Perhaps the biggest problem that you’ve encountered in your attempt of producing stainless steel investment castings is shrinkage. Although these defects are invisible to the naked eye, these shrinking defects can be detected after post machining. The poor shrinkage of molten skill can be attributed to several factors, namely:
The Sprue Gate’s Effect
If a thin plane between two thick ones is present and the three surfaces aren’t in the same plane, you can place two sprue gates on the two thick planes in order to increase the molten steel. The shrinkage effect will occur at the intersection of the thin and thick planes if only one gate is placed. However, if your customer agrees to thicken the thin plane, only one gate can be placed.
The Gating System’s Effect
You can use the gating system with a large cross-sectional area when no huge difference between the sprue gate’s thickness and the thickness of the stainless-steel investment castings. Unlike the small gating system. The larger gating system can facilitate feeding through its slow cooling feature.
The Stainless-Steel Casting Structure’s Effect
There are times when the shrinkage defects are found away from the gate. This usually occurs when the structure of the stainless-steel investment castings are more complex due to the molten steel’s insufficient packing between the gate and the shrinkage area.
The Pouring Temperature’s Effect
The appropriate increase of the pouring temperature can significantly reduce the shrinkage effect when only a slight shrinkage is detected on stainless steel investment castings. The slower the pouring speed, the more the shrinkage is reduced under the premise of ensuring that the casting isn’t deficient in terms of content.
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