| AISI S1 | |
 | |
| Category | Steel |
| Class | Tool steel |
| Type | Shock-resisting steel |
| Designations |
France: AFNOR 55 WC 20 Germany: DIN 1.2550 Italy: UNI 58 WCr 9 KU United States: ASTM A681 , FED QQ-T-570 , SAE J438 , UNS T41901 |
| Composition | |
| |
| Element | Weight % |
| C | 0.40-0.55 |
| Mn | 0.10-0.40 |
| Si | 0.15-1.20 |
| Cr | 1.00-1.80 |
| Ni | 0.30 |
| Mo | 0.50 |
| W | 1.50-3.00 |
| V | 0.15-0.30 |
| Cu | 0.25 |
| P | 0.03 |
| S | 0.03 |
| Mechanical Properties | |
| |
| Properties | Conditions | ||
| T (°C) | Treatment | ||
| Density (×1000 kg/m3) | 7.88 | 25 | |
| Poisson's Ratio | 0.27-0.30 | 25 | |
| Elastic Modulus (GPa) | 190-210 | 25 | |
| Tensile Strength (Mpa) | 690 | 25 | annealed more |
| Yield Strength (Mpa) | 415 | ||
| Elongation (%) | 24 | ||
| Reduction in Area (%) | 52 | ||
| Hardness (HRB) | 96 | 25 | annealed more |
| Impact Strength (J) (Charpy unnotched) |
249 | 25 | oil quenched from 930°C, single tempered at 205°C more |
| Thermal Properties | |
| |
