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Impact on mechanical wear of physical property of the grease

14th December 2013 Bearing Technology 1 Comment

Abrade while being what is called, refer to the intersection of antithesis and surface of movement pair the intersection of work and external material lose or produce course of residual deformation constantly at the relative motion. It is mainly the mechanical function because among the surfaces of antithesis to abrade the course, return sometimes in addition, the chemical action is produced. Usually this mechanical function refers to tribological function, and the chemical action often refers to the erosion effect of environmental mediums and chemistries. When grease lubricate, lubricate adipose membrane, can reduce the intersection of antithesis and external abrasion and prevent the intersection of erosiveness and material from enter.

It is three major causes causing machine component to be damaged and failed to abrade, wear out and rupture. Break-in run and shut while only abrading during the course of abrading and beginning to take place or slightly May sleek surface a bit. So, much machinery, for example the car needs to carry on break-in before putting normal operation into. Generally speaking, after the part is abraded, often cause mechanical precision lose and loss of efficiency, therefore need to change or maintain, force the mechanical production rate to reduce. In machinery works, the economic loss that leads to the fact because of abrading every year is very surprising. Someone estimates, more than 1/ 3 of the world energy are shown as the friction loss in various forms finally while various machinery transmit energy. Because the decreasing densely of surface of antithesis, cause the apparatus to be damaged, need changing the attrited part, so the total output value of the accessories and steel products amount consumed, often nearly produce the required one with the host computer equally. Adopt various lubricant including grease, can reduce the friction loss greatly, reduce abrasion and extension mechanical life time of the accessories, thus all right power saving and reducing the consuming in a large amount of steel products.

First, appearance

The appearance examines a simplest method of grease quality through the ocular feeling. For instance color, diaphaneity and homogeneity,etc. can be estimated out; The flavor can be smelt with the nose such as taking a sniff at; If the size, soft hard intensity, impurity particle size of the grease wire drawing fiber can fumble out by hand. So, through physiognomic test, can judge the quality of the grease and kind of differentiation grease tentatively. For example the sodium based grease is the fibrous structure, can draw into the longer silk, strong to the adhesion of the metal surface.

Second, drop point

Generally choose the grease, because it adheres to the ability not run off in the part because of terrestrial gravity. Must know under what temperature the grease will lose this kind of ability. The attitude of never flowing of grease gets the attitude of flowing, the transition in qualitative optics is difficult to confirm through the way that the naked eye is observed, so change the temperature of the attitude into flowing on the attitude of never of the direct measurement flowing of lubricating grease. This temperature is named the drop point. The change on this kind of state is a characteristic of the grease with soap group thickening agents, as to the group thickening agent grease of non- soap, perhaps there is not a change of this kind of state, but and the oil appearing is dripped and fallen.

There is no absolute physical meaning in the drop point because its number value is different because the apparatus is different from heating speed. Can roughly understand classification, component and its approximate upgrade of using the temperature of the grease,etc. from the determination of the drop point. It melt since soap come it watch,soap group the consumption temperatures of grease should drop point 20-30 ℃ s subs low. For example, the drop point of calcium base grease is 75-95 ℃, it is probably 50-70 ℃ that it uses the temperature. The table lists the grease and drips dot and and uses the general relation of temperatures by 4-1, its low-temperature lower limit mainly depends on the base oil chosen.

The national standard GB/ T4929-85 is the mensuration of the grease drop point, and ISO/ DP2176 equivalent. GB/ T3498-83 is that the grease looks for some mensuration of temperature range disease.

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