A straw chopper to be mounted at the rear discharge of a combine harvester includes a housing with a feed opening and a discharge opening with a rotor mounted in the housing for chopping and accelerating the crop materials. The rotor has a hub and a plurality of flail blade members where at least some of the blades are formed of a plate having a mounting hole through the plate for mounting on a bushing or pin of the rotor where a bearing surface of the mounting hole of the plate and not the plate surface is coated with material such as tungsten carbide or chromium carbide of a thickness less than 0.020 inches which is harder than a parent material of the plate.
