Shell roasting method of precise steel casting progressive solidification

Abstract

The invention discloses a shell roasting method of precision steel casting progressive solidification, comprising the following steps of: firstly, roasting and tapping a shell with an inner cavity structure; next, after insulating materials are plugged into a hole which is arranged on the shell of an inner cavity part of a casting piece and is communicated with the outside, placing the shell intoa roasting furnace and heating, and taking out the shell after being heated for 15-30 minutes. The shell roasting method is used for heating the shell in a cold-interior and hot external mode, improves the sequence of solidifying processes of molten metal, roasts the shell for the same riser design, can eliminate the defect of the local shrinkage of the inner cavity of the casting piece and increases riser feeding efficiency.

Description

Technical field: [0001] The invention mainly relates to the field of precision casting, and in particular relates to a method for calcining a shell of a precision casting steel piece with sequential solidification. Background technique: [0002] The existing method for calcining the shell of the precision steel casting is as follows: the shell is kept at the roasting temperature for a period of time, taken out and placed on a pouring site, and molten metal is poured into the shell. The temperature of the mold shell is about 450℃-800℃ during pouring, and the temperature distribution of the mold shell gradually decreases from the inside to the outside. For a more compact casting with an inner cavity structure, the temperature of the inner cavity of the mold shell is 200-400℃ higher than that of the outer wall. The riser is located on the outside of the shell. From the perspective of casting high-quality castings, the temperature distribution increases from the inside to the o...

AI Technical Summary

Problems solved by technology

From the perspective of casting high-quality castings, the increasing temperature distribution from the inside to the outside after pouring is beneficial to the liquid metal in the riser to fully supplement the volume shrinkage of the casting when it solidifies, but the temperature distribution of the mold shell is opposite, which seriously weakens the riser. Feeding efficiency, resulting in local shrinkage defects in the inner cavity of the casting, the size of the riser must not be increased, but sometimes the increase in the size of the riser cannot eliminate the shrinkage defects