Changes In Temperature Gradient Research Articles

Numerical analysis on fluid flow and heat transfer in the smelting furnace of mitsubishi process for Cu refining

To understand complex behavior in the smelting furnace of Mitsubishi continuous process for copper refining, comprehensive 3-D numerical simulation and field experiment were performed. The numerical simulation results showed that strong and complex velocity fields of gas, matte and slag were generated in the furnace and large amounts of matte and slag were splashed into the gas area. Temperature measurements at the lance during field operation revealed that wide range of temperature variation appeared depending on the injection condition of concentrates. Numerical simulation results provided good agreements with experiments results and showed that the chemical reaction induces temperature increase during gas injection period. On the other hand, lance temperature is decreasing because of cold concentrates during gas and particles injection period. From the FFT analysis results, the fluctuations of matte and slag volume fraction near the lance induce temperature fluctuations of the lance. Through these experimental and simulation results, it was revealed that the lances in the smelting furnace were exposed to severe conditions such as high temperature, repeated large temperature change and cyclic change of large temperature gradient across the thickness.

Thermal Energy during Irreversible Electroporation and the Influence of Different Ablation Parameters

PurposeIrreversible electroporation (IRE) uses high-voltage electric fields to achieve cell death. Although the mechanism of IRE is mainly designated as nonthermal, development of secondary Joule heating is inevitable. The study purpose was to gain understanding of temperature development and distribution during IRE. Materials and MethodsIRE was performed in a transparent polyacrylamide gel resembling soft tissue. Mechanical effects, changes in temperature gradient, and absolute temperature changes were measured with three different optical techniques (high-speed, color Schlieren, and infrared imaging) to investigate the effect on temperature of variations in voltage, pulse length, active tip length (ATL), interelectrode distance, electrode configuration (parallel, convergent, and divergent), and sequential pulsing (pulse delivery interrupted by breaks). The total delivered energy was calculated. ResultsA temperature gradient, starting at the tips of both electrodes and expanding toward each other, developed immediately with pulse delivery. Temperatures increased with increasing voltage (by 2.5°C–40.4°C), pulse length (by 5.3°C–9.8°C), ATL (by 5.9°C–17.6°C), and interelectrode distance (by 7.6°C–21.5°C), in accordance with higher energy delivery. Nonparallel electrode placement resulted in heterogeneous temperature distribution with the peak temperature focused in the area with the shortest interelectrode distance. Sequential pulse delivery significantly reduced the temperature increase compared with continuous pulsing (4.3°C vs 11.7°C). ConclusionsVoltage, pulse length, interelectrode distance, ATL, and electrode configuration each have a strong effect on temperature development and distribution during IRE. Sequential pulsing reduces the extent and volume of thermal distribution and may prove beneficial with respect to procedural safety.

The effect of thermal conditions on CO2 distribution in a greenhouse

ABSTRAC: An experiment was conducted to determine the extent to which the distribution of CO2 depended on the thermal conditions within a greenhouse. The CO2 levels and the change in the horizontal temperature gradient were measured throughout the greenhouse. The appropriate level of CO2 and the concentrated mass of CO2 were analyzed at predetermined points to verify the relation between CO2 and temperature to establish whether a constant distribution existed throughout the facility. As a result, when using the membrane system, the CO2 concentrations external and internal to the greenhouse were measured to be 380~440 ppm and 1020 ppm, respectively. The efficiency of the membrane system was shown to be about 268%. The highest CO2 concentration was about 1000 ppm near the floor, where the temperature was the lowest. In contrast, at a height of 2.50 m, where the temperature was the highest, the CO2 concentration was the lowest at about 400~500 ppm.

Tightly linked zonal and meridional sea surface temperature gradients over the past five million years

