What is 45# round steel mainly used for?

45# round steel refers to the cross-section of the round solid long steel. Its specifications to the diameter of du millimeters, such as "50" that is, the diameter of 50 mm round steel.
45 # round steel is divided into hot-rolled, forged, and cold-drawn three kinds. Hot rolled round steel specifications for 5.5-250 mm. Among them: 5.5-25 mm of small round steel is mostly supplied in bundles of straight bars, commonly used for rebar, bolts, and a variety of mechanical parts; greater than 25 mm round steel, mainly used in the manufacture of mechanical parts or for seamless steel pipe billet.
Chemical composition:
Carbon C: 0.42 ~ 0.50 silicon Si: 0.17 ~ 0.37 manganese Mn: 0.50 ~ 0.80 sulfur S: ≤ 0.035
Phosphorus P: ≤ 0.035 chromium Cr: ≤ 0.25 nickel Ni: ≤ 0.25 copper Cu: ≤ 0.25
Mechanical properties:
Tensile strength σb (MPa): ≥ 600 (61) Yield strength σs (MPa): ≥ 355 (36)
Elongation δ5 (%): ≥16 Section shrinkage ψ (%): ≥40
Impact work Akv (J): ≥39 Impact toughness value αkv (J/cm2): ≥49(5)
Hardness: unheated, ≤229HB; annealed steel, ≤197HB
Specimen size: specimen size 25mm