BS ISO 6280:2018 pdf download – Plain bearings — Requirements and guidance on backings for thick-walled multilayer bearings

BS ISO 6280:2018 pdf download – Plain bearings — Requirements and guidance on backings for thick-walled multilayer bearings This document gives requirements and guidance to obtain the optimum bond between backing and bearing metal for thick-walled multilayer plain bearings. This optimum bond depends on the chemical composition, the state of stress, the structural arrangement and the machining of the bond surface of the backings. NOTE Control of the manufacturing process is an important requirement to achieve an optimum bond between backing material and bearing metal. 2 Normative references There are no normative references in this document. 3 Terms and definitions No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso.org/obp — IEC Electropedia: available at http://www.electropedia.org/ 4 Backing materials 4.1 General Steel and cast steel, cast iron with lamellar and spheroidal graphite as well as cast copper alloys are used as backing materials. For cast iron backing, additional dovetailed grooves may be used on bond surface for mechanical anchoring. 4.2 Steel and cast steel Before lining, the backing is heat-treated for normalizing and stresses relieving. Typical contents of elements for bonding: — C < 0,25 % (mass fraction); — Cr ≤ 1,1 % (mass fraction); — Ni < 0,5 % (mass fraction); — Mn ≤ 1,3 % (mass fraction). The hydrogen contents of a backing having a thickness of 40 mm or more shall be not more than 1,7 ppm. A properly-controlled process shall be used to reduce the hydrogen content to a level that ensures trouble-free running of the bearing during its initial period operation. 4.3 Cast iron The microstructure should be ferritic or largely ferritic. Typical contents of elements for bonding: — Si < 2,5 % (mass fraction); — P < 1,2 % (mass fraction); — C < 3,35 % (mass fraction). 4.4 Cast copper alloys EXAMPLES CuSn10, CuPb5Sn5Zn5. 5 Machining of bond surface The bond surface on the backing should have a surface roughness of R a = 8 µm maximum. Final machining should be carried out without material cutting fluids unless degreasing methods are subsequently used prior to metallization. BS ISO 6280 pdf download.