Copper alloy metal mold sand covered centrifugal casting technology

Abstract

The invention discloses a copper alloy metal mold sand covered centrifugal casting technology. The technology comprises the following steps: during sand covering on a metal mold, firstly coating a paint of which the bonding property is better on the inner surface of the metal mold, wherein the paint is obtained through the following steps of uniformly mixing bentonite, 3%-5% of water glass and water, soaking the mixture for 24 hours and preparing the mixture so as to enable the density to be about 1.6 sand / m<3>; then regulating a wood model, of which the surface is coated with paraffin, in the central position of the metal mold; filling around the wood model with clay sand, while filling with the sand, filling with general clay coarse sand close to the metal mold, filling with general clay fine sand close to the wood model, and tamping a sand covered layer while filling, so that the sand layer is dense and uniform to the greatest extent; after taking out the wood model, coating a paint, wherein the paint is obtained through the following steps of uniformly mixing 95% of black lead powder and 5% of bentonite under a dry condition, and pouring hot water to the mixture, preparing the mixture so as to enable the density to be about 1.35g / cm<3>, and drying. Through the use of the technology, defects of dispersed shrinkage or rarefaction, segregation (tin sweat), dents in the inner wall of a casting and the like can be greatly overcome, and high-quality castings with high density and good properties can be produced.

Description

[0001] technical field [0002] The invention belongs to the technical field of alloy cast iron casting, and in particular relates to a sand-covered centrifugal casting process for copper alloy metal molds. [0003] Background technique [0004] Due to the good thermal conductivity of the metal mold, fast solidification speed of the alloy, fine grains, less segregation, and short solidification time, it is very common to use centrifugal casting copper alloys to obtain castings with dense structures such as sleeves, gears, and valves. The method is also relatively mature. However, this method usually processes a metal type for a casting of one specification, and the cost is very high. The metal type has a long processing cycle and is suitable for large-scale or large-scale production. It is not suitable for single-piece small-batch production castings, so The metal mold sand-coated centrifugal casting process can produce sleeves and gear copper alloy castings of differen...

AI Technical Summary

Problems solved by technology

However, this method usually processes a metal type for a casting of one specification, and the cost is very high. The metal type has a long processing cycle and is suitable for large-scale or large-scale production. It is not suitable for single-piece small-batch production castings, so The metal mold sand-coated centrifugal casting process can produce sleeves and gear copper alloy castings of different specifications. However, after the metal mold is covered with sand, it is equivalent to wearing a thick layer of thermal underwear on the metal mold, which hinders heat conduction. The holding time is increased, the solidification speed of liquid metal is reduced, and castings are prone to defects such as shrinkage or porosity, segregation, and pits. Therefore, it is necessary to study a set of more suitable metal mold sand-covered centrifugal casting methods to prevent castings from producing defects.