Evaluation method for thermal-oxidative stability of lubricants

 

(57) Abstract:

The invention relates to the field of study of lubricants used in the pressure treatment. Evaluation method for thermal-oxidative stability of lubricants includes heating the sample to a predetermined temperature in a porcelain crucible, determination of mass fraction of volatile and insoluble substances, with a mass fraction of volatile substances is determined by weighing the crucible before and after heating, and then the mass fraction of insoluble substances is determined on the walls and bottom of the crucible when it is weighed after removing them from the sample to obtain the insoluble residue. Improved reliability of estimation of the oxidative stability of lubricants due to the simultaneous determination of mass fraction of volatile and insoluble substances after heating the sample at a given temperature, and the ability to predict the contamination of the metal surface during the pressure treatment. table 1.

The invention relates to the field of study of lubricants and can be used in rolling mills for predicting the contamination of cold-rolled metal.

There is a method of assessing € RF N 2098812, CL G 01 N 33/30, publ. 10.12.97 bull. N 34). However, this method does not allow to evaluate the resistance of the oil to oxidation.

Known photometric method of assessing oxidative stability of lubricants (Kowalski B. I., Nazarov, G.: laboratory 1997. So 63. N 12 C. 16-17). The disadvantage of this method is the lack of quantitative measurement of thermostability.

The closest in technical essence to the present invention is a method of assessing oxidative stability of lubricants by determining mass fraction of volatile and insoluble substances (Turcan, I., Kuznetsov, C. P., Gvirtzman A. A. Lubricating and protective materials, M.: Transport, 1981, S. 47-48). However, this method does not allow to model the degree of contamination of the metal surface during the pressure treatment.

The technical task to be solved by the invention, is to increase the reliability evaluation of oxidative stability of lubricants.

This is achieved by simultaneously determined by the mass fraction of volatile and insoluble substances after heating the sample at a given temperature.

The method zakluchaetsa), which weighed on an analytical balance from 1.0 to 1.5 g of a lubricant.

The crucible is placed in a heat chamber, heated to a predetermined temperature, and maintain it 60-120 minutes After cooling, the crucible is weighed and determine the mass fraction of volatile substances. Then the rest of emulsol is drained, washed with crucible gasoline, it is dried in a heating Cabinet at 100oC to constant mass and calculate the mass fraction of insoluble substances formed on the sidewalls and bottom of the crucible, when it is weighed after removing them from the sample to obtain the insoluble residue.

To test the effectiveness of the proposed method was evaluated oxidative stability of various lubricants used in cold rolling of metal on pjatikletevoj mill "2030" JSC "NLMK" in Lipetsk). Was previously calculated average temperature in the deformation zone for this mill, which was 240oC. At this temperature and were tested lubricants. The results are given in the table.

From the data presented in the table it follows that the proposed method for 60-120 min allows to differentiate on the oxidative stability of different is the most pure metal was obtained using lubrication Quakerol 671 N", and the most dirty - lubrication "Renol-1".

Evaluation method for thermal-oxidative stability of lubricants, including heating the sample to a predetermined temperature, determining mass fraction of volatile and insoluble substances, characterized in that the heating of the sample to a predetermined temperature is carried out in a porcelain crucible, and the mass fraction of volatile substances is determined by weighing the crucible before and after heating, and then the mass fraction of insoluble substances is determined on the walls and bottom of the crucible when it is weighed after removing them from the sample to obtain the insoluble residue.

 

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