The M789 – Precipitation Hardenable Stainless Steel – BÖHLER material, combines the easy printability of a Maranging Steel with the
corrosion resistance of a 17-4PH (Stainless Steel AISI630).
The M789 reaches high tensile strength (up to 1800 MPa) and hardness values (up to 52HRC) after heat treatment, which makes usable for structural components that usually where made using high performance structural steels, such as AISI 4340 and Maraging M300.
Furthermore, the M789 steel is a corrosion resistance steel rather than other high performance structural steels, hence it is possible to avoid to use galvanic coatings (e.g. cadmium and chromium, VI and III).
These properties allow to use the M789 steel for shafts, brackets, dies, gears and impellers operating in mild to heavy corrosive environments.
| Mechanical Properties | Test Method | As Built | Heat Treated |
| Yield Modulus | EN ISO 6892-1 | 175-185 GPa | 185-195 GPa |
| Yield Strength (Rp 0.2%) | EN ISO 6892-1 | 700-800 MPa | 1390-1710 MPa |
| Tensile strength | EN ISO 6892-1 | 1000-1040 MPa | 1570-1800 MPa |
| Elongation at Break | EN ISO 6892-1 | 7-14 % | 2-6 % |
| Charpy V-notch test | EN ISO 148-1 | - | 6-14 J |
| Hardness | EN ISO 6508-1 | 20-30 HRC | 52-58 HRC |
| Chemical Composition and Physical Properties | ||
| Chemical composition |
C Cr Ni Mo Al Ti |
< 0,02 % 12,2 % 10 % 1 % 0,6 % 1 % |
| Physical Properties | Density | 7,85 g/cm3 |