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 into a 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, in particular to a mold shell roasting method for sequential solidification of precision castings. Background technique: [0002] The shell roasting method of the existing precision steel casting is: the shell is kept at the roasting temperature for a period of time, taken out and placed on the pouring site, and poured into the shell with molten metal. During pouring, the shell temperature is about 450°C-800°C, and the temperature distribution of the shell gradually decreases from the inside to the outside. For a relatively compact casting with an inner cavity structure, the temperature of the inner cavity of the shell is 200-400°C higher than that of the outer wall, and the feeding casting The riser is located on the outside of the shell. From the perspective of casting high-quality castings, the increasing temperature distribution from the inside to the outside after pouring is benefic...

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