Rebar designation, metric 1

[Zhopping]

For metric rebar, the fourth digit stamped on the rebar is the grade, such as 40, 50, 60, 75. In metric how does this work? I believe that a "4" for the fourth digit means grade 60. How does this work? Thanks

 

[JAE]

According to a handy CRSI plastic pocket card I have, it indicates that the 4 stands for Grade 420 (420 mPa) which equals 60.9 ksi (i.e. 60 grade in English units). The 5 refers to Grade 520 (520 mPa) which equals 75.4 ksi.