Abstract: In order to create a wear-resistant surface armoring suited for autogenous wear protection for the rolls of high-pressure roll presses for pressure disintegration of granular material using nap bolts (grid armoring), which also comprises a high serviceable life span even under the effect of high-pressure loads, it is proposed to give the nap bolt the shape of a mushroom, whose head projects outward from the roll body and whose shaft is sunk into the corresponding recess or bore of the roll body in such a way that an open space remains between the base of the bore and the lower end of the shaft of the bolt.