Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1399684
46 | July - August 2021 | www . machinerylubrication.com OIL ANALYSIS was found, it is a best practice to follow the manufacturer's recommendation. While using an unapproved 150 cSt oil, it can be observed that ferrous wear increased while having a low count on contam- inants. is can be shown in both elemental analysis wear trend (Figure 7), contaminants trend (Figure 8) and particle quantifier index. An increase in the iron count can be considered normal. It is the nature of a gearbox to transmit torque by the inter- ac t ion bet ween reduc t ion components and variable loads can increase the possibility of having metal-to-metal contact, resulting in wear. However, in this case, the ferrous wear exceeded the wear limit set by end-user in one year, which can be considered as an abnormal increase of wear and resulted in scheduling oil change. A s b ot h i r on c ou nt and particle quantif ier had increased, it is likely that reduc- tion components are being worn out. Once the viscosity was increased to 220 cSt, the rate at which ferrous wear was generated was reduced by more than half, or in other words, the ferrous wear limit did not exceed the limit of 100 ppm in two years. If both wear and contam- inant trends are analyzed, it can be concluded that once the viscosity changed, the wear was generated as a result of contam- ination and less likely to be due to poor lubrication. Both water content and oxidation affect the performance of the lubricant. Once these two characteristics are analyzed, it makes sense that ferrous wear was increased while using the unapproved 150 cSt oil. Figure 5: Used oil analysis results for chain conveyor gearbox. Sampled 08 Feb 2011 17 Sep 2012 21 Sep 2015 28 Sep 2016 21 Aug 2017 Reported 12 Feb 2011 20 Sep 2012 06 Oct 2015 07 Oct 2016 30 Aug 2017 Lubricant Contamination Rating Normal Normal Normal Normal Normal Equipment Rating Normal Normal Normal Normal Normal Oil Rating ALERT ALERT Normal Normal Normal Diluted ISO Code (4/6/14) 24/24/20 Particle Count (Diluted) >4um 159411 Particle Count (Diluted) >6um 117932 Particle Count (Diluted) >14um 6415 ISO Code (4/6/14) 21/19/16 22/20/15 22/21/19 22/21/18 Particle Count >4um 13296 22003 25845 28641 Particle Count >6um 3807 6649 18136 18317 Particle Count >14um 537 276 3164 1487 PQ Index 0 40 11 22 77 Visc @40C (cSt) 136.7 158.6 205.8 210.6 219.3 Oxidation (Ab/cm) 2 4 1 0 TAN (mg KOH/g) 0.83 Water (Vol%) 0.013 0.018 0.007 <0.003 <0.003 ICP Wear Debris (ppm) AI (Aluminum) 0 0 0 0 0 Cr (Chromium) 0 1 0 0 0 Cu (Copper) 6 0 0 0 0 Fe (Iron) 35 135 45 57 96 Mo (Molybdenum) 0 0 0 0 0 Ni (Nickel) 0 0 0 0 0 Pb (Lead) 0 0 0 0 0 Sn (Tin) 0 0 2 0 1 ICP Contaminants (ppm) K (Potassium) 0 1 0 0 0 Na (Sodium) 3 6 1 0 0 Si (Silicon) 1 4 8 6 17 ICP Additives (ppm) B (Boron) 2 3 2 3 1 Ba (Barium) 6 17 0 0 0 Ca (Calcium) 39 23 0 0 1 Mg (Magnesium) 2 0 0 0 0 P (Phosphorus) 362 229 316 317 403 Zn (Zinc) 344 8 2 1 1