Structure using rock wool pad for replacement of riser exhaust needle to save molten steel

Abstract

The invention discloses a structure using a rock wool pad for replacement of a riser exhaust needle to save molten steel. A riser generally is provided with an exhaust needle for exhaust during mold filling, taking a turbosuperchager volute casing and exhaust manifold one-piece casting as an example, 0.025kg of the molten steel is consumed only by exhaust needle mold filling, two pieces are castedin one mold, each piece comprises four risers, and consumes 0.2kg of heat-resistant steel, yield is declined, and an exhaust needle mold and an exhaust needle molding are additionally arranged. A rock wool layer is pasted at the riser, the exhaust needle is eliminated, the casting yield is improved, and the molding process is simplified.

Description

technical field [0001] In the casting process, the exhaust pin on the top of the riser used for feeding is replaced by rock wool to save molten steel. Background technique [0002] In the casting process of the volute and exhaust manifold of the engine turbocharger, due to the extremely uneven wall thickness of the volute and exhaust manifold, there is a large difference between each other, and the cooling speed of each part is also very different. The molten steel in the thick part is often pulled away by the super-cooling and contraction of the thin wall, forming shrinkage cavities or porosity in the thick wall. Generally, risers are provided for the parts prone to shrinkage or porosity, such as volute and exhaust manifold. Due to the large volume of the riser, the flange cools slowly, which can supplement the molten steel to the shrinkage cavity, so that the shrinkage cavity will not be loose at the wall thickness. Most of the risers are designed to be cylindrical. When ...

AI Technical Summary

Problems solved by technology

Most of the risers are designed to be cylindrical. When molten steel fills the mold from the bottom of the riser, the gas inside the riser will be squeezed upward to form a high-pressure area, which will not be discharged from the gap between the sand grains, which will affect the filling of the riser. Usually, an exhaust needle is installed on the top of the riser to help the exhaust. If the riser air needle is installed, the consumption of molten steel will be increased. For example, there are 4 flanges in the exhaust manifold, and each flange is equipped with a riser and an exhaust needle. It will further reduce the yield of castings

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