铸钢件热裂ppt课件

(1)HOTTEARS热裂,Thecrackisinahotspot,nearaningateorriser,oraheavysection;anditisveryvisibleaftershakeout裂纹一般在热结，靠近内浇道或冒口，或者比较重的部位。落砂后很容易看到。,1,Thejaggedanddiscontinuoussurfaceappearanceofahottearonthesurface表面热裂的不平整的弯曲的外观,2,Hot-Tear,CrackMorphology:热裂形态：Surface:Wideanddiscontinuous(jagged)表面：宽的，间断不齐的Face:Verydark(oxidized)andfeaturingdendriticregions外观：暗（氧化），树状形态X-section:darklyoxidized,deep,wide,discontinuous,linedwithsilicates横截面：氧化、深、宽、间断、硅酸盐排列,3,CrossSectionofHotTear热裂横截面,4,Hot-TearCauses热裂原因,Hinderedcontractionduringthelatterstagesofsolidification凝固后期的受阻收缩Casting/riggingdesignfeatures:opposingflangesorappendages,gatingsystemrunners铸件设计特征：与凸缘或附件相反，横道进入系统Hotspotorlargethermalgradient热结或大的热梯度isolatedheavysection,orheatconcentrationataningateorrisercontact单独的重的部位，或者内浇道、冒口的热集中区域Constrictionstresscausedbymoldorcore模具或芯盒的收缩力Excessmold/corestrengthorsanddensity额外的模具/芯盒力或砂密度Lowmelt-pointphasesintheinter-dendriticregions内部树状结构中的低融化点Usuallyduetohighsulfur,ortypeIIsulfideinclusions一般因为高S，或二类硫化物杂质Highpouringtemperatures高温浇注,5,Hot-TearCures解决方案,Identifysourceofstressandeliminateit:找到压力源并消除Stressisinadirectionacrossthedirectionofthetear压力在裂纹的交叉方向Changerunnerconfiguration改变横道Reducemold/coreconstriction减小模型/砂芯收缩Ram-uplightnerpocketsinmold,hollowourcore,providecoremandrel,etc模具中堵上口袋，芯盒变空，提供芯盒轴等Reducebinderlevel减少粘合剂Reducesandcompaction减小型砂紧实度Reducehotspot减小热结Changeingatelocation改变内浇道位置Usemultipleingates用多个内浇道Lowerpouringtemperature低浇注温度Providechill提供冷却Reducesulfurle