Rapporten beskriver en utvärdering av nötnings- och korrosionsbeständiga material för en transportskruv för avfallsbränsle i en typisk miljö vid avfallseldade CFB-pannor. Utprovning har genomförts i både kontrollerad laboratoriemiljö och i verklig miljö vilket har gett en bättre förståelse för vilka konstruktionsmaterial som lämpar sig bäst i denna tuffa miljö och gett en modell för att i framtiden bättre kunna prediktera slitagehastigheten. De förändrade driftförhållanden, framförallt lägre varvtal, som den nya transportskruven har medfört (installerad i februari 2007 och med vilken fältproven har genomförts) har förskjutit nötning/korrosion förhållandet så att korrosionen är mer dominerande i nötningskorrosionen. Detta är tydligt då SS 2377 (rostfritt duplext stål), som är det mjukaste av de utvärderade materialen, uppvisar lågt slitage till följd av sitt goda korrosionsmotstånd. Konstruktionen av skruven har visat sig vara väldigt avgörande för nötningskorrosion

Rail lubrication in curves was widely introduced in Sweden during the 1970’s due to the high wear rate of gauge faces in sharp curves. The first tests performed in Sweden showed that lubrication decreased wear rates by roughly 10 times. Based upon these results, the Swedish track system was equipped with wayside lubricators called Clicomatic. Aside from wear, rolling contact fatigue (RCF) is another limiting factor in railway infrastructure productivity. Head checking is one of the fatigue forms that arises in curves of heavily loaded tracks as well as fast train tracks. Head checkings grow at the rail head, close to the gauge corner. High pressure and a sliding motion lead to plastic strain of the material from the rail ball towards the gauge face. There is a coupling between wear rates and RCF damages, high wear rates may lead to reduced RCF damages and vice versa. Hence, frequent application of lubricants to the rail does extend the rail life by several times but may, on the other hand, lead to fatigue problems. Preventive grinding in combination with lubrication has been the most efficient way to avoid fast degrading of curved rail track. This thesis concerns the progress of rail lubrication in terms of how environmentally adapted lubricants function both in wayside lubricators and at the track. Another aspect of the thesis is to find a lubricant able to reduce the wear rate at the gauge face while simultaneously decreasing the crack growth at the rail head. One thought was to use controlled wear to reduce rolling contact fatigue. Controlled wear in this situation means that the usage of a lubricant should give a sufficiently high wear rate to continuously wear off the surface layers. Another idea along the same lines was that of low contact friction. Low friction in the contact gives less plastic strain and subsequently less head checking. Rapeseed oil had shown low contact friction in earlier testing, therefore, synthetic esters were of interest to examine in this application. From both field tests and laboratory tests it was concluded that the wear protection for environmentally adapted lubricants was comparable to that of previously used lubricants if they were applied by trackside lubricators. Although they were known to be more sensitive to low temperatures, testing showed how to overcome this issue. Wear and friction tests were performed in the laboratory to evaluate lubricating blends. The tests evaluated rolling / sliding as well as pure sliding contacts. The research performed in this thesis yielded the following results. Pure synthetic ester (TMP-Oleat and TMP-C8-C10) in a sliding contact resulted in high wear rates and a lot of abrasive marks at the surface. By adding friction modifiers, the friction as well as the wear rate decreased considerably in the sliding contact. In the rolling sliding contact, synthetic ester alone and synthetic ester with the addition of friction modifiers both showed similarly low friction and wear rates. PAO gave higher friction, but at the same time, the surfaces had significantly fewer cracks as compared to synthetic ester formulations. One observation was that surfaces lubricated by synthetic esters became less hard and the hardness interval was wider than those lubricated with PAO. One explanation is that even if the overall friction is low, local spots of high friction between asperities can lead to localized strain and crack initiation. The conclusions are that Rapeseed oil is the recommended base for rail lubricants. The tested synthetic esters are a more expensive alternative useful if excellent low temperature properties are needed. Graphite is not necessary in the lubricant if it is applied continuously by a wayside lubricator. Twin-disc tests showed that low contact friction does not necessary mean that crack initiations are avoided in the surface. In conclusion, the base fluid and the additives influenced not only the wear rate but also the ability for cracks to grow.

