Key Performance Characteristics
- 71 – 74 HRC hardness
- Extreme resistance to abrasion while maintaining significant toughness
- Alternative to 65% tungsten carbide PAW materials
- Provides exceptional uniformity of hardness and wear performance across a range of service environment
SHS9290P represents a technical leap in the development of advanced PTA hardfacing powders since it contains no added tungsten carbide, no nickel and no separate matrix. SHS9290P is designed to replace and be superior to existing PAW powders, including industry standard nickel/chromium/boron/silicon types laden with up to 65% tungsten carbide, traditionally used for extreme abrasion resistance. When applied as a PTA weld overlay, homogenous deposits are produced with extreme resistance to abrasion while maintaining significant toughness. The as-welded deposits contain a high proportion of submicron and near-nano borocarbide phases formed during solidification providing exceptional uniformity of hardness and wear performance across a range of wear environments.
SHS9290P allows high undercooling to be achieved prior to nucleation and growth. This results in significant refinement of the microstructure over conventional alloys solidifying via conventional liquid solidification growth modes. SEM backscattered electron micrographs (right) illustrate the differences in the microstructural scale of PAW hardfacing deposits. SHS9290P exhibits complex borocarbide phase scales which are much finer than 65% angular tungsten carbide or 60% spherical tungsten carbide deposits. This reduced microstructural scale promotes a highly uniform wear rate throughout the volume of the SHS9290P deposit. The highly refined (submicron) structure of SHS9290P makes the weld overlay deposit much more resistant to fine particle abrasion and erosion since the scale of the microstructure is finer than typical wear erodents (i.e., debris and particles). In contrast, the large scale of angular or spherical tungsten carbide particles in competing materials can lead to preferential wear of the matrix and cracking/pull-out of the hard tungsten carbide particulates.
EXTREME ABRASION/EROSION RESISTANCE
SHS9290P is designed to exhibit extreme abrasion/erosion resistance resulting from its unique structure consisting of high volume fractions (i.e. 60% – 70%) of highly refined complex borocarbide phases that result in extreme hardness of 71 – 74 HRC in hardfacing deposits. In the table to the right, ASTM G65-04 Procedure A wear testing shows a large number of wear results on 60 – 65% tungsten carbide PTA weld overlay samples as compared to SHS9290P weld overlay samples. Wear resistance can vary widely for tungsten carbide PAW materials due to tungsten carbide breakdown and dissolution during welding, and non-uniform distribution of tungsten carbide particles in the deposit as a result of size and density differences during welding. However, typical SHS9290P wear rates are low and exhibit little difference between the first and second 6,000 cycle tests based on the uniform and refined scale of the microstructure.
Uniform Wear Performance
The SEM secondary electron images of 65% angular tungsten carbide PTA, 60% spherical tungsten carbide PTA and SHS9290P weld deposits were taken in the wear scar after 12,000 total cycles of ASTM G65-04 testing. When comparing the SHS9290P deposit surface to the surface of angular and spherical tungsten carbide deposits, the wear is uniform across the SHS9290P deposit while the matrix in the two tungsten carbide deposits is being preferentially worn out due to the non-homogenous nature of these deposits.