Rebar grade
A number indicating the steel's minimum yield strength in thousands of pounds per square inch. Grade 60 is the common structural default, with Grades 40, 75, 80, and 100 also produced.
What does rebar grade mean?
Higher grades allow less steel to carry the same force, but they change development and splice lengths, so substitution is an engineering decision rather than a purchasing one. Grade is rolled into the bar as marks that let an inspector verify material after delivery. Standard carbon-steel bar and weldable low-alloy bar can share a grade number while being different materials with different chemistry requirements.
In practice
An inspector reading the raised marks on delivered bar is confirming grade, size, mill, and material type against the drawings.