The climate of the tropics and surrounding regions is defined by pronounced zonal (east–west) and meridional (equator to mid-latitudes) gradients in sea surface temperature. These gradients control zonal and meridional atmospheric circulations, and thus the Earth’s climate. Global cooling over the past five million years, since the early Pliocene epoch, was accompanied by the gradual strengthening of these temperature gradients. Here we use records from the Atlantic and Pacific oceans, including a new alkenone palaeotemperature record from the South Pacific, to reconstruct changes in zonal and meridional sea surface temperature gradients since the Pliocene, and assess their connection using a comprehensive climate model. We find that the reconstructed zonal and meridional temperature gradients vary coherently over this time frame, showing a one-to-one relationship between their changes. In our model simulations, we systematically reduce the meridional sea surface temperature gradient by modifying the latitudinal distribution of cloud albedo or atmospheric CO2 concentration. The simulated zonal temperature gradient in the equatorial Pacific adjusts proportionally. These experiments and idealized modelling indicate that the meridional temperature gradient controls upper-ocean stratification in the tropics, which in turn controls the zonal gradient along the equator, as well as heat export from the tropical oceans. We conclude that this tight linkage between the two sea surface temperature gradients posits a fundamental constraint on both past and future climates. Global mean temperatures during the Pliocene epoch were warmer than at present, with a shallow meridional temperature gradient. Numerical simulations suggest that since the Pliocene, the meridional and zonal temperature gradients have varied in tandem.

Dynamic Performance of Maximum Power Point Trackers in TEG Systems Under Rapidly Changing Temperature Conditions

Characterization of thermoelectric generators (TEG) is widely discussed and equipment has been built that can perform such analysis. One method is often used to perform such characterization: constant temperature with variable thermal power input. Maximum power point tracking (MPPT) methods for TEG systems are mostly tested under steady-state conditions for different constant input temperatures. However, for most TEG applications, the input temperature gradient changes, exposing the MPPT to variable tracking conditions. An example is the exhaust pipe on hybrid vehicles, for which, because of the intermittent operation of the internal combustion engine, the TEG and its MPPT controller are exposed to a cyclic temperature profile. Furthermore, there are no guidelines on how fast the MPPT must be under such dynamic conditions. In the work discussed in this paper, temperature gradients for TEG integrated in several applications were evaluated; the results showed temperature variation up to 5°C/s for TEG systems. Electrical characterization of a calcium–manganese oxide TEG was performed at steady-state for different input temperatures and a maximum temperature of 401°C. By using electrical data from characterization of the oxide module, a solar array simulator was emulated to perform as a TEG. A trapezoidal temperature profile with different gradients was used on the TEG simulator to evaluate the dynamic MPPT efficiency. It is known that the perturb and observe (P&O) algorithm may have difficulty accurately tracking under rapidly changing conditions. To solve this problem, a compromise must be found between the magnitude of the increment and the sampling frequency of the control algorithm. The standard P&O performance was evaluated experimentally by using different temperature gradients for different MPPT sampling frequencies, and efficiency values are provided for all cases. The results showed that a tracking speed of 2.5 Hz can be successfully implemented on a TEG system to provide ∼95% MPPT efficiency when the input temperature is changing at 5°C/s.

Supersonic reaction front propagation initiated by a hot spot in n-heptane/air mixture with multistage ignition

For large hydrocarbon fuels such as n-heptane, multistage ignition occurs at low initial temperature. Therefore, multiple pressure pulses produced by multistage ignition and complicated reaction–pressure wave interactions are expected to happen during autoignition and reaction front propagation initiated by a hot spot. In this study, 1D simulations are conducted for n-heptane/air mixture with three ignition stages respectively caused by low-, intermediate- and high-temperature chemistries. Multiple pressure waves, shock waves, and detonation waves are identified and they are found to be generated by heat release from different ignition stages and reaction–pressure wave interactions. The thermal states of flow particles at different initial locations are tracked and analyzed; and the mechanism for the development of multiple shock waves and detonation waves is discussed. With the change of temperature gradient inside the hot spot or the hot spot size, such interactions can be strengthened or weakened and thereby the mode of supersonic reaction front propagation changes. Furthermore, both planar and spherical configurations are considered and the curvature effects are examined. It is found that in spherical configuration, the pressure wave caused by intermediate-temperature ignition is not strong enough to induce a second detonation wave as that in planar configuration.

Abrupt changes in Indian summer monsoon strength during 33,800 to 5500 years B.P.

AbstractSpeleothem proxy records from northeastern (NE) India reflect seasonal changes in Indian summer monsoon strength as well as moisture source and transport paths. We have analyzed a new speleothem record from Mawmluh Cave, Meghalaya, India, in order to better understand these processes. The data show a strong wet phase 33,500–32,500 years B.P. followed by a weak/dry phase from 26,000 to 23,500 years B.P. and a very weak phase from 17,000 to 15,000 years B.P. The record suggests abrupt increase in strength during the Bølling‐Allerød and early Holocene periods and pronounced weakening during the Heinrich and Younger Dryas cold events. We infer that these changes in monsoon strength are driven by changes in temperature gradients which drive changes in winds and moisture transport into northeast India.

