Method for improving heat insulation effect of open riser

Abstract

The invention relates to a method for improving the heat insulation effect of an open riser, which is characterized in that after completing pouring castings, an insulation board covers the top of the open riser, according to the dimension of the open riser, the insulation board is a square case which is made of 5-12mm thick steel boards and is adaptive to the dimension of the open riser, the square case is filled with aluminium silicate Al2O3.3SiO2 and is compressed, the upper part of the square case is welded by an iron supporting and tensioning net with diameter of 10-14mm and the square case is fixed on the open riser. The method has the following beneficial effects: the cover board aims to prevent deformation under high temperature and play a role of good heat insulation; the insulation board is simple and convenient to operate and can be recycled; and after the insulation board covers the top of the open riser, the insulation board can well reduce radiation and convective heat transfer, reduce the heat dissipation speed of the molten steel, lengthen the solidification time, improve the feeding effect of the riser, effectively eliminate the shrinkage cavity and ensure the quality of the castings.

Description

technical field [0001] The invention belongs to the technical field of casting, and relates to a method for effectively eliminating shrinkage cavities, ensuring the quality of castings and improving the thermal insulation effect of open risers. Background technique [0002] The risers of steel castings can be divided into two types: open risers and dark risers. The open riser can observe the rise of molten steel, and it is convenient to sprinkle heating agent and heat preservation agent on the top of the riser. In order to achieve a better feeding effect, the riser can be replenished and spot poured. But the open riser also has shortcomings: when exposed to the air, heat convection and heat radiation occur on the top surface of the riser, which is carried out by radiation heat transfer of high-temperature molten steel and convective heat transfer between surface molten steel and air; riser convective heat transfer The driving force is the temperature difference between the ...

AI Technical Summary

Problems solved by technology

But the open riser also has shortcomings: when exposed to the air, heat convection and heat radiation occur on the top surface of the riser, which is carried out by radiation heat transfer of high-temperature molten steel and convective heat transfer between surface molten steel and air; riser convective heat transfer The driving force is the temperature difference between the molten steel and the air. The air heated by the molten steel continues to rise, and the cold air is continuously replenished to form air convection. A large amount of heat energy in the molten steel is taken away by the convective air.

After pouring for a period of time, the top of the riser will quickly crust, which isolates the molten metal in the riser from the atmosphere and becomes a "self-weight riser", which reduces the feeding efficiency of the riser