may be 75RHN
it is 90
The Rockwell C Hardness for a grade 10.9 fastener is 32 - 39HRC or 320 - 380Hv10
59RC
28 - 32 hrc
the answer is 10KGF
7
it is 90
The initial load in Rockwell hardness test is 10KGf.
The Brinell hardness number of brass typically ranges from 80 to 100 HB. This hardness can vary depending on the exact composition of the brass alloy and any heat treatment it has undergone.
hardness as it is measured on a rockwell or brinell testing instrument
Rockwell hardness
The Rockwell C Hardness for a grade 10.9 fastener is 32 - 39HRC or 320 - 380Hv10
Both are two different scales of hardness measurement.
Rc is an abbreviation for the Rockwell Hardness Scale, used to determine the harness of materials.
for soft brass it is 60
plan a fair test with timing......... bash each rock with a hammer and see which one breaks first
59RC