고품질 4H-SiC 단결정 성장을 위한 다공성 흑연 판의 역할

The present research is focused on the effect of porous graphite what is influenced on the 4H-SiC crystal growth by PVT method. We expect that it produces more C-rich and a change of temperature gradient for polytype stability of 4H-SiC crystal as adding the porous graphite in the growth cell. The SiC seeds and high purity SiC source materials were placed on opposite side in a sealed graphite crucible which was surrounded by graphite insulator. The growth temperature was around and the growth pressure was 10~30 Torr of an argon pressure with 5~15 % nitrogen. 2 inch off-axis 4H-SiC with C-face (000-1) was used as a seed material. The porous graphite plate was inserted on SiC powder source to produce a more C-rich for polytype stability of 4H-SiC crystal and uniform radial temperature gradient. While in case of the conventional crucible, various polytypes such as 6H-, 15R-SiC were observed on SiC wafers, only 4H-SiC polytype was observed on SiC wafers prepared in porous graphite inserted crucible. The defect level such as MP and EP density of SiC crystal grown in the conventional crucible was observed to be higher than that of porous graphite inserted crucible. The better crystal quality of SiC grown using porous graphite plate was also confirmed by rocking curve measurement and Raman spectra analysis.

Mid-Pliocene westerlies from PlioMIP simulations

The midlatitude westerlies are one of the major components of the global atmospheric circulation. They play an important role in midlatitude weather and climate, and are particularly significant in interpreting aeolian sediments. In this study, we analyzed the behavior and the possible mechanism involved in the change of the westerlies, mainly in terms of the jet stream position, in the mid-Pliocene warm period (3.3 to 3.0 million years ago) using simulations of 15 climate models from the Pliocene Model Intercomparison Project (PlioMIP). Compared to the reference period, the mid-Pliocene midlatitude westerlies generally shifted poleward (approximately 3.6° of latitude in the Northern Hemisphere and 1.9° of latitude in the Southern Hemisphere at 850 hPa level) with a dipole pattern. The dipole pattern of the tropospheric zonal wind anomalies was closely related to the change of the tropospheric meridional temperature gradient as a result of thermal structure adjustment. The poleward shift of the midlatitude westerly jet corresponded to the poleward shift of the mean meridional circulation. The sea surface temperatures and sea ice may have affected the simulated temperature structure and zonal winds, causing the spread of the westerly anomalies in the mid-Pliocene between the atmosphere-only and coupled atmosphere-ocean general circulation model simulations.

Interannual climate variability seen in the Pliocene Model Intercomparison Project

Abstract. Following reconstructions suggesting weakened temperature gradients along the Equator in the early Pliocene, there has been much speculation about Pliocene climate variability. A major advance for our knowledge about the later Pliocene has been the coordination of modelling efforts through the Pliocene Model Intercomparison Project (PlioMIP). Here the changes in interannual modes of sea surface temperature variability will be presented across PlioMIP. Previously, model ensembles have shown little consensus in the response of the El Niño–Southern Oscillation (ENSO) to imposed forcings – either for the past or future. The PlioMIP ensemble, however, shows surprising agreement, with eight models simulating reduced variability and only one model indicating no change. The Pliocene's robustly weaker ENSO also saw a shift to lower frequencies. Model ensembles focussed on a wide variety of forcing scenarios have not yet shown this level of coherency. Nonetheless, the PlioMIP ensemble does not show a robust response of either ENSO flavour or sea surface temperature variability in the tropical Indian and North Pacific oceans. Existing suggestions linking ENSO properties to to changes in zonal temperature gradient, seasonal cycle and the elevation of the Andes Mountains are investigated, yet prove insufficient to explain the consistent response. The reason for this surprisingly coherent signal warrants further investigation.

