High-speed steel vs Tool steel
High-speed steel displaced Tool steel, and 2 measured properties show why — density most clearly.
High-speed steel vs Tool steel
High-speed steel
Tool steel that stays hard when it is red hot — which is what let machine tools run fast enough to change manufacturing.
Tool steel
Steel that cuts, forms or shapes other materials — hard enough to hold an edge and tough enough not to shatter, which are opposing requirements.
| Property | High-speed steel | Tool steel |
|---|---|---|
| Density | 8–8.7 g/cm³ higher | 7.7–8.1 g/cm³ |
| Melting point Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 1370–1450 °C |
| Tensile strength Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 600–2500 MPa |
| Vickers hardness These are values for different forms — hardened and triple-tempered and hardened and tempered — so the numbers describe different substances rather than a difference between them. | 800–950 HV | 600–900 HV |