摘要
根据描述弯曲液面上任一点处液面内外压强差的Ｙｏｕｎｇ－Ｌａｐｌａｃｅ方程，从液态金属在重力和表面张力作用下的平衡条件出发，并基于二维假设，建立了描述熔敷金属表面形状的静态平衡模型。以由三相接触线平衡条件确定的接触角θ和单位长度上熔敷金属体积为边界条件，采用迭代算法求解Ｙｏｕｎｇ－Ｌａｐｌａｃｅ方程，得出了平板表面上的熔敷金属平衡形状。在此基础上，考虑熔池几何形状的影响，建立了平板堆焊时咬边产生机理的静力学模型，应用双重迭代算法对该模型进行求解，可以得出熔敷液体金属与熔化母材共同达到平衡时的条件。采用该模型计算的产生咬边的临界条件与实验结果吻合得很好，最后，应用该模型对平板堆焊时影响焊缝咬边的因素进行了计算与讨论。计算结果指出，增大材料润湿性，减小熔宽，增大单位长度上的熔敷金属量是减小咬边倾向的途径。
On the basis of the equilibrium conditions between gravity force and surface tension exerted on liquid metal, a static model is established to describe the surface shape of the deposited metal, the foundation of the model is the Young-Laplace Equation, which describes the pressure difference between the two sides of a curved liquid surface. Two dimensional hypothesis is adopted to simplify the calculation. The contact angle θ and the volume of filler metal on unit bead length are taken as two boundary conditions, so that the surface shape of the molten metal on a plane can be solved by an iteration algorithm. Then a static equilibrium model of the mechanism of the undercut phenomenon in high speed bead on plate welding is established, in which the geometry of the molten pool is considered. A‘double iteration algorithm' is applied to get the equilibrium condition for the mixture of the filler metal and the molten base metal. The critical undercut condition calculated by this model corresponds well with the experimental result. Finally, the model is applied in analyzing the factors that act upon the undercut tendency. The analysis shows that by improving the wettability of the material, decreasing the bead width and increasing the volume of filler metal on unit bead length, the undercut tendency can be decreased.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
1999年第1期16-21,共6页
Transactions of The China Welding Institution
基金
北京市自然科学基金
