to 623 ± 8 MPa at 190A. The yield strengths (YS) are 370 ± 6, 384 ± 5, 371 ± 8, corresponding to 3.8 % increase at 170A then decrease 3.6 % at 190A. The microhardness increases 3.7 % with higher current, from 212.00 HV0.5 at 150A to 293.33 HV0.5 at 190A. The Elongation are 42.07 %, 41.8 %, and 41.3 %, slightly reduce for 150A, 170A, 190A respectively. The Microstructure analysis revealed δ-ferrite and γ-austenite dendrites, with lathy and skeletal morphology variations.

Influence of Cu distribution in thermally sprayed Cu-bearing coatings on the prevention of Desulfovibrio vulgaris corrosion

Thermally sprayed Cu-based coatings show promise for combating microbiologically influenced corrosion (MIC) within natural gas pipelines. However, the efficacy of Cu-bearing coatings against MIC over prolonged exposure to bacterial fluids remains unclear. To examine the effect of Cu distribution on the prevention of MIC, two types of Cu-containing coatings were prepared: stainless steel (SS)-Cu composite coatings and Monel 400 coatings with Cu in solid solution. These coatings were deposited using high velocity oxy-fuel (HVOF) and wire arc spray (WAS) techniques. Dynamic flow corrosion testing was utilized to examine the influence of Cu concentration and distribution on biofilm attachment and pit formation. The results show that SS-Cu composite coatings exhibit preferential Cu dissolution when exposed to Desulfovibrio vulgaris solution, significantly reducing biofilm attachment over the short-term period (7 days) which correlated with the release rate of Cu ions. However, accelerated Cu ion release led to Cu2S deposition on sample surfaces, diminishing anti-biofilm properties with prolonged exposure (28 days). Pit depth measurements indicated a correlation between pit formation and Cu ion release throughout the exposure period, with bio-generic H2S likely contributing to increased pit corrosion. Utilizing the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE), the anti-MIC performance of coatings were ranked based on biofilm thickness, biofilm coverage, pit depth, antimicrobial effect, and splat thickness. The ranking placed WAS Monel with Cu in solid solution as the most effective coating, attributed to its thin laminar structure, enhanced corrosion resistance, and antimicrobial properties. Cu in solid solution was concluded to be more effective in resisting MIC of Desulfovibrio vulgaris under dynamic flow conditions compared to Cu existing as segregated phase within composite coatings.

The Effect of Addition Amount of Chromium Iron on the Bonding Strength between Alloy Steel Surfacing Layer and Steel Base Metal

Fe-C-Cr-Nb alloy steel surfacing layers with different contents of C and Cr were prepared on 45 steel base metal by selfshielded flux-cored wires with distinct amounts of high carbon chromium iron addition and melt arc surfacing. The composition and microstructure changes of the surfacing layer were tested and analyzed. The surfacing test plate was processed into a pulling specimen, and the bonding strength between the surfacing layer and the 45 steel base metal was tested with a self-designed pulling test method. The fracture location of the pulling specimen and fracture characteristics were observed by a metallurgical microscope and a scanning electron microscope. The result shows that with the increase of the amount of high carbon chromium iron added to flux-cored welding wire, the content of C and Cr in the surfacing layer increases, and the NbC hard phase disperses. The microstructure of the steel matrix changes from mixed martensite + residual austenite to high carbon martensite + residual austenite, and then independent austenite appears. The hardness of the surfacing layer first increases and then decreases. The bonding strength between the surfacing alloy and the 45 steel base metal first decreases and then increases, and the fracture location is at the bottom of the surfacing layer or the fusion zone with mostly quasi-cleavage characteristics. When the additional amount of high carbon chromium iron reaches 13%, thee pulling specimen exhibits significant deformation with the highest bonding strength, and the fracture is close to the fusion line, where there are numerous tearing edges and shallow dimples.

