Why is the earthing device forbidden to use thread steel instead of round steel as lap steel bar?
The mechanical strength of the steel thread is destroyed. Because the supporting point is only the ground, it is easy to cut the steel directly if the thread is not vertical. Therefore, we need to use angle iron, steel pipe or smooth steel round bar.
H, R, and B are the first letters in English for hot-rolled (Hotrolled), ribbed (Ribbed) and reinforced (Bars) three words. Hot rolled ribbed bar is divided into two levels, HRB335 (old No. 20MnSi), three HRB400 (20MnSiV, 20MnSiNb, old No. 20Mnti), four grade HRB500 three grade.
Steel is known as hot rolled ribbed bar. Ordinary hot rolled steel bars are made up of HRB and the minimum yield point of the brand.
