Fatih Hayati Çakır

Maintenance Error Detection Procedure and A Case Study of Failure Analysis Locomotive Diesel Engine Bearings

This paper presents a maintenance error detection algorithm. Proposed algorithm is used to determine failure analysis of a locomotive diesel–electric engine. Although the inspected engines had been performing normally up to the maintenance sequence, the problem occurred after the maintenance and resulted in a complete stop of the engines with the high losses on-site. In failure cases, before focusing on technical problem narrowing down possibilities were required. After initial analysis, many possibilities were eliminated and the problem was determined with less effort on shorter time. Engine bearings were investigated to diagnose the problem. The origin of the problem was diagnosed and determined using SEM techniques and on-site inspections. The results show that the shot peening technique used in engine block cleaning operations caused the deterioration of the engine. Oil filters were damaged and could not hold shot peen particles. The oil filter and engine bearing have been examined with SEM and EDS analyses to determine the source of the particles. Some of the found ferrous particles had a spherical shape of 300–1000xa0µm. These particles and the high pressure created by the engine’s oil pump used to cool the system caused severe abrasive wear.

Effect of Isothermal Bainitic Quenching on Rail Steel Impact Strength and Wear Resistance

The effect of heat treatment regimes on hardness, impact strength, and wear resistance of rail steel for high-speed tracks (rail quality category R350HT) is studied. Analysis of steel properties with a different structure is compared: pearlitic, and upper and lower bainite. It is shown that the steel with bainitic structure has the best impact strength, but wear resistance is better for steel with a lower bainite structure.