Headchecks are a common type of damage in heavily loaded curved freight tracks. This paper deals with synthetic ester formulations' ability to prevent damage caused by headchecks through mild tribochemical wear. An experimental study pertaining to wear and friction of two rail steels lubricated by two synthetic ester base fluids, TMP-oleate and TMP-C8-C10, has been carried out. Six different free fatty acids were used in this study to act as performance additives. Three of the fatty acids were mono-acids with different, straight, carbon chain lengths (stearic acid C18, decanoic acid C10 and octanoic acid C8), one was a mono-unsaturated straight-chain fatty acid (oleic acid C18:1) while two were dibasic acids with intermediate carbon chain length (C9 and C10). Each fatty acid was blended with either ester, one at a time. The tests were carried out by using a high frequency reciprocating friction and wear test machine. In these tests, the gage face/wheel flange contact was simulated, and all tests were conducted in the boundary lubrication regime. An initial contact pressure of 316 MPa and a maximum sliding speed of 0.11 m/s were employed during the tests. The tests showed a wide range of wear rates, as well as different surface features depending on the interactions between synthetic esters, fatty acids and steel. The use of stearic and azaleic acid in lubricating rail steels results in very smooth surfaces with significant differences in their wear rates.

In this paper, the influence of concentration level and chemical composition of three different additive types on friction and wear coefficient are presented for a synthetic ester base fluid and a mineral base oil. One extreme-pressure (EP), two antiwear (AW) and two yellow metal passivator (Cu-passivators) additives were used. Factorial experimental design was used as the basis for a systematic evaluation of wear rates under mixed and boundary lubrication conditions. A total of 33 different lubricant blends were tested in a Plint and Partner High Frequency Friction Machine. For the synthetic ester, the extreme-pressure (EP) additive, containing phosphorus and nitrogen, was found to be much more effective in reducing wear than either of the two antiwear (AW) additives tested. In fact, the AW and Cu-passivator additives made little or no contribution to the wear protection in most of the cases studied. A synergy effect between the three additive combinations was observed only for the reference mineral oil blend. A significant difference between the antiwear performance of the test lubricants was found. This study suggests that the traditional "AW" and "EP" labels associated with commonly used additives are poor aids when designing of ester based lubricants.

Since the middle of the 1970s, lubrication of the high rail flange has been used to reduce wear rates. Field tests have been taking place since 1997 to evaluate the differences in wear characteristics between mineral oil based grease and new environmentally adapted greases. The field tests have also investigated whether the addition of graphite contributed to reduced flange wear. The wear reducing effect of trackside lubrication as a function of distance from point of application of the grease was also investigated. The field tests showed that environmentally adapted greases can be used without risk of increased rail wear and that the addition of solid lubricants, such as graphite, has no significant effect on the rate of wear. The highest wear rates were found during winter months when active lubrication stops due to problems associated with the sub-zero temperatures common in northern Sweden. Year-round lubrication would be expected to decrease wear rates significantly.

Rail and rail wheel flange wear on the rail track has been a problem of attention for the last 30 years. The problems arise in curves and depend on increased traffic volume, heavier axle load and also higher speed. Axle loads of 22,5-25 ton is common nowadays and the trend is towards heavier axle loads where the next step is 30-35 ton. Flange wear includes both wheel and rail flanges and is therefore a problem for the operating company as well as the infrastructure owner. The flange wear depend mainly on the number of passed axles, type of traffic, speed and curve radius but also the axle load contributes. Flange lubrication on high rail is a well known way to reduce wear since the middle of 70th and a number of techniques to lubricate the rail flange are developed as grease, aerosol of oil and dry stick with solid lubricants. The trackside lubricator can not apply the grease on the rail flange when the climate is during the winter. The infrastructure owner in Sweden was interested to evaluate the effectiveness of the track side lubricator. The investment in trackside lubricators over 20 years was about 75 Mkr (7,6 USD) and also an additional yearly costs to operate 3000 apparatuses. The work to evaluate effectiveness of the lubrication started 1997 there one of the important matter concern the possibility to use environmentally adapted lubricants without hazard the rail. This licentiate thesis concern effectiveness of trackside lubricators to reduce wear in sharp railroad curves. Also the environmentally aspects have been considered and therefore natural esters synthetic esters and additives suited for those kind of lubricants have been evaluated. The research proved that environmentally adapted lubricants could lubricate as good as earlier used greases. Some amount of metal removal is probably healthy for this kind of application. Lubricants as synthetic esters can be designed get those qualities. It was also found significant difference between the seasons concerning flange wear. This difference depends on the problem to apply grease on the rail flange during the winter.