Research on Temperature Effects of the Pre-Stressed Concrete Box Girder Bridge

The distribution of the temperature gradient and temperature change of the pre-stressed concrete box girder are extremely complicated because of the multiplex environment. Temperature load has attached great importance in the field of engineering, and it has a great influence on the bridge’s structure, especially the box structure. The engineering background of this paper is a typical three-dimensional pre-stressed concrete continuous box girder bridge with variable cross section, comprising five spans in one continuous unit. Experiment on it and research the change rules of the temperature distribution, as well as the influence of the structure’s internal force resulted by temperature. Finite element software-Midas/FEA is used to model and calculate the bridge in order to analyze the temperature influence on structure’s stress in contrast to the measured data from the experiments

Dynamic behaviors of a molten carbonate fuel cell under a sudden shut-down scenario: The effects on temperature gradients

A three-dimensional (3-D), dynamic model of a molten carbonate fuel cell (MCFC) is developed in the current work. The model takes into account the heat and mass transfers of various reacting gas species. Yuh and Selman's model is implemented to solve the voltage–current relationship. In addition, water-gas shift (WGS) reaction is also included in the model. The simulation result is validated with published experimental data. The model is used to study the effects of steady and pulsating flows on the temperature gradients of MCFC electrodes in a shut-down event. Co-flow and counter-flow of MCFC are included in this study. The results show that higher thermal conductivity and smaller gas temperature difference before and after shut down event ensure better structural integrity of the fuel cell. In addition, under the simulated condition, the counter-flow operating condition is better for MCFC due to its overall lower temperature and also temperature gradients. In the case of the pulsating flow, the change of electrode temperature gradient is greater in co-flow MCFC compared to that of counter-flow MCFC. The sinusoidal profile of an electrode temperature gradient is more visible when both anode and cathode gas channels are subject to pulsation. A steady gas flow ensures a lower maximum temperature gradient in an electrode. Nevertheless, the simulation result also shows that under certain pulsating flow conditions, the cathode electrode will have a lower average temperature magnitude compared to that of steady-flow.

Heat balances and thermally driven lagoon‐ocean exchangeson a tropical coral reef system (Moorea, French Polynesia)

AbstractThe role of surface and advective heat fluxes on buoyancy‐driven circulation was examined within a tropical coral reef system. Measurements of local meteorological conditions as well as water temperature and velocity were made at six lagoon locations for 2 months during the austral summer. We found that temperature rather than salinity dominated buoyancy in this system. The data were used to calculate diurnally phase‐averaged thermal balances. A one‐dimensional momentum balance developed for a portion of the lagoon indicates that the diurnal heating pattern and consistent spatial gradients in surface heat fluxes create a baroclinic pressure gradient that is dynamically important in driving the observed circulation. The baroclinic and barotropic pressure gradients make up 90% of the momentum budget in part of the system; thus, when the baroclinic pressure gradient decreases 20% during the day due to changes in temperature gradient, this substantially changes the circulation, with different flow patterns occurring during night and day. Thermal balances computed across the entire lagoon show that the spatial heating patterns and resulting buoyancy‐driven circulation are important in maintaining a persistent advective export of heat from the lagoon and for enhancing ocean‐lagoon exchange.

Responses of the Western North Pacific Subtropical High to Global Warming under RCP4.5 and RCP8.5 Scenarios Projected by 33 CMIP5 Models: The Dominance of Tropical Indian Ocean–Tropical Western Pacific SST Gradient

Abstract Using the outputs of 33 coupled models that participated in phase 5 of the Coupled Model Intercomparison Project (CMIP5), the changes of the western North Pacific subtropical high (WNPSH) in the 2050–99 period under representative concentration pathway 4.5 and 8.5 (RCP4.5 and RCP8.5) scenarios relative to the 1950–99 period are analyzed. Under both scenarios, the projected changes in the WNPSH intensity are approximately zero in the multimodel ensemble mean (MME), and large intermodel spread is seen. About half of the models project an enhanced WNPSH and about half of the models project a weakened WNPSH under both scenarios. As revealed by both diagnostic studies and numerical simulations, the projected change in the WNPSH intensity is dominated by the change in the zonal sea surface temperature (SST) gradient between the tropical Indian Ocean (TIO) and the tropical western Pacific (TWP). A stronger (weaker) warming in the TIO is in favor of an enhanced (weakened) WNPSH, and a weaker (stronger) warming over the TWP is also in favor of an enhanced (weakened) WNPSH. The projected change of the WNPSH modulates the climate change over eastern China. Under both RCP4.5 and RCP8.5 scenarios, all of the models with a significantly increased (decreased) WNPSH intensity are associated with a significant increase in the precipitation over the northern (southern) part of eastern China and an enhanced (weakened) southerly wind.

