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Can We Help You

Can We Help You We welcome queries from readers on any subject allied to Lubrication, whether it be from manufacturers or users of oils and greases. Technical and practical problems will be answered by experts. Questioners' names and addresses will not be published unless we are requested to do so, but they must be included with questions, for our own information and as a mark of good faith; such infor­ mation will be treated in strict confidence. ADDITIVE FOR BLACK GREASE metal, which only breaks down when boiling of the quenching oil takes place. At this point the cooling We should be glad of your advice regarding the most rate with mineral oils is most rapid and its time efficient additive for incorporation in a black grease for sequence is dependent on the volatile components. the lubrication, by Tecalemit system, of plate mill As the temperature drops heat transfer is effected by bearings. The bearings are of white metal and are convection and the cooling rate is much slower. water cooled. Theoretically one could promote rapid breakdown The lubrication requirements of such bearings, so of the vapour envelope by th e introduction of kerosene dispensed, are sufficiently critical to call for every into the quenching oil but this, obviously, is impract­ care in the composition and properties of the grease icable and the only thing that can be done is to assist used. the convection process and, by maintaining a more Firstly, it must be of a consistency that will rapid rate of heat transfer, improve the cooling rate. guarantee trouble-free feed over the whole tempera­ The convection rate is somewhat dependent upon oil ture range likely to be encountered in the particular viscosity and since oil thickens rapidly under the plant. This, in effect, is dependent on the apparent oxidation conditions experienced in quenching, any viscosity and may not wholly be defined by a simple method of preventing oil thickening is an advantage. penetration measurement. Oxidation inhibitors of the type used in motor oils are Secondly, the grease must be thermally stable, used fairly successfully for this purpose and the showing neither undue stiffening or softening in use, additional introduction of a detergent or dispersant and once more, of the correct viscosity to give an additive will help to minimise oil thickening by adherent film under the shear rates encountered in peptising the decomposition products as they are the bearing itself. The composition will also be formed. Additionally the introduction of a detergent influenced by possible contamination with water. compound which has high wettability properties is an These criteria may normally be met by a soft, advantage, since this wets the metal preferentially stable, lime soap product compounded of a heavy and ensures rapid heat pick up. black oil, but the possible shock loading experienced A detergent additive alone is not so successful as makes further fortification desirable. a combination of detergent and antioxidant, since the Any so-called "film strength" additive needs very oil decomposition products produced on oxidation careful selection. This is because, as such bodies must have an insulating effect and it is therefore preferable necessarily be polar ones, they can quite easily lead to reduce these to a minimum by the use of a suitable to serious modification in the basic properties of the antioxidant. grease. Thus, addition of many such materials As a general rule therefore detergent/antioxidant might easily produce actual deterioration rather than combinations can be used but it is preferable to select improvement. An unfortified grease that is stable the additive according to the type of base stock, since and feeds positively is preferable to a fortified one the oxidation characteristics of oils vary so widely. tha t may soften or stiffen in use. Our experience indicates tha t the most satisfactory from all aspects are metal soaps, other than the primary one used for actual bodying of the grease fourt h world itself. In this connection lead oleate, or lead naph- thenate have been employed with success. petroleu m congress QUENCHIN G OILS The Fourth World Petroleum Congress is to be held in Rome in June 1955, and the provisional We have received further enquiries from subscribers programme states that the papers will be divided into with reference to additives for the treatment of accelerated nine sections as follows:— (1) Geology and Geo­ quenching oils, and we publish the following comments physics (2) Drilling and Production (3) Oil Processing on the subject. (4) Production of Chemicals from Petroleum (5) Since rapid heat transfer and cooling rate are the Composition of Petroleum (6) Utilization (7) Con­ most important characteristics of quenching media the struction of Equipment, Materials, Corrosion (8) vaporisation of mineral lubricating oils play an Transport, Storage and Distribution (9) Economics, important role in their application to this problem. Statistics, Education and Training. Lubricants will I t is well known that when quenching metal at high be discussed under Utilization and probably under temperatures the initial cooling rate is low as a result several sub-headings in other groups. of the formation of a vapour envelope round the 36 Scientific LUBRICATION June, 1954 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Industrial Lubrication and Tribology Emerald Publishing

Can We Help You

Industrial Lubrication and Tribology , Volume 6 (6): 1 – Jun 1, 1954

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0036-8792
DOI
10.1108/eb052281
Publisher site
See Article on Publisher Site