Improvement of the control system with the drive of high voltage arc furnaces

The article presents a method for improving the control system of electric motors driving the electrodes of high-voltage arc furnaces. The developed method today in the field of metallurgy is of great importance in solving problems such as at the first stage of melting and casting metal in arc steelmaking furnaces, when the electrodes are initially lowered into the working bath, the connection point breaks as a result of contact with a metal plate, the incompatibility of the formation of an electric arc on the electrodes, holding the electrodes at a certain distance from the metal charge. Also, automatic control of the speed of movement of the electrodes, i.e. (the time of formation of an electric arc in the electrodes, which reduces the speed of its movement, the time of lifting the electrodes, lowering, increasing the speed of movement), is relevant for solving problems such as welding electrodes into a metal shackle. The main purpose of introducing this method into practice is to reduce electricity consumption and ensure reliable operation of high-voltage electric arc furnaces by reducing the melting time of metal.

Abstract 2549: Activity-regulated cytoskeleton-associated protein (ARC) gene expression is associated with high infiltration of stromal cells and immune cells, but with less cancer cell proliferation and better overall survival in ER-positive/HER2-negative breast cancers

Abstract Introduction: Recently peritumoral lidocaine infiltration prior to removal was reported to be associated with better survival in early-stage breast cancer (BC). This led us to hypothesize that innervation to the tumor affects its biology and patient survival. Activity-regulated cytoskeleton-associated protein (ARC) gene expression is known to be regulated by neuronal activity. Therefore, we studied the clinical relevance of ARC gene expression as a surrogate of neuronal activity in BC. Methods: Sweden Cancerome Analysis Network-Breast (SCAN-B (GSE96058), n=3273) cohort was analyzed, and the results were validated using The Cancer Genome Atlas (TCGA, n=1069). Results: ER+/HER2- and Luminal A type cancers expressed significantly higher ARC compared to the other subtypes in both cohorts (p<0.005). In the tumor microenvironment, the stromal cells (fibroblasts, endothelial cells and adipocytes) were all found to be significantly infiltrated in high ARC BC (p<0.01). Multiple immune cells were significantly infiltrated in high ARC BC, including CD8, CD4 memory cells, helper type II T cells, regulatory T cells, M1 and M2 macrophages, dendritic cells and B cells (all p<0.03 in both cohorts). In terms of cancer characteristics, there was no difference in silent or nonsilent mutations, single nucleotide variant or indel neoantigens between tumors with low or high ARC expression. However, high ARC BC was significantly associated with less homologous recombination deficiency, intratumor heterogeneity and fraction altered mutation rate compared to low ARC BC in TCGA (p<0.001). High ARC expression was significantly associated with smaller tumor size (p<0.001) and without lymph node metastasis in the SCAN-B cohort (p<0.02), and less Stage IV disease in the TCGA cohort (p<0.02); however, these results were not validated by the other. High ARC BC was significantly associated with lower Nottingham histologic grade and lower MKi67 expression in both cohorts (p<0.001). Cell proliferation-related gene sets in the Hallmark collection (E2F targets, G2M checkpoint, and MTORC1 signaling) were significantly less enriched to high ARC BC consistently in both cohorts. Overall survival (OS) was significantly better in high ARC BC in the ER+/HER2- subtype consistently in both cohorts (p<0.01) and when including all subtypes in the SCAN-B cohort (p<0.001); however this was not validated in TCGA. No significant difference in OS was found between low and high ARC gene expression in triple negative BC in either cohort. Conclusion: ARC gene expression as a surrogate of neuronal activity in BC was associated with high infiltration of stromal cells and immune cells but with less cancer cell proliferation and better overall survival, particularly in the ER+/HER2- subtype. Citation Format: Gabrielle Yee, Rongrong Wu, Takashi Ishikawa, Kazuaki Takabe. Activity-regulated cytoskeleton-associated protein (ARC) gene expression is associated with high infiltration of stromal cells and immune cells, but with less cancer cell proliferation and better overall survival in ER-positive/HER2-negative breast cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2549.

