What is the difference between grade 60 and grade 40 steel bars?

Grade 60 has a tensile stress of 60000 psi while Grade 40 has 40000.

Grade 60 steel rusts faster than grade 40.

grade 60 bar can be identified by the Word 60 which should have printed on that while on grade 40 no no will be printed or written and we can identify this by counting the lines on steel as well.

If there are 3 lines longitudinally on the bar its is of 60 grade and if 2 lines longitudinally it will be identified as 40 grade.