Abstract

We welcome queries from readers on any subject allied to Lubrication, whether it be from manufacturers or users of oils and greases. Technical and practical problems will be answered by experts. Questioners' names and addresses will not be published unless we are requested to do so, but they must be included with questions, for our own information and as a mark of good faith; such infor­ mation will be treated in strict confidence. ADDITIVE FOR BLACK GREASE metal, which only breaks down when boiling of the quenching oil takes place. At this point the cooling We should be glad of your advice regarding the most rate with mineral oils is most rapid and its time efficient additive for incorporation in a black grease for sequence is dependent on the volatile components. the lubrication, by Tecalemit system, of plate mill As the temperature drops heat transfer is effected by bearings. The bearings are of white metal and are convection and the cooling rate is much slower. water cooled. Theoretically one could promote rapid breakdown The lubrication requirements of such bearings, so of the vapour envelope by th e introduction of kerosene dispensed, are sufficiently critical to call for every into the quenching oil but this, obviously, is impract­ care in the composition and properties of the grease icable and the only thing that can be done is to assist used. the convection process and, by maintaining a more Firstly, it must be of a consistency that will rapid rate of heat transfer, improve the cooling rate. guarantee trouble-free feed over the whole tempera­ The convection rate is somewhat dependent upon oil ture range likely to be encountered in the particular viscosity and since oil thickens rapidly under the plant. This, in effect, is dependent on the apparent oxidation conditions experienced in quenching, any viscosity and may not wholly be defined by a simple method of preventing oil thickening is an advantage. penetration measurement. Oxidation inhibitors of the type used in motor oils are Secondly, the grease must be thermally stable, used fairly successfully for this purpose and the showing neither undue stiffening or softening in use, additional introduction of a detergent or dispersant and once more, of the correct viscosity to give an additive will help to minimise oil thickening by adherent film under the shear rates encountered in peptising the decomposition products as they are the bearing itself. The composition will also be formed. Additionally the introduction of a detergent influenced by possible contamination with water. compound which has high wettability properties is an These criteria may normally be met by a soft, advantage, since this wets the metal preferentially stable, lime soap product compounded of a heavy and ensures rapid heat pick up. black oil, but the possible shock loading experienced A detergent additive alone is not so successful as makes further fortification desirable. a combination of detergent and antioxidant, since the Any so-called "film strength" additive needs very oil decomposition products produced on oxidation careful selection. This is because, as such bodies must have an insulating effect and it is therefore preferable necessarily be polar ones, they can quite easily lead to reduce these to a minimum by the use of a suitable to serious modification in the basic properties of the antioxidant. grease. Thus, addition of many such materials As a general rule therefore detergent/antioxidant might easily produce actual deterioration rather than combinations can be used but it is preferable to select improvement. An unfortified grease that is stable the additive according to the type of base stock, since and feeds positively is preferable to a fortified one the oxidation characteristics of oils vary so widely. tha t may soften or stiffen in use. Our experience indicates tha t the most satisfactory from all aspects are metal soaps, other than the primary one used for actual bodying of the grease fourt h world itself. In this connection lead oleate, or lead naph- thenate have been employed with success. petroleu m congress QUENCHIN G OILS The Fourth World Petroleum Congress is to be held in Rome in June 1955, and the provisional We have received further enquiries from subscribers programme states that the papers will be divided into with reference to additives for the treatment of accelerated nine sections as follows:— (1) Geology and Geo­ quenching oils, and we publish the following comments physics (2) Drilling and Production (3) Oil Processing on the subject. (4) Production of Chemicals from Petroleum (5) Since rapid heat transfer and cooling rate are the Composition of Petroleum (6) Utilization (7) Con­ most important characteristics of quenching media the struction of Equipment, Materials, Corrosion (8) vaporisation of mineral lubricating oils play an Transport, Storage and Distribution (9) Economics, important role in their application to this problem. Statistics, Education and Training. Lubricants will I t is well known that when quenching metal at high be discussed under Utilization and probably under temperatures the initial cooling rate is low as a result several sub-headings in other groups. of the formation of a vapour envelope round the 36 Scientific LUBRICATION June, 1954

Journal

Industrial Lubrication and TribologyEmerald Publishing

Published: Jun 1, 1954

There are no references for this article.