Sandvik has launched Osprey MAR 55, a highly versatile tool steel powder that bridges the gap between maraging steels and tool steels. With this new alloy manufacturers no longer have to choose between good weldability of carbon-free maraging steels and the performance of carbon-bearing steels. Osprey MAR 55 provides good mechanical properties and wear resistance already in the ‘as-built condition’.
The new steel powder is primarily designed for excellent PBF-LB processability without the need for plate pre-heating. This makes it ideal for tooling applications that require hardness levels above 50 HRC and wear resistance exceeding that of the 18-Ni class of maraging steels.
The alloy could be considered for general tooling applications. The exceptional fracture toughness at ultrahigh strength levels paves the way for the use of the tool steel in defence and aerospace.
lngemar Bite, R&D manager at Seco, leading global provider of metal cutting solutions, said: “To me MAR 55 is the material with the most interest and attention today. It has now, after evaluations and extensive testing, been implemented in our production. We have used it both for prototyping and field testing, and products that are running today in our customers’ production.”
Exceptional toughnessFaraz Deirmina, principal metallurgist at Sanvik’s Powder Solutions, said: “Before MAR 55, customers had to choose between good weldability and performance. This new alloy bridges the gap between maraging steels and carbon bearing tool steels. It means that the alloy is easily weldable, with exceptional toughness. Also, it can be heat-treated without the need for prior costly solution annealing (austenitisation) or cryogenic treatments. At the same time its wear and fatigue resistance are similar to the carbide strengthened tempered martensitic microstructures of medium carbon tool steels.”
Osprey MAR 55 shows enhanced nitriding properties and its hot hardness (up to 600°C) is improved compared to 18Ni300 maraging steel. Compared to 18Ni300, the content of both nickel and molybdenum is reduced by 50%. The leaner composition in MAR 55 significantly reduces both energy and emission factors. Using the emission factors and nominal chemistries for both alloys there is a reduction of 21% in embedded CO
2 (emission factor tCo2/t) and a reduction of 26% in embedded energy (KWh/kg) for the raw material make-up in MAR 55 versus 18Ni300. This is based on nominal embedded energy factors for virgin materials. If recycled raw materials are used, then energy and emissions are further reduced.
Moreover, customers (Seco included) are confirming a longer service life using MAR 55 compared to 18Ni300. Higher longevity of the components before repair or replacement is needed to help customers achieve their sustainability goals.