R A T I O N A L I Z A T I O N OF TUBE P R O D U C T I O N

A . Z . K o m a r o v s k i i UDC 621.774

Increased effectiveness of industrial production is a necessary prerequisite of faster amort iza t ion and rep lace- ment of obsolete production plants by new and more modern equipment . Any branch of industry can develop by two paths: the extensive, i . e . , by increasing the volume of human and mate r ia l resources in use; and the intensive, by raising production volumes through technologica l reequipment , improved ut i l iza t ion of plants and mater ia ls , and by raised productivi ty of labor.

In the tube industry the former tendencies are strong, so that intensif icat ion of production is of great sig- nif icance here. Thus, with the vast resources being expended on the development of the tube industry, ex t remely l i t t l e is being invested in sections for improving tube qual i ty , in heat t rea tment and finishing plant, and in other technology which would permi t a substantial reduction in meta l consumption.

In the USSR great a t tent ion is being paid to improving the range and qual i ty of production and to the output of

economic and l ightened profiles. However, the range of cer ta in types of tubes is at present more restricted than in the USA. For example , the min imum wall thickness of hot - ro l led seamless tubes 60 mm diameter and below is 2-2.5 mm in the USA (on the new continuous mil ls) , but ~ mm in the USSR. The specif icat ion for 30-102 miI1 at the Pervoural ' New Tube Works envisages a min imum wall thickness of 1.75 mm, but owing to design defects the tubes rol led on the mi l l have a wail thickness not less than 3 ram.

Up to the present t ime the tube industry has not mastered the production of profiled tubes of a l l the configura-

tions and dimensions st ipulated by technica l specif icat ions. The exper ience of Soviet and foreign industry confirms that more f lexible adapta t ion of the range of roi led products and tubes to the parameters of the finat meta l products yields considerable economies both in me ta l and machining and in expenditure of mi l l and labor t ime . Inadequate quali ty and the restrictions of the range lead to Iarge tube consumption in branches of the domestic economy, where

consumption is in any case heavy because of defec t ive component production. Thus, in the Dnepropetrov Agricul- tural Machinery Works components (nuts) for beet -harves t ing combines are made from roiled tubes 83 X 19 mm

giving a recta! use coeff ic ient of 0.36, and from drawn tubes 48 x 9 m m with a coeff ic ient of 0.42. At present

much work is being done on the introduction of e l e c - TABLE 1. New Wholesale Price List, rubles/ ton*

Tubes

Tube size, mm rolled drawn e lec t r i ca l ly welded

25 X 2.5 6.361" 3.881"

32 X 2.5 7.30 t 3.51

38 x 2.5 8.241" 4.051"

51 x 2.5 9.66 I" 5.35f

57 x 3.5 231 169

76 x 3.5 218 170.9

89 x 3.5 210 170.7

102 x 3.5 191 169.4

102 x 4 183 167.5

108 x 4 181 167.9

*Annealed e l ec t r i c a l l y -we lded tubes incur a premium of 20 rubles / ton. Roiled and drawn tubes are supplied unhea t - t rea ted .

1"In rubles/10 m.

t r ica l ly welded tubes to replace the seamless (rolled, drawn, th in-wal led seamless and pipel ine) .

To make better use of the capac i ty of the e l ec t r i ca l ly welded tube mills producing tubes of 114-426 mm d i a m e t e r , the nomenclature of pipel ine tubes has been split in two from 1968: seamless and e l ec t r i ca l ly welded. This will permit a more accurate determinat ion of their consumption and of the need to

build new e lec t r i ca l ly welded tube mi l l s . But the greatest effect on the domestic economy results from

the rep lacement of th in-wal led seamless, drawn and rol led tubes by e l ec t r i ca l ly welded. Thus, solely owing to the difference in cost of these tubes the domest ic economy wit1 achieve vast savings (see Table 1).

Analysis of Soyuzglavmeta l orders showed that the construction organizations and mechanica l engi - neering undertakings use a large quanti ty of th in- wai led seamless drawn and rol led tubes with dimensions

Gosplan SSSR. Translated from Metal lurg, No. 1, p. 34, January, 1969.

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similar to those of the tubes envisaged by the range of electrically welded tube mills, working with radiofrequency currents and equipped with hydraulic presses and heat-treatment plant.

Since drawn, rolled, and electrically welded tubes have closely similar characteristics, 19,000 tons of rolled, 5,500 tons of drawn, and more than 10 m meters of thin-walled seamless tubes will be replaced in the very near future by electrically welded, However, extension of the sphere of use of electrically welded tubes requires an extension of the range available, improvement of production technology, elimination of the internal bead, and guaranteed tube quality indices.

It should be noted that the production of electrically welded tubes requires less plants, so that specific capital outlays and running costs are reduced. Thus, one ton of resistance-welded tubes produced on 51-152 miil requires half as much equipment (by weight) as the production of seamless tubes on 30-102 continuous mili; consequently, specific capital outlays are reduced by 43% and running expenses by 8.7% At the same time the ratio of tube wall to diameter is 4-5% in seamless tubes, but 2% and !ess in welded tubes, which yietds considerable metal savings.

Study of the structure of tube demand to determine replaceability, replacement of deficient and expensive types of tubes by better and cheaper types permit not only the achievement of economics in the tube-consuming branches of industry, but also reduction of the capital investment and running costs in the tube industry.

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