Compositional diapirism as the origin of the low‐albedo terrain and vaporization at midlatitude on Ceres

AbstractRecent observations of Ceres, made using the Heterodyne Instrument for the Far Infrared on board the European Space Agency's Herschel Space Observatory, have shown that water vapor is emanated from the low‐albedo midlatitude regions. Based on the supposition that some dark spots on Europa may be caused by diapirism, we explored whether Ceres' environment also can induce compositional diapirism, and whether an upwelling diapir could explain the origin and distribution of the dark spots and vaporization of Ceres. If the density of the rock that constitutes Ceres is around 2700 kg m−3, the undifferentiated crust is stable over geological time periods at less than 180 K. At a surface temperature of 170 K, a diapir can reach the surface if the crust is a few tens of kilometers thick. Alternatively, if the surface temperature is 150 K, a large contrast in viscosity would prevent diapirs from reaching the surface. The relatively moderate surface temperature in the midlatitude regions of Ceres may be the reason for the formation of dark terrains occurring only in such areas. Our finite difference calculations do not show that diapirism melts the surface ice because the temperature gradient changes very little. However, if the observed vapor emission is caused by the sublimation of fresh ice, compositional diapirism could be the mechanism that transports the fresh ice to the surface. In addition to other mechanisms such as cryovolcanism, diapirism is a valid hypothesis for explaining the dark terrain and vapor emissions of Ceres.

Performance of August–September Indian monsoon rainfall when June–July rainfall is reported as being in deficit/excess

The Indian summer monsoon season (June to September) has been divided into two sub-seasons, viz., June + July (JJ) and August + September (AS). The performance of all-India AS rainfall has been examined when JJ rainfall is reported as being in excess/deficit, during the period 1871–2012. The study shows that the performance of AS rainfall is higher/lower than the JJ rainfall when JJ rainfall is in deficit/excess. The mean values of JJ and AS rainfalls are computed when JJ rainfall is in deficit/excess. The difference between the mean values is statistically significant. Sea surface temperature (SST) data over the Arabian Sea and Bay of Bengal for the period 1941–2011 have been used to examine the relationship between JJ SST and JJ, AS and AS − JJ (AS minus JJ) rainfalls. A statistically significant negative correlation is observed between JJ SST and JJ rainfall while significant positive correlation is observed between JJ SST and AS − JJ rainfall. The sub-seasonal relationship has been explained through the changes in the surface meridional temperature gradient over the Indian land and Oceanic regions in the JJ sub-season due to the performance of rainfall during the JJ sub-season. Wind data at 850 and 200 hPa levels for the period 1949–2012 have been analyzed to examine anomalies during deficit and excess JJ years. During deficit JJ rainfall years, easterly wind anomalies are observed at lower tropospheric levels over the Arabian Sea, which influence SST distributions. The SST distribution strengthens the meridional temperature gradient for developing the strong monsoon circulation during the AS sub-season thereby increasing the AS rainfall. A reverse situation is observed during excess JJ sub-seasons.

Present-day concepts of atmospheric frontogenesis. Part 2. Some results of computation from the real data

Reviewed are the recently published results of vector frontogenesis computation from the real and model data for a number of case studies. The results revealed that the development of troughs and ridges in upper-level frontal zones, jet stream meandering and intensification, cyclonic eddy generation and evolution are due to the specific distribution of frontogenesis. Main quantitative characteristics of vector frontogenesis are its components along and across the potential temperature contour and at the isobaric surface. The first component describes the frontogenetic effect of isotherm rotation and is called the rotational frontogenesis; the second component represents a measure of the change in the horizontal temperature gradient and is called the scalar frontogenesis. Frontogenesis characteristics are used not only as informative diagnostic parameters but also as the indicators of the future transformation of atmospheric fields. Presented are preliminary results of frontogenesis computation for a case of the high-amplitude wave in the upper-level frontal zone with the intense jet stream and deep stratospheric intrusion. It is demonstrated that the tropopause sinking on the cold side of the upper-level frontal zone is caused mainly by the scalar frontogenesis whereas the rotational frontogenesis plays a primary role in the area of the sharp rotation of isohypses causing the intensive rising of air on the warm side and the sinking on the cold side. The comparison of computations based on the objective analysis and global semi-Lagrangian atmospheric model output data, demonstrates that the jet streams, tropopause topography, and frontogenesis effect distribution are simulated correctly from the qualitative point of view while the forecasting fields are significantly smoothed in terms of numbers.

