In present work, flux assisted-tungsten inert gas (FA-TIG) welding of bimetallic P92 martensitic steel-304H austenitic stainless steel (ASS) is carried out using SiO₂–TiO₂ binary flux. Seven binary fluxes were prepared by varying the proportions of flux powders (SiO₂ and TiO₂) and the effect of flux composition on weld bead cross-section was studied. The experimental results indicated that binary flux (flux B) with composition 90% SiO₂ + 10% TiO₂ yields the most pronounced effect on weld bead cross-section with 289.9% improvement in the depth of penetration (DoP) and 58.48% reduction in weld width (WW) in comparison to TIG (no flux) weld joint. To understand the potential mechanisms (arc constriction and reversal of Marangoni's convection) account for improved weld bead cross-section, the efficacy of flux compositions on welding arc/pool behavior is discussed in detail. The addition of a little quantity of TiO₂ (10%) in SiO₂ (90%) flux helped in achieving the narrowest arc (arc diameter: 5.40 mm), the maximum increase in arc voltage (ΔV = 2.14 V) and an increase in nascent oxygen amount (151 ppm) in the weld pool as compared to TIG (no flux) welding, which confirmed the occurrence of both arc constriction and reversal of Marangoni's convection. The weld joint developed using optimized binary flux (flux B) possessed untempered lath martensite, prior austenite grain boundaries, ferrite stringers and equiaxed austenite grains in the various zones of the weld joint. The average hardness of the weld zone was obtained as 415.9 HV. The developed weld joint qualified the tensile test with ultimate tensile strength (UTS) 680.9 MPa, yield strength (YS) 340.5 MPa and elongation 31.4%.

在目前的工作中，使用SiO ₂ -TiO ₂二元焊剂对双金属P92马氏体钢-304H奥氏体不锈钢（ASS）进行助焊剂辅助钨极惰性气体保护（FA-TIG）焊接。通过改变助熔剂粉末（SiO ₂和TiO ₂）的比例制备了七种二元助熔剂，并研究了助熔剂组成对焊缝横截面的影响。实验结果表明，组成为90％SiO ₂  + 10％TiO _2的二元助熔剂（助熔剂B）与TIG（无助焊剂）焊接接头相比，对焊缝横截面产生最明显的影响，熔深（DoP）提高了289.9％，焊接宽度（WW）降低了58.48％。为了了解改善焊缝横截面的潜在机理（弧形收缩和马朗戈尼对流的逆转），对焊剂成分对焊接电弧/熔池行为的有效性进行了详细讨论。在SiO _2中添加少量的TiO ₂（10％）与TIG相比，（90％）助焊剂有助于实现最窄的电弧（电弧直径：5.40 mm），最大电弧电压增加（ΔV= 2.14 V）和初生氧气量（151 ppm）的增加（无焊剂）焊接，这证实了电弧收缩和Marangoni对流的反转。使用优化的二元焊剂（焊剂B）开发的焊接接头在焊接接头的各个区域中具有未回火的板条马氏体，先前的奥氏体晶界，铁素体桁条和等轴奥氏体晶粒。焊接区的平均硬度为415.9 HV。开发的焊接接头通过了极限拉伸强度（UTS）680.9 MPa，屈服强度（YS）340.5 MPa和延伸率31.4％的拉伸试验。