Numerical Study of Large Contact Diameter and Gap High Current Vacuum Arc

Numerical Study of Large Contact Diameter and Gap High Current Vacuum Arc

Fault Analysis of 35kV Outdoor Vacuum Circuit Breaker Pillar Porcelain Sleeve

In order to further clarify the failure mechanism of the pillar porcelain insulator, the field inspection, the microscopic morphology analysis and material analysis of the ceramic shell of the pillar under a 35kV outdoor vacuum circuit breaker were carried out. The results show that the direct cause of the failure is the discharge between the high voltage conductor inside the porcelain sleeve and the weak part of the porcelain sleeve, and the high temperature arc leads to the bursting of the porcelain sleeve. The indirect cause of the failure is the loose porcelain of the porcelain sleeve, the existence of internal layering, uneven composition and micro-pores and other macro and micro defects, and the original defects of the inner surface of the porcelain sleeve, such as local unglazed and poor quality of the porcelain sleeve manufacturing process. In the long-term outdoor operation, the external moisture and gas penetrate into the porcelain sleeve, which leads to the deterioration of the insulation performance of the porcelain sleeve, and eventually leads to failure.

Research on Noise Reduction Modification Design of High Speed EMU Traction Arc Toothed Cylindrical Gears

Aiming at the deficiencies of the traction helical gear transmission system when the EMU is running at high speed, this paper proposes and designs a kind of arc toothed cylindrical gear adapted to the traction of higher speed EMU. A parametric arc toothed cylindrical gear model was constructed using CREO, and its dynamic contact characteristics and acoustic response characteristics were analyzed under sustained operating conditions using the finite element boundary element method. The design of a tooth profile combined with the radius of the arc toothed line of the comprehensive trimming program put forward a virtual trimming prototype method through MATLAB and CREO reconstruction gear, and trimming before and after the gear transmission simulation experiments occurred for comparison and analysis. This study shows that the traction arc toothed cylindrical gear comprehensive modification method proposed in this study achieves better dynamic performance optimization, effectively reduces the contact stress and radiation noise of the gear transmission, and provides a theoretical basis for the development of a new generation of high-speed EMU stock traction drive systems.

Simulation of High Current Vacuum Arc with Hybrid Cathode Attachment

Simulation of High Current Vacuum Arc with Hybrid Cathode Attachment

Effect of Ti on the microstructure and properties of Cu–Cr alloy

Cu–Cr–Ti alloy was successfully prepared by vacuum melting, solution treatment at 960 °C for 1 h, 80 % cold rolling and aging at 500 °C for 1 h. The effect of Ti content on the microstructure was characterized by Scanning electron microscope (SEM) and Transmission electron microscope (TEM). Their tensile strength, electrical conductivity, thermal stability, wear resistance and arc erosion resistance were also measured. The results showed that Ti can form the Ti0.77S phase with S, which can prevent the occurrence of sulfur embrittlement. And Ti can segregate around the Cr precipitates, hindering their growth. Therefore, the tensile strength, hardness, high temperature softening resistance, wear resistance and arc erosion resistance improved with the increase of Ti content. But the electrical conductivity decreased sharply since Ti was mainly solidly dissolved in the matrix. What's more, the electrical conductivity decreased sharply and other properties did not improve when the content increased from 0.066 wt% to 0.098 wt%, that is, the comprehensive performance was the best when the Ti content was 0.066 wt%. The tensile strength was 551 MPa, electrical conductivity was 78.3%IACS and the friction coefficient was 0.33. This work provides effective ideas for preparing copper alloys with desired properties.

A Novel Planning and Delivery Technology: Dose, Dose Rate and Linear Energy Transfer (LET) Optimization Based on Spot-Scanning Proton Arc Therapy FLASH (SPLASHLET)

