strength of materials?

Question

wahts the minimum yield strength for high tensile strenght bars

Answer 1

It depends on the material of the bar and on the heat treatment of the bar.

An SAE 1020 carbon steel bar, which is not considered a high tensile strength material, in the annealed condition has a minimum yield strength of 38,000 psi, but if it is heated, quenched and tempered, its yield can be increased to 62,000 psi.
A low alloy heat treated steel of iron, nickel, chromium and molybdenum, heat treated, has a minimum yield strength of 125,000 psi.

Answer 2

400 mpa

Answer 3

4000lb