Stainless Steel Casting Processing Character & notification:
Mechanical property of stainless steel casting is higher than iron casting, but the casting property of stainless steel casting is worse than iron casting, Because the melt point of stainless steel casting is higher, and steel liquid is easily be oxidized, flow of stainless steel liquid is not good, shrinkage is bigger.
Its body shrinkage is 10~14%, while its liner shrinkage is 1.8~2.5%, In order to prevent steel castings from pouring, cold insulation, shrinkage cavity and shrinkage ,crack and defects of grain, stainless steel casting processing must apply complex processing:
- Because the flow of stainless steel is not good, to prevent stainless steel castings having cold insulation, pouring shortage,the thickness of stainless steel can not be smaller than 8mm. The structure of pouring system is as simple as possible, and the section dimension should be bigger than iron cast, dry casting type or hot casting type can be applied, improve the pouring temperature appropriately, normally is 1520°～1600℃. Because pouring temperature is high, the steel water is over heated, and a long time in liquid situation, stainless steel flow can be improved. But big grain, hot cracks, stamo and sand etc defects will be resulted because of highly pouring temperature. So the general small type, thinner thickness and complex shaped casting, their pouring temperature is normally about steel’s melting temperature +150℃, and the pouring temperature of big type, thick castings will be 100℃ higher than its melting points.
- Because shrinkage of stainless steel precision casting is more bigger than iron castings, in order to prevent castings having shrinkage holes and shrinkage defects, in processing, stainless steel casting apply riser,cold iron and subsidies etc action to realized the orderly solidification.
And also, in order to prevent stainless steel castings having shrinkage holes, shrinkage, stamos and crack etc defects, stainless steel castings should be with uniform thickness, avoid sharp corner and perpendicular corner, add sawndust into the sands during pattern-making, add coke in core, and apply empty core and oil core etc to improve the concessibility and permeability of sand type or core.