Eocene–Oligocene latitudinal climate gradients in North America inferred from stable isotope ratios in perissodactyl tooth enamel

The Eocene–Oligocene transition (~34Ma) was one of the most pronounced episodes of climate change of the Cenozoic. In order to investigate this episode of global climate cooling in North America, we analyzed the carbon and oxygen stable isotope composition of the carbonate component of 19 perissodactyl (horse and rhino) tooth enamel samples from the Eocene–Oligocene rocks of the Cypress Hills Formation (southwestern Saskatchewan, Canada); we then compared the results with previously published data from the US Great Plains (Nebraska, South Dakota, and Wyoming).Average (±1σ) perissodactyl enamel δ13C values (vs. V-PDB) in the Eocene (−8.8±0.3‰) and Oligocene (−9.0±0.3‰) are indistinguishable, suggesting no major change in mean annual precipitation in Saskatchewan across the transition. The δ13C values in Saskatchewan indicate the presence of arid ecosystems and are slightly higher than those in the US Great Plains, suggesting drier conditions at higher latitudes. With respect to oxygen isotopes, average (±1σ) perissodactyl enamel δ18O values (vs. V-SMOW) in the Eocene (19.8±2.0‰) and Oligocene (20.1±3.6‰) are also indistinguishable, suggesting no change in the δ18O of meteoric precipitation across the transition in Saskatchewan. Enamel δ18O variability is much larger in the Oligocene vs. Eocene, indicating a large increase in temperature seasonality. This increase in enamel δ18O variability is much larger than that recorded in the US Great Plains, suggesting that higher latitudes are more sensitive to major episodes of climate change with respect to temperature seasonality. Finally, our data indicate no major change in the Oligocene vs. Eocene latitudinal gradient in local water δ18O in North America, which suggests no change in mean annual temperature gradients across the transition. This result supports the hypothesis that ascribes the climate change of the transition to a drop in atmospheric pCO2 because climate models show that this mechanism produces uniform cooling at mid-latitudes.

Role of Changes in Mean Temperatures versus Temperature Gradients in the Recent Widening of the Hadley Circulation

Abstract The Hadley circulation (HC) has widened in recent decades, and it widens as the climate warms in simulations. But the mechanisms responsible for the widening remain unclear, and the widening in simulations is generally smaller than observed. To identify mechanisms responsible for the HC widening and for model–observation discrepancies, this study analyzes how interannual variations of tropical-mean temperatures and meridional temperature gradients influence the HC width. Changes in mean temperatures are part of any global warming signal, whereas changes in temperature gradients are primarily associated with ENSO. Within this study, 6 reanalysis datasets, 22 Atmospheric Modeling Intercomparison Project (AMIP) simulations, and 11 historical simulations from phase 5 of the Climate Modeling Intercomparison Project (CMIP5) are analyzed, covering the years 1979–2012. It is found that the HC widens as mean temperatures increase or as temperature gradients weaken in most reanalyses and climate models. On average, climate models exhibit a smaller sensitivity of HC width to changes in mean temperatures and temperature gradients than do reanalyses. However, the sensitivities differ substantially among reanalyses, rendering the HC response to mean temperatures in climate models not statistically different from that in reanalyses. While global-mean temperatures did not increase substantially between 1997 and 2012, the HC continued to widen in most reanalyses. The analysis here suggests that the HC widening from 1979 to 1997 is primarily the result of global warming, whereas the widening of the HC from 1997 to 2012 is associated with increased midlatitude temperatures and hence reduced temperature gradients during this period.

Effect of auxiliary TIG arc on formation and microstructures of aluminum alloy/stainless steel joints made by MIG welding-brazing process

A new hybrid welding process was successfully used to join aluminum alloy and stainless steel. In the MIG welding-brazing process, the lower thermal conductivity of steel can cause dramatic change of temperature gradient on steel surface, while the auxiliary TIG arc can change this phenomenon by heating the steel side. The auxiliary TIG improved the wettability of molten metal, resulting in the molten metal spreading fully on upper surfaces, front and back surface of steel, forming a sound brazing joint; the content of Cr and Ni elements in IMCs layer was increased, which can enhance the quality of the layer; and the microstructure of IMCs layer also was improved, increasing the bonding strength with the weld seam. The average tensile strength of the joint obtained with auxiliary TIG arc (146.7 MPa) was higher than that without auxiliary TIG arc (96.7 MPa).