The Researchment Wettability Of Iron-based Filler Metal And The Brazing Joints Performance For Stainless Steel Oil Cooler

Iron-based filler metal have high strength,high reliability,excellent wettability and low cost.Traditional pure copper and BNi-5 nickel-based filler metal are mostly used for Stainlness steel oil cooler,But pure copper filler metal is easy caused corrosion failure of the engine,brazing joints in the large clearance cracking and other issues,it is difficult to meet the requirements of the use of stainlness steel oil cooler.In this paper,the vacuum brazing of 06Cr19Ni10 stainless steel was carried Fe40CrNiSiP?Fe43CrNiSiMnMoB?Fe39CrNiCuPSi three iron-based filler metal.Melting element P,Si,B,Cu of new iron-based filler metal with element Fe,Cr,Ni form intermetallic compounds,affect the performance of brazed joints,order to obtain excellent performance of the brazed joints,The effects of three kinds of iron-based brazing filler metal on the surface of stainless steel and the properties of the joints under different gaps were studied.The effects of lower melting elements such as P,Si,B and Cu on the brazing performance were studied.for the stainless steel oil cooler in the actual production process to provide a theoretical basis.Results show that.(1)three kinds of iron-based filler metal can be wet stainless steel based material,spreading area and clearance filling: Fe39CrNiCuPSi>Fe40CrNiSiP>Fe43Cr-NiSiMnMoB,while the wetting angle and spreading area is just the opposite.Fe39 CrNiCuPSi and Fe40 CrNiSiP brazing filler metal in the form of reactive wetting wetting,and with B,Si element Fe43 CrNiSiMnMoB brazing filler metal paste casting type and with P,Si element solder has a significant difference,belonging to the dissolved drive wetting.(2)With the brazing clearance increasing,shearing strength of Fe39 CrNiCuPSi and Fe40 CrNiSiP brazing joints increases first and then decreases,when the brazing clearance width is 0?m,Because brazing filler metal can not completely fill the brazing seam so that the brazing joints shearing strength is lowed.When the braing clearance width is between 20 and 30?m,shear strength reaches maximum,And the brazing gap exceeds 150 ?m,the strength is almost constant,and the strength is 100 MPa.(3)In the brazing process,element Cu in the matrix Fe39 CrNiCuPSi filler metal is solid solution in the form of solid solution,the other part of the Cu is distributed in the center of the brazing seam in the granular form,and the B element is diffused through the intergranular infiltration The base metal grain boundary forms low melting eutectic.(4)Fe40CrNiSiP and Fe39 CrNiCuPSi two kinds of iron-based filler metal for product testing,due to the clearance between the chip and the chip is too large,Fe40 CrNiSiP iron-based filler metal brazing products in the test process all failed.Although using Fe39 Cr NiCuPSi brazing stainless steel products through the air tightness test and 5.5 MPa,due to local virtual welding in the process of pressure impulse test failure.