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Fig. 1. About half of the surveys’ respondents worked at metalcasting facilities with 50 or fewer employees.


people, though 22% of all surveyed have made use of these ingots in the past. Other addition techniques mentioned but not used as often included: continuous additions with scrolling TiBor wire, TiBor “waffle” additions, grain refin- ing fluxes or pills, and use of a combined strontium plus titanium master alloy. Of those surveyed, 7% said they did not grain refine at all.


How do you test for grain refinement effectiveness?


Multiple methods exist that help the metalcaster deter- mine whether the refiner additions have had an effect on the alloy. Tese range from direct testing of mechanical proper- ties, to indirect spectrographic analysis that look for titanium or boron content within the alloy. Of the methods available, spectrographic analysis of titanium is used by 54% of those surveyed, followed closely by testing of mechanical proper- ties at 43.5%. Te larger facilities surveyed (greater than 250 employees) tend to test for effectiveness via multiple meth- ods, with 60% using three or more methods compared to only 20% in plants with less than 250 employees. Addition- ally, larger metalcasting facilities focus on the use of metal- lography, thermal analysis, and the “hockey puck” technique while smaller plants will more readily use spectroscopy, go by mechanical properties, or do no testing at all (22%).


In most cases, when do you add grain refiner relative to other


additives? Te addition of a grain refiner relative to other additives


was seen to be quite process dependent, with many responses showing a variety of timelines. Half (50%) of those sur- veyed said they added grain refiner at the same time or after additions of both magnesium and strontium, while the rest offered some variation of before “X” but after “Y” as seen in Figure 2. “Other” responses to this question included mak- ing additions 15 minutes into the degassing cycle, continu- ous additions by hand rather than coil, using only refining pills, and making additions to the ladle at the time of pour.


44 | MODERN CASTING November 2016


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