In terms of fundamental properties, there are two product families, the “S” grades and “R” grades. The S grades are standard iron grades with a purity level of approximately 97.5%. The impurity is comprised of carbon, oxygen and nitrogen and is the cause of the iron particle’s unique onionskin structure.
R grades are higher purity iron grades with an average purity of 99.5%. Through a hydrogen reduction process, most of the residual carbon and nitrogen have been removed from the iron particle, producing a higher purity iron grade that is lower in durometer hardness and lacking the unique onionskin structure.