板式铝合金轮辋铸造针孔缺陷分析

An Analysis of Pinhole Defects of Aluminium Alloy Disc-type Rim when Cast

铝合金液在冷却和凝固过程中,由于溶解度降低,使溶解在铝合金液中的气体析出,气泡在上浮析出过程中若遇到型芯的阻挡,或由于冷却过程中合金液的粘度不断增高而不能上浮,就会在轮辋上形成针孔。有关资料介绍:当铝合金液中含氢量超过0.001％时,轮辋表面就会形成针孔。为防止针孔产生,可从3个方面解决:即减少外界氢气来源、控制铝合金液的吸气能力及铝合金液的除气处理。

In the process of cooling and solidification of aluminium alloy liquid,gas dissolved in the liquid may separate out due to low solubility.If the air bubble is blocked by the core when it floats up, or the air bubble fails to go up due to higher viscosity of the alloy liquid,pinholes would appear on the rim. It is reported thar when the hydrogen content in the aluminium alloy liquid is over 0.001%,pinholos will be seen on the rim surface.In order to get the case avoided,the following ways are recommended to take up,l.reduce hydrogen from outside,2.control the ability of air suction of the aluminium liquid,3.remove the gas from the liquid.