Original gravel additive for preventing castings stria defect

Abstract

The invention discloses a raw sand additive for preventing casting rattail defect, including following weight compositions: transparent quartz 8%, calcite 1%, sepiolite 1%, kaolinite 70%, pyrophyllite 10%, magnetite 10%; without affecting functional performance of mixture and sand mould, and mainly preventing casting rattail defect, while with assistant curative effect for the casting air-hole and the burnt-on sand (sintering) and so on defects.

Description

technical field [0001] The invention relates to a raw sand additive for preventing casting vein defect. Background technique [0002] Veining is a common casting defect in sand casting, especially resin sand casting, that is, irregular shaped metal protrusions appearing on the rounded corners, planes and high-temperature hot spots on the casting surface. Veining, especially in the inner cavity of complex castings such as engines and valves, is not only difficult to clean, but also affects the cleanliness of castings and the flow of coolant, thereby reducing product performance indicators. [0003] Solving and preventing the occurrence of veining has always been an important topic in the research of the foundry industry. Before the 1960s, foundry workers mostly used 30-50% special sand with low expansion rate, such as zircon sand, chromite sand, etc., to solve the veining problem, but this method affects the mixing The fluidity of the material will accelerate the wear of th...

AI Technical Summary

Problems solved by technology

Before the 1960s, foundry workers mostly used 30-50% special sand with low expansion rate, such as zircon sand, chromite sand, etc., to solve the veining problem, but this method affects the mixing The fluidity of the material, the large capacity accelerates the wear of the core box, the unit cost is high, and the anti-veining effect is average

Later, sawdust and starch-based organic composite materials were used, but the loss on ignition of this organic composite material was as high as 40-50%, and the usable time of the mixture and the strength of the sand core were seriously reduced, the pass rate of the sand core dropped sharply, and the pores of the casting , sticky sand defects increased sharply