Paraffinic Mineral Oil Research Articles

Effects of Lubricant Oil Film Thickness on Seizure Initiation in Cold Extrusion of Aluminium

A critical condition for seizure initiation has been investigated under a relatively low extrusion speed using an extrusion-type friction testing machine. To examine the effects of lubricant oil film thickness on seizure initiation, the oil film thicknesses at the tool-workpiece interface were estimated theoretically, and paraffinic mineral oils with three grades of viscosity were tested with various thicknesses of oil film applied, using commercially pure aluminium as the workpiece. The seizure phenomenon was always near the die exit. The lower the viscosity grade of oil used and the thinner the oil film applied, the shorter the critical punch stroke for seizure initiation became. Consequently, it has been clarified that the critical oil film thickness for seizure initiation was about 0.2 μm.

Morphological changes in SBS block copolymers caused by oil extension as determined by absolute small angle x-ray scattering

A series of SBS block copolymers diluted with different amounts (0–60 wt%) of three different kinds of oil were investigated: 1) lithene PM (a low molecular weight polybutadiene); 2) a paraffinic mineral oil with its electron density close to that of the polybutadiene (PB) phase; 3) a highly aromatic mineral oil with an electron density close to the polystyrene (PS) phase. All the oils seem to go into the polybutadiene matrix. Paraffinic oil and lithene form a homogeneous phase with PB; the aromatic oil at low concentrations mixes with the PB phase with a high level of inhomogeneity, while at higher concentration partial phase separation occurs. In the undiluted polymer, styrene forms cylinders in hexagonal packing. The distance between cylinders (about 43 nm) is not significantly changed upon dilution up to 33 wt%. Previously proposed changes in the morphology of PS domains at larger oil contents can be related to observed changes in the long period, in the segment length distributions, and in the homogeneities of the phase (density fluctuations). The electron density difference obtained for pure SBS is lower than the theoretical one calculated from the densities of pure PS and pure PB. Dilution by paraffinic oil improves the phase separation.

Acute Inhalation Toxicity in Rats Exposed to Thermal Degradation Products of a New Chlorinated Fluid for Electrical Transformers

The dielectric fluid LIHT-TI, a 60:40 mixture of tetrachlorobenzyl toluene and trichlorobenzene, is used in electrical transformers. The acute in halation toxicity of its thermal decomposition products was assessed in rats. Askarel-T1, a 60:40 mixture of 6 chlorobiphenyl and trichlorobenzene, and a paraffinic mineral oil were also tested for comparison purposes. Animals (6 per group) were exposed for one hour to atmospheres resulting from heating the fluids to 500 °C and 700 °C. They were followed for 14 days after exposure. No mortality occurred in the LIHT-T1 group. Only slight and transient respiratory discomfort was noticed during exposure. The effects on growth were virtually nil, expected for some slight initial retardation during the first two days post-exposure. The effects induced by Askarel-T1 were similar if a little more pronounced. Initial retardation of growth lasted longer, respiratory im pairment was more important, and small lesions consisting of hemorrhagic areas were observed. The difference would not seem to be attributable to a greater degree of thermal degradation, since both Askarel-T1 and LIHT-T1 were only moderately decomposed.

A seizure initiation mechanism in cold metalworking processes. (5th Report, Effect of temperature).

An extrusion-type friction test has been carried out to examine the critical conditions for seizure initiation at various temperatures using a commercially pure aluminium as a work metal and paraffinic mineral oils as a lubricant. As the test temperature increased or the lower the lubricant viscosity decreased, the critical punch stroke for seizure initiation decreased. The oil film thickness trapped in the micro-pools on the tool-work interface was reduced with an increase in the temperature or a decrease in the viscosity grade of lubricant. As a result, it has been clarified that the critical oil film thicknesses for seizure initiation were approximately constant ; 0.20.25μm.

