Analysis Of Dimension Stability About The Cavity And Stress Transformation In The Process Of Manufacturing Steel-based Mold By Thermal Spray

Because the process of spray depositing is successive, the real time measurement oftemperature and stress of the coatings' interior and interface is difficult. So it is necessary toestablish the transmit heat model to simulate the temperature field and stress field of coating.It has calculated the temperature field and stress field of one metal particle or coatings in theprocess of depositing on the matrix's surface by applying the transmit heat theory; establishedthe transmit heat model of the thin and fiat particle; used the theory and formula to deduce themetal particle's boundary conditions, such as initial temperature, etc.It has calculated the coating's temperature field and stress field by the large-sized FEMsoftware ANSYS; established the suitable FEM counting model; used the method of microsize layer superimposing layer by layer and indirect coupling, in other words, first to simulatethe coating's temperature field, then switch the element type to structural analysis element,use the calculation result data as the boundary load of the stress field's calculation. It has usedthe element live or death technology to active the succeeding element, realized transferableboundary to simulate the real coating's depositing process.It has obtained the coatings and matrix's temperature field. The result shows that it existmaximal temperature gradient on the interface between coating and matrix when the spraywas just finished. The former coatings and the matrix's interface keep a relative stabletemperature, but the upper coatings'temperature is higher. With the increasing time of cooling,the temperature of upper and lower coatings prone to concordance.The dangerous stage of the coating being destroyed is the early stage of spraying. Thecoating's critical bending stress is rising as its thickness increasing. The destabilization's generating will be more and more difficult. After the first minute coating was deposited on thesurface of matrix, its maximum shrinkage stress less than the critical warping stress, so it willnot be destroyed. The maximum stress of the coatings mainly distribute at its lower sidecontacting with matrix, secondary at its central position. The stress field of the coating'scentral position out diffusion as round waves, and the stress value has the trend of increment.At the coating's lower side surface, special at the brim, the von misses stress is maximal. Thedirection of tensile stress at the coating's brim position is oblique up to the model's centerposition, and this is the main cause of the coatings separating itself from the matrix and itswarping.The whole coating's shrinkage directs to center and the shrinkage value is increasingfrom center to brim. The coating's shrinkage is small. Utilizing the martensitic stainless steel'sphase transition action, the calculated result shows that the dimensional discrepancy of arcspraying mold's cavity is only 0.018ï¼…, and it is accordance with the dimension of real timemeasurement.