Casting causes cold insulation defect and its prevention methods
Release Time::2014-09-03
1 casting cold septal defect characteristics of metal liquid filling, in the transfer of liquid metal at the fusion is not good, but also through or notthrough the gap called cold shut in castings. In the casting surface away from the channel and thin wall. The shape of a liquid flow when the initialshape, one edge smooth, rounded. The 2 reason 1) due to the amountof molten metal is not, or because of running fire, causing castinginterrupt. 2) the metal liquid is blocked in the cavity flow. 3) alloy chemical composition is not appropriate, baked and low pouring temperature,oxidation of metal liquid is serious, poor liquidity. 4) pouring system design unreasonable, ingate position properly, section area is too small,a number of small. Sprue height is low, the liquid metal pressure head is not enough. 3 methods to prevent 1) by using the higher increase box or booster gate cups of liquid metal head. 2) and rational layout of the runner system, basal area increased ingate ingate, pouring positionincreased number or change the casting, the thin-walled surface easyfilling. 3) other operations to be careful, case but clips or pressure tank,mud type and the box surface, prevent running fire. The casting processshall not stop. 4) improve the sand permeability, set the appropriateoutlet riser, the gas cavity smoothly discharged. 5) in strict accordance with the melting operation, prevent the liquid metal oxidation, increasing the tapping temperature, increase the fluidity of molten metal.