Energy conservation in stainless steel cold rolling applications

AbstractIn order to predict the performance of rolling oils in actual production mills, from tests in laboratory mills, the influence of various factors, such as shape factors work roll diameter (D), strip thickness (h1), operating conditions (reduction rate (r), peripheral velocity of roll (U0), strip velocity (U1)) and kinematic viscosity of the rolling oil (υ0) was investigated. A parameter RLI (Rolling Lubrication Index = u0(U0+U1)(1−r)(D/2h1.r)½) was found to be useful in predicting lubricating conditions in actual production mill applications.The coefficients of friction of mineral oils, some synthetic hydrocarbons including polybutene, and several kinds of additives were obtained from laboratory mills under the same condition of RLI value as that for finish rolling in actual production mills. With hydrocarbons, paraffins showed the lowest coefficient offriction, while aromatics exhibited a higher coefficient of friction, with naphthenes showing the highest.A high‐quality rolling oil was formulated using a combination of ester and paraffinic mineral oil. It is observed that this new oil can save 14% of energy consumed by a laboratory mill compared with conventional rolling oils. In production mills, nearly the same energy conservation level can be achieved.

Experimental study of grinding fluids for abrasive-belt grinding of stainless steel

A number of ferritic stainless steels with high corrosion resistance have recently been developed, but these steels are known to be difficult to grind in coated abrasive-belt grinding operations. In order to formulate or select an optimum oil-based grinding fluid with which such stainless steels can be successfully ground, an optimum base oil was first experimentally selected, and then additives were evaluated for their effect in improving abrasive-belt grinding performance. A paraffinic mineral oil having a certain viscosity was found to be suitable for the base oil. Chemical grinding oil additives were found markedly effective in improving the abrasive-belt grinding performance for both 19Cr-2Mo ferritic stainless steel and SUS 304 austenitic steel, with those containing sulphur or chlorine being superior to those containing phosphorus, fatty acid or alcohol. Among all the additives tested, chemically active oils, such as sulphurized mineral oil, exhibited the best performance. Effects of chlorinated paraffins on the grinding performance could be perceived but were not so great as those of sulphur-series additives. The addition of TCP (tricresyl phosphate) to the grinding oil containing sulphur reduced metal removal in the case of 18Cr-2Mo ferritic stainless steel (SUS 444). In the case of SUS 430 ferritic stainless steel, however, TCP increased metal removal for a comparatively low sulphur concentration, but, above an optimum concentration of 0.4 wt% S, metal removal was reduced by TCP addition. A comparison of sulphur-series additives added to a sulphurized paraffinic mineral oil showed that nonyl polysulphide was superior to any other additives for improving the grinding performance in 19Cr-2Mo steel (SUS 444) and SUS 430. Excess addition of sulphurized fatty oil to a grinding fluid lowered the cutting ability of abrasive grains.

Seizure initiation mechanism in cold metalworking processes. (3rd report Effect of oil film thickness on seizure initiation)

A critical condition for seizure initiation was examined using an extrusion-type friction testing machine. Paraffinic mineral oils with three grades of viscosity were tested with various oil film thicknesses, using a commercially pure aluminium as the workmetal. The seizure was always initiated near the die exit. The lower the viscosity of oil used and the thinner the applied oil film was, the earlier the critical punch stroke for seizure initiation was. The oil film thickness estimated theoretically in the previous report could not reasonably determine a critical value for the seizure initiation. Furthermore, the oil film thickness at the die exit was recalculated theoretically under the boundary condition of the trapped oil film thickness measured experimentally. As a result, it has been clarified that the critical oil film thickness for the seizure initiation was less than about 0.2μm.

Calorimetric measurements of paraffinic transformer oil containing pour point depressant.

In order to investigate how the addition of a pour point depressant affects the crystallization/melting characteristics of paraffin wax contained in a paraffinic transformer oil in a low temperature range, specimens were made by dissolving an oligomer consisting of ethylene-propylene copolymer into a paraffinic transformer oil. Heats of crystallization were calculated by measuring thermograms of the specimens between room temperature and -100°C, using Differential Scanning Calorimetry (DSC). Such physical properties as pour point, kinematic viscosity, etc., were also measured. Consequently, it has become clear that, when being subjected to cooling with the addition of a pour point depressant, the crystallization/deposition of its paraffin wax is disturbed within a temperature range of DSC crystallization peak temperature to -60°C, but its paraffin wax ends in crystallization/deposition regardless of its addition at about -80°C. In other words, its heat of crystallization within a temperature range of room temperature to about -80°C is constant, being independent of the addition of a pour point depressant. Finally, it is suggested that the approved theory that a pour point depressant does not disturb the deposition of paraffin wax crystals in a paraffinic mineral oil at low temperatures should be modified, based upon experimental results obtained by the author.

