The spheroidal graphite irons, aka ductile irons and nodular irons are the strongest. There are several governing specifications from the various standardization groups that describe this material, but it is common to refer to the grades by yield strength and elongation. One common generic name is "5506", which means 55,000 psi min. yield and 6% min. elongation. There are as cast grades, heat treated grades and austenitic corrosion/heat resisting grades.
ASTM A536 ductile iron for castings. The grades are named based on material properties. If you see "65-45-12" that is tensile strength - yield strength - %elongation. Depending on the heat treat, you can get a very strong material (120-90-02 !) but it won't be very tough. 65-45-12 is a common grade, it can be "as cast" with no heat treat required, and is in the ballpark of A216 WCB steel for material properties.
I am guessing the 5506 mentioned above is plate, cast equivalent for those material properties "90-55-06."
In U.S.automotive circles, it is common to drop the tensile and just refer to the grade by the yield and elongation. Thus, "90-55-06" is equivalent to "5506". That is how the material is described in SAE J434.
Thank you guys for the responses
I was searching in matweb about the material J434.. I got the results for UNS F33100 Cast Iron/ 65-45-12/ SAE J434 D4512
among the above three which is Standard nomenclature?
