The reducer housing is in 482x446x434mm and 7.0mm wall thickess.The casting have some big and thick stud,which easily cause shrinkage porosity and air pores.The airtightness test need to be done at 0.6MPa.
The key area do not allow any kind of welding.Therefore,some processing are used for final quality of castings.The sprue provide enough feeding capacity.Meanwhile,some chill can improve the feeding capacity as well.
By optimization,the solidification of difference area will be in order.The feeding capacity will be improved.It solve the problem that there is not enough feeding capacity from bottom to top in low pressure die casting.The chill also help the casting to have nice density.
By simulation,the whole filling process is stable and smooth.But there is still some shrinkage porosity defect happed to key area.To solve the problem,the sprue need to be enlarged and some chill will be placed onto key areas.
By this kind of modification,the filling speed still be 50mm/s and pouring temperature is 725℃.There is no shrinkage porosity at all.
- By X-ray test,there is no shrinkage porosity inside casting.
- By measuring test,all size are qualified.
- The segment of casting have been done mechanical strength testing.The result is on average 340MPa tensile strength,290Mpa Yield strength,6% elongation.
Therefore,the sprue shape sometimes need to match geometry of castings.The optimization is based on simulation in order to get final qualified castings.