Storage stability of sulphurized sperm oil replacements I: Origin and nature of the sludge

Sulphurized sperm oil has been used in numerous lubricant formulations to improve their extreme pressure and antiwear properties. In the beginning of the 1970s, sperm oil became an almost unavailable and expensive raw material. Replacements have been developed, but they are also expensive. Many lubricant manufacturers seem to have turned to sulphurized glycerides, when possible since natural fats and oils are cheaper and more readily available than the synthetic replacements. The greatest limitation on the wider use of sulphurized glycerides in lubricating fluids is their low storage stability in compositions based on paraffinic mineral oils. This has not yet been an object of systematic investigation. The purpose of the experiments presented in the present paper was to examine and suggest the origin and nature of the sludge formed by sulphurized esters of fatty acids in paraffinic mineral oils. The storage stability of sulphurized soya bean oil, lard oil and a mixture of n-butyl and diethylene glycol esters of long-chain fatty acids in three paraffinic base oils was studied. Samples of sludge obtained from the additives after 12 months of storage were characterized. The experimental results confirm earlier observations with model additives that there are less than two sulphur atoms per double bond both in the bulk additive and in the sludge that it forms. The sludge samples were found to have substantially higher acidity than the bulk additives.

Subject index

Models for the temperature and pressure dependence of density, temperature and pressure dependence of the low-shear viscosity, and shear dependence of viscosity are directly applicable to elastohydrodynamic simulations. The models provide a means to relate the tribological behavior of the lubricated contact to the properties of the liquid lubricant. The success of the Newtonian assumption for the film thickness of squalane can be typical for neat, low-molecular-weight liquids that are used as lubricants such as naphthenic mineral oils, polybutenes, and low-viscosity paraffinic mineral oils. The assumption is reasonable for squalane to a shear stress of at least 5 MPa, which is not exceeded in the inlet zone. It is possible to produce an accurate prediction of the central elastohydrodynamic film thickness without solving simultaneously the Reynolds equation and the elastic film-shape equation.

On the Assessment of Lubricity in the Deformation Process by a Strip-ironing Type Friction Testing Machine : Fundamental Considerations and Measurements of Anti-weldability

A strip-ironing type friction testing machine, which can measure simultaneously normal and frictional forces acting on the die during the process, has been made on an experimental basis to assess an ability of lubricants to resist the welding at the tool-work interface in deformation processes. It can estimate effects of the bulk plastic deformation of metal ; i.e., an increasing ratio of the frictional surface area η and a sliding distance h on the welding which are important factors for the welding phenomena of the deformation process. To measure anti-weldability by this testing machine, paraffinic mineral oils have been tested with a commercially pure aluminum strip. The following conclusions were made. (1) The frictional coefficient μ and the average frictional shear stress can be expressed by the ratio of the welding area to the total contact area. (2) The ability to resist the welding of lubricants can be assessed by the contour lines of μ = constant on the η-h diagram.

General Properties of Mixtures of Paraffinic Insulating Oil with Alkylbenzenes

Mixtures of a paraffinic-base electrical insulating oil for oil-filled transformer use with a branchedchain type alkylbenzene with high viscosity, a branchedchain type dodecylbenzene and a straight-chain type dodecylbenzene were evaluated for improving the characteristics of a paraffinic mineral oil for transformer use. It has been demonstrated that blending the alkylbenzenes in the paraffinic oil brings about some improvements in its chemical, physical, and electrical properties. Moreover, it has been concluded that a modified paraffinic oil which contains 50% of the branched dodecylbenzene gives overall characteristics almost equivalent to the naphthenic transformer oil which is practically employed.

Electrical Properties of Some Naphthenic and Paraffinic Mineral Oils

The objective of this program was to compare the electrical performance of oils derived from the two recognized classes of crude stock -- naphthenic and paraffinic. Electric strength, both 60 Hz and impulse, partial discharge data and arc response (50amp arc interruption) of five oils from these above two categories indicate the interchangeability of these oils.

