Refractoriness/fusion points of ‘Superduty’ refractories is _______________ °C? August 26, 2021March 8, 2019 by admin Refractoriness/fusion points of ‘Superduty’ refractories is _______________ °C? A. 1520-1630 B. 1630-1670C. > 1730 D. > 2000