record disc used for agricultural use, including the establishment of a labour

摘要

this disc is a metal disc having a central portion (10), especially for fixing the soft disk or the like, a chassis, and an outer peripheral part (12) which is intended, inter alia, tillage and having a hardness greater than that of the c central (10).the disk also has a transition zone (14) between the central part and the peripheral part (10) and (12), which has a hardness gradient in a radial direction and at least in the central part (10), a hardness gradient in the thickness of the disc.