Effect of oil mists on the irritancy of sulfur dioxide. I. Mineral oils and light lubricating oil

The increase in pulmonary flow resistance in unanesthetized guinea pigs was used to assess the effect of sub-micrometer oil aerosols on the response to sulfur dioxide. At a concentration of about 10 mg/m3 neither a medicinal grade mineral oil nor a light lubricating oil altered the response when given simultaneously with 1 or 10 ppm sulfur dioxide. The naphthenic medicinal oil at 100 mg/m3 failed to protect against 50 ppm sulfur dioxide when administerd simultaneously. A 30-minute pre-exposure, however, conferred complete protection. A paraffinic laboratory grade mineral oil conferred protection when given simultaneously but was less effective when the pre-exposure protocol was used.

Some Chemical Effects in Boundary Lubrication Part I: Base Oil-Metal Interaction

Base fluid-metal interactions of a super-refined paraffinic mineral oil were studied. Wear debris from a Shell Four-ball wear tester was analyzed. Based on the amount of iron distributed among used oil, organic solid, iron particles, and iron oxides, one is able to interpret the wear phenomenon in terms of mechanical and chemical processes. Oxygen concentration at the wear junction controls the type of the chemical interactions between the metal and the lubricant. These chemical reactions appear to be controlled by the thermal gradient at the junction; catalytic effects by the metal are insignificant.

Estimation of the Molecular Junction Temperatures in Four-Ball Contacts by Chemical Reaction Rate Studies

A super-refined paraffinic mineral oil has been used to study the chemical reactions under boundary conditions in a four-ball wear tester. By quantatively analyzing the wear debris generated, chemical reaction rate data used to correlate between dynamic wear tests and static, externally controlled temperature runs. The reaction temperature at the wear junction has been estimated to be 351°C for 40kg load, 600 rpm, 75°C bulk oil temperature. This temperature is higher than the Blok-Archard flash temperatures calculated under the same conditions.

The sliding of copper-based sintered material against steel in paraffinic mineral oil

Coefficient of friction as a function of load and speed is obtained for the sliding of copper-based sintered material against steel in paraffinic mineral oil. It is shown that the coefficient is primarily temperature-dependent. In other words, the same coefficient is obtained for various load-speed combinations. Moreover, the values of the coefficient under transient temperature, with several rates of change, are nearly comparable with those for steady-state temperatures. The temperature range 230°–315°F is a good one inasmuch as the coefficient of friction is constant. The range above 315°F is undesirable as fading occurs (i.e., the coefficient of friction decreases with increases in temperature) which is conducive to stick—slip.

The sliding of copper-based sintered material against steel in paraffin mineral oil: Wear, Vol 11, No 5 (May 1968) pp 341–353

The sliding of copper-based sintered material against steel in paraffin mineral oil: Wear, Vol 11, No 5 (May 1968) pp 341–353

Influence of Oils on the Toxicity of Amitrole to Quackgrass

In field trials, 2 gpa of oil enhanced the herbicidal activity of 3-amino-1,2,4-triazole (amitrole) and a mixture of amitrole + ammonium thiocyanate (hereinafter referred to as amitrole-T) on quackgrass (Agropyron repens(L.) Beauv.). None of the oils consistently increased the toxicity of other foliarly-applied herbicides. A paraffinic mineral oil enhanced the activity of amitrole on quackgrass to a greater degree than NH4SCN. The inclusion of a paraffinic mineral oil enhanced both the amount and the rate of14C-amitrole and amitrole-T translocated from the treated leaf to the shoots and roots, this being more pronounced with amitrole (twelvefold) than with amitrole-T (twofold).

The sliding of copper-based sintered material against steel in paraffinic mineral oil

Copper-based sintered material was slid against steel in paraffinic mineral oil, with the careful measurement of surface temperature, ambient oil temperature, normal load, and friction force. The coefficient of friction under constant load and constant velocity followed distinct, reproducible levels of constant value, as a function of temperature. The levels occurred in a definite sequence omitting no intermediary levels. The consequence was an apparant decline in the coefficient of friction with increasing temperature, independent of viscosity changes occurring in the oil. The surface temperatures at which transitions among the friction levels occurred, were dependent on the time-temperature history of the oils. The causation does not appear to be mechanical, to be the result of changes in the materials, or to be a consequence of the lubricant alone. It is most likely a chemical phenomenon of the system as a whole