Abstract
In recent years, the use of lightweight aluminum auto-parts is accelerating to improve fuel consumption. In particular, cylinder blocks have shifted to use aluminum, and the demand for the quality has been higher than before because of higher engine performance. As the manufacturing method, die-casting has been widely used to moderate the material cost increase. Die-casting is superior in cost performance and productivity, while, the high-speed molten metal flow tends to cause gas entrapment. Due to the complex molten metal filling pattern in die-casting, it is difficult to predict the gas entrapment even in CAE. To obtain high quality die-casting products, it is crucial to neutralize gas entrapment. For its evaluation, flow visualization system utilizing X-ray and non-contact molten metal sensor utilizing eddy current were developed. Effect of the casting condition on product defects was clarified by observing the actual molten metal behaviour and gas entrapment. In this study, the gas entrapment state was investigated along each filling process (sleeve, runner, and cavity). The optimized casting condition was proposed based on the measured results and consideration, and its benefit was confirmed.
Keyword: Die-casting, Cylinder block, Porosity, Visualization, Molten metal flow