Statistical analysis of parameters of the process analysis of grain refinement of the aluminum cast alloy by Al–Ti–B and Al–La–B master alloys

Abstract

Current requirements of consumers to the level of properties of the cast parts require the compulsory realization of the operations of modification performed by the manufacturer. For the major part of aluminum alloys, the role of main inoculant is played by Al–Ti–B, which is susceptible to poisoning for high contents of Si. The present study is devoted to the comparative assessment of the effects of application of a traditional Al–5Ti–1.5B inoculant and a promising Al–3La–1.5B material performed by using AK12 silumin (an analog of AlSi 11) as an example. On the laboratory scale, a series of experiments was carried out for various combinations of concentration and time parameters, namely, the level of consumption varied from 0.5 up to 2 kg/ton, while the holding time of the melt varied within the range 20–60 min. By using the analysis of variance, we performed statistical processing of the results: the resulting models of response reliably explain more than 84% of changes. The predictive plots of the influence of modifying parameters on the grain size were constructed. The procedure of optimization of these parameters was carried out by the Harrington generalized desirability method. The data on the modification of AK12 alloy by introducing Al–3La–1.5B on the commercial scale are confirmed by the results of analysis of experimental castings obtained by the method of low-pressure casting.