ISO 4263-4:2006

Petroleum and related products — Determination of the ageing behaviour of inhibited oils and fluids — TOST test — Part 4: Procedure for industrial gear oils

ISO 4263:2006 specifies a method for the determination of the ageing behaviour of gear oils of categories CKC, CKD, CKS and CKT as defined in ISO 6743-6. The ageing is accelerated by the presence of air and elevated temperatures, and the degradation of the oil is assessed by the change in kinematic viscosity at 100 °C, the insoluble content (precipitation number), and possibly the acid number increase, the sediment content by filtration, the additives content variation and the infra-red oxidation.