To achieve a high conformal dose with Linear Energy Transfer (LET) optimized FLASH proton therapy, we introduced a new planning and delivery technique concept, the voxel-wised optimization of LET distribution and dose rate based on scanning arc therapy (SPLASHLET) MATERIALS/METHODS: The algorithm optimizes (1) the clinical dose-volume constraint based on dose distribution and (2) the clinical LET-volume constraint based on LET distribution using Alternating Direction Method of Multipliers (ADMM) with Limited-memory BFGS solver by minimizing the monitor unit (MU) constraint on spot weight and (3) the effective dose-average dose rate by minimizing the accelerator's beam current sequentially. Such optimization framework enables the high dose conformal dynamic arc therapy with the capability of LET painting with voxel-based FLASH dose rate in an open-source proton planning platform (MatRad, Department of Medical Physics in Radiation Oncology, German Cancer Research Center-DKFZ). It aiming to minimize the overall cost function value combined with plan quality and voxel-based LET and dose rate constraints. Three representative cases (brain, liver and prostate cancer) were used for testing purposes. Dose-volume histogram (DVH), LET volume histogram (LVH) dose rate volume histogram (DRVH) and dose rate map were assessed compared to the original SPArc plan (SPArcoriginal). SPLASHLET plan could offer comparable plan quality compared to SPArcoriginal plan. The DRVH results indicated that SPArcoriginal could not achieve FLASH using the clinic beam current configuration, while SPLASHLET could significantly not only improve V40Gy/s in target and region of interest (ROI) but also improve the mean LET in the target and reduce the high LET in organ at risk (OAR) in comparison with SPArcoriginal (Table 1). SPLASHLET offers the first LET painting with voxel-based ultra-dose-rate and high-dose conformity treatment using proton beam therapy. Such technique has the potential to take full vantage of LET painting, FLASH and SPArc.

Electrical Characterization and Modeling of High Frequency Arcs for Higher Voltage Aerospace Systems

Arcing in future high-voltage aerospace systems could occur more frequently and cause irreversible damage to electrical components, system structure and increase the risk of fire. While arcs seen in low-voltage aerospace systems tend to be long-duration and low-energy events, higher power but short-duration arcs may occur in high-voltage aerospace systems if they are readily detectable by system protection. This paper investigates the characteristics of high current arc faults generated at the AC frequencies expected in future rotating machines used for higher voltage aerospace systems. As such, arcs with a peak current up to 4.6 kA are generated at frequencies in the range of 0.5-2 kHz using an underdamped RLC circuit, under pressures of 0.2-1 bar absolute. High frequency arcs exhibit a similar characteristic to lower frequency arcs. A reduction in pressure results in lower arc voltage and arc power. Arcing tests at atmospheric pressure may therefore represent a worst-case scenario and the development of a low-pressure test environment may not be necessary. A black box model is developed to provide good agreement with experimental arc voltage waveforms for different parameters investigated in this study. This is a generalized modeling approach to estimate high-frequency high-voltage arcing characteristics without recourse to experiment.

Mechanical characteristics and stretch-bend failure analysis on ultra high frequency pulsed gas tungsten arc welded thin FSS 409/430 dissimilar joints

The Mechanical and Stretch-Bend Failure studies on Ultra High Frequency Pulsed Gas Tungsten Arc Welded dissimilar joints of AISI409-AISI430 Ferritic Stainless Steels were conducted. Welding was conducted with 5 ultra high frequencies (50 Hz, 150 Hz, 250 Hz, 350 Hz, 450 Hz). Mechanical characteristics evaluation on the joints included tensile strength, microhardness variations across the welds and creep. Microstructural and metallurgical investigations included weld cross section evaluation, comparing grain variations in high, medium and low thermal heat affected zones, weld zones and base material region. Stretch bend failure studies included studies on angular distortion, fracture limit strain, and coefficient of friction. Tests revealed that joints welded at 350 Hz was better, compared to other joints. Dissimilar AISI409-AISI430 joint fabricated at 350 Hz exhibited 267 ± 3 MPa as yield and 409 ± 6 MPa and as ultimate tensile strength. Its creep fracture duration was 72.7 min (highest among the joints). Microstructural studies revealed grain growth, partially coarse and partially fine grains in heat affected zones. Depending on the difference in grain sizes, on both sides of the welds, heat affected regions were identified as three distinct zones. In AISI430 side; high temperature austenitic, martensitic, delta ferrites and in AISI409 side; needle like martensitic structures, mixture of ferritic-austenitic, δ-ferrite with carbide precipitation were found in high, medium and low thermal heat affected zones, respectively. On increasing the ultra high frequency pulses, angular distortion increased, fractures changed from tensile/shear type to mixed type. In shear bend tests, on increasing the ratio of radius: thickness, fracture limit strain on outer surface, across sheet thickness, due to stretching increased.