Wear resistance is closely associated with the hardness of the base metal. Our friend Greg gave you some good information. An abrasion resistant material will improve the service life of your fan blades, but they can be more difficult to weld and they are more expensive than mild steel. One other option to consider is to apply a hard abrasion resistant coating to those areas where the abrasion is most severe. Thermally applied coatings can be very cost effective because they allow you to use inexpensive, easily welded base metals and provide a wear surface with the characteristics that are most effective for your service conditions.
One of my clients uses this approach on their product that is subject to extremely abrasive operating conditions. They extended the service life from six months to about two years between grinding operations to true up the wear surfaces.
Best regards - Al