Hardness conversion
45 HRC is roughly 446 HV, 421 HB, and about 1500 MPa (217 ksi) tensile strength for non-austenitic steel, per ASTM E140. This page converts between Rockwell C (HRC), Vickers (HV), Brinell (HB, 3000 kg), and approximate tensile strength — type a value and scale, and it prints the seven-row window around your value.
Cross-scale hardness conversions are approximate by definition: the scales measure different indentation responses, so treat converted values as indicative (±1–2 HRC is typical), not certified. The tensile columns are estimates and are omitted above roughly 48 HRC where the correlation breaks down.
How accurate are hardness conversions?
Rockwell, Vickers, and Brinell each load a different indenter in a different way, so there is no exact algebraic relationship between them — the conversions come from empirical correlation tables (ASTM E140) built for a defined material class, here non-austenitic steels.
Expect agreement to about ±1–2 HRC. Brinell becomes unreliable above ~60 HRC (the indenter itself starts to deform) and tensile-strength estimates lose validity above ~48 HRC; both are shown as — in those rows rather than guessed.