Properties Of Submerged Arc Brazing Slag And Its Effect On Brazing Process Of Tin-based Babbitt

Babbitt is a kind of wear-resistant materials widely used in marine,nuclear equipment.Submerged arc brazing has an irreplaceable advantage in the preparation of babbitt.Through the analysis and research on the microstructure and properties of slag,and the influence of the slag on the brazing process,this paper exploring the mechanism of the submerged arc brazing process and promoting the engineering application of submerged arc brazing.At the same time,it enriches the research on the theory of welding slag.B₂O₃-Si O₂-Al₂O₃-Ca O slag system was designed for submerged arc brazing of babbitt.Based on the theory of ion-molecule coexistence and thermodynamic data,a calculation model of slag was established.The influence of basicity on the activity of components was analyzed using MATLAB.The microstructure of the flux and slag was investigated by X-ray photoelectron spectroscopy?XPS?and Fourier transform infrared spectroscopy?FTIR?.It is found that the amount of bridge oxygen structure increases and the[BO₃]structure increases in slag during the brazing process.One part of[BO₄]combined with the silicon oxygen network structure,forming the Si-O-B bridged oxygen structure,and the other part transformed into[BO₃]structure.The microstructure and composition of brazing babbitt were analyzed by scanning electron microscope?SEM?and X-ray diffraction?XRD?.Under the action of interface metallurgical reaction,the oxide film is removed the wetting and spreading process are promoted.Intermetallic compounds?IMC?grows into the side of babbitt on the brazing interface.The IMC in the interface of the submerged arc brazing babbitt is more plastic and the fracture mechanism is mixed fracture of toughness and brittleness.The slag stick on the surface of brazing babbitt when detachability decreased.The Laser confocal microscope?LSCM?and SEM was used to investigate the relative mechanism.When the granular crystal on the slag surface increases,the detachability decreased obviously.Based on the analysis of arc parameters and the temperature field,the influence of slag on the arc behavior was explored.During the process of submerged arc brazing,the arc burns stably and diffuses in the arc cavity.