OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 6 1 4 a b Fig. 4. Annular gear cross section (a) and a fragment of the “Area” of this cross section (b) a b Fig. 5. X-ray diff raction patterns of the objects in fi gure 4, b: a – Spot 1; b – Area 2 of Area 2 (see fi gure 4, b). The selected surface area is about 2,600 μm2. An X-ray pattern of the surface is shown in fi gure 5, b. The main chemical element of the analyzed objects is carbon, making almost 57 % (Table). This is followed by chlorine (17 %), sulfur (12 %), oxygen (8 %), zinc (5 %) and magnesium (about 1.6 %). The chemical composition of this material is more consistent with chloroprene rubber. Nitrile butadiene rubber is also close to this chemical composition. There are no fundamental diff erences between the compositions of the diamond bearing layer and the geared rim material. The composition of the diamond bearing layer contains an average of 1.5–2.0 % more sulfur, which is consistent with its higher hardness compared to the hardness of the annular gear material. It can be assumed that the basis of the diamond bearing layer and the annular gear are two materials similar in chemical composition, for example, chloroprene and butadiene-nitrile rubbers, with the addition of various fi llers (binders, softeners, stabilizers, accelerators, vulcanizers, etc.). This rubber with fi llers acts as a bond for the diamond bearing layer and the annular gear material. In the fi rst case, the bond binds and holds diamond or abrasive grains (powders), in the second it binds aluminum powder (GOST 60582022). The aluminum powder in the composition of the annular gear material performs a control function and determines the service life of the diamond hone. The appearance of light spots of aluminum powder inclusions on the dark functional surface of the hone teeth indicates the wear of the diamond bearing layer and the need to replace the abrasive tool. Based on studies of hardness and tensile strength, the optimal range of components of the abrasive layer and annular gear material was determined. Shore hardness of the specimens with an abrasive is 93–95 units, with aluminum powder it is 85–88 units, ultimate strength is 14 MPa and 11 MPa, respectively.
RkJQdWJsaXNoZXIy MTk0ODM1