INCREASING
THE OPERATING
A. I. K a r m a z i n
and
EFFICIENCY
S. A. G a p o n e n k o
OF E Q U I P M E N T UDC 669.1.002.5
The trouble-free operation of equipment and high output are vital factors in completion of the Ninth FiveYear Plan assignments; they are guaranteed by precise and strict application of the scheduled maintenance system and proper organization of preventive work, by increasing the periods of equipment operation between overhauls, and by reducing the time required for running repairs and major overhauls. Increases in the periods of equipment operation between overhauls are achieved by skitlful operation and by strengthening components, using various methods: heat treatment, hard facing, replacement of materials, effective choice of steels, design changes, use of alloy steels, application of coatings, etc. A component strengthening group was established at our plant in 1961, attached to the chief mechanical engineer's department, and a laboratory was set up for the purpose in 1965, for coordination and planned work to find components subject to rapid wear and increase their service life. The functions of the laboratory include the following: scrutiny of shop orders; defining the method and coordinating the technical specifications for component strengthening; drawing up a list of components according to forms of strengthening required; making amendments to master drawings in the shops;issuing the orders relating to component manufacture and heat treatment; drawing up process charts and control systems jointly with the heat treatment department; identification of components with low strength in order to increase their service life; active participation in improving existing methods of component treatment and in the adoption of advanced methods of treatment; and research, enlisting scientific-research and teaching institutions when necessary. The laboratory works closely with the production shops, the manufacturing shops, and the plant central laboratory. The components which restrict production are identified at extended production-shop mechanical engineering services conferences held jointly with the strengthening laboratory and with representatives of the chief mechanical engineer's department. Thus in 1973, 640 equipment items weighing 488 tons were identified which had previously not been strengthened or not strengthened sufficiently. In 1973 the chief mechanical engineer's department strengthened and reconditioned 10,270 tons of components, 1713 tons by heat treatment, 1452 tons by hard facing, and 7105 tions of exchange equipment (molds, stools, trumpets, pallets, and cars). The saving obtained by componenthard facing was 630,000 rubles. Refractory hard facing materials are the most effective; their use has increased the service life of components by several times, and sometimes by several tens of times. Thus the hard facing of roller table roller necks, charging box car axles, and balance beams using PPaKh2V8 compacted-powder wire has enabled our plant to replace tin bronze bushes in the friction couples by steel bushes. Investigations have established that the coefficient of friction in steel on steel (hard-faced neck and hardened steel bush) with lubricant is equal to the coefficient of friction in a s t e e l - b r o n z e couple; in dry friction it is much lower. A steel couple with a surface finish of V7 and a hardness of 42 Rockwell C operates for prolonged periods without substantial wear both with lubricant and under conditions of semidry friction at high dust levels and high temperatures. As a result of this, they are saving about 70 tons of tin bronze every year in the plant main shops alone. Most of the components can be reconditioned severai times after the strengthening layer has worn out. Hard-facing with wear-resistant materials has not only given substantial increases in component life, it has made it possible to dispense with costly steels in a number of instances. Composite alloys and hard-facing materials with complex-alloy hardeners have become widespread at the plant in recent years. A process for tungsten carbide hard facing in the furnace using a cupro-nickel bonding agent, etc., has been assimilated. Makeevka Metallurgical Plant. Translated from Metallurg, No. 11, pp. 57-59, November, 1974. 9 1975 Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, micro. filming, recording or otherwise, without written permission of the publisher. A copy of this article is available from the publisher for $15.oo.
875
The application of refractory compounds to surfaces subject to wear using electric sparks is extremely effective. A section for electric spark alloying of components using VK6, VKS, T15K6, etc., alloys has been organized at the plant. Plastics (capron, caprolon, polyethylene) have shown themselves to be good replacements for nonferrous metaIs, especially as rolling-mill spindle-joint bushes. Cast stone is widely used to protect surfaces from abrasion. The use of alloy steels instead of carbon steels is effective, but their widespread adoption is made difficult because the Ukrainian SSR Ministry of Ferrous Metallurgy does not allocate funds to the plants for use on alloy metal for repairs. For example, in 1972 only 307 tons of the 1320 tons of alloy steels applied for were received. Modernization and reconstruction of equipment during major overhauls and the testing and adoption of new techniques also help to lengthen the periods between overhauls. In the period 1961-1972 the chief mechanical engineer's department has carried out 39 research projects, independently and jointly with scientific-research institutes; the results of 36 of these have been adopted into production, giving a total saving of 533,400 rubles. This has made it possible to extend the period between blast-furnace and rolling-mill overhauls by 1.5-2 times in recent years. Unit output can also be increased by reducing the time required for running repairs and major overhauls; this is achieved by proper organization, by drawing up operations schedules for construction and erection work in all sections, by using advanced methods of maintenance, by mechanization, by careful preparation of the equipment e m ploying assembly of subunits and regulation of equipment to be exchanged prior to the overhaul, and by on-the-spot solution of technical problems during preparation and during the overhaul period. Thus major overhauls of basic units at the plant were completed 18 days ahead of the planned time in 1971, 15 days ahead in 1972, and 50 days ahead in 1973. The problems of increasing the life of equipment, reducing the proportion of manual labor, increasing unit output, and improving product quality are being solved with the active involvement of the broad spectrum of working people in rationalization and innovation work. Every fourth employee at the plant is a rationalizer. In 1973, 7859 rationalization proposals were submitted; 6604 of these have been adopted, giving a saving of 4,$88,000 rubles. Plant equipment operation can be improved along the following lines: planned reconstruction of units and subassemblies; improvement of the scheduled maintenance system; the use of advanced strengthening methods; adoption of new hard facing materials and steels; mechanization of repair work; and specialization by maintenance personnel and improvements in their level of skill. Further increases in the productivity of maintenance personnel and in unit operating efficiency involve the necessity for cooperation and specialization in the production of components and the centralization of maintenance services within the framework of the industry. Centralized manufacture and repair of blast-furnace charging equipment is already a requirement today. Thus, during the past three years in which our plant has begun to obtain charging equipment from the Zhdanov Heavy Engineering Plant, the service life of the equipment has begun to increase, averaging 10.6, 11.9, and 12.8 months, respectively, in 1971, 1972, and 1973, in spite of tightening up in the blastfurnace process parameters. The centralized manufacture and supply of running wheels for electric bridge cranes has long been essential. A series of measures have been implemented at the plants to increase the service life of these wheels (selection of steels, various methods of strengthening, unification, and so on). This has undoubtedly had some results, but the rate of running wheel usage is still high: Year New wheels manufactured Wheels reconditioned
"1969 1970 1971 1972 1973 586 543 469 426 455 448 426 540 324 308
If the service life of bridge-crane running wheels is to be further increased, they must be manufactured by rolling and with the appropriate heat treatment. A specialized rolling production proces should be organized for this purpose. Cooperation between metallurgical plants in spare-part manufacture must be the preliminary step on the road to widespread specialization in the business of improving component quality, reliability, and longevity. The prerequisites for this are, on the one hand,.the fact that plants acquiring the equipment for various forms of treatment and methods of strengthening are often in no position to employ it fully; o n t h e other hand, a metallurgical plant is in no position to maintain high-quality production of such an enormous range of components. For example, e l e c trolytic boronizing should be carried out within the framework of a regional or group processing section. Blades for hot and cold cutting of metal cause bottlenecks at atl plants, because their production to modern standards requires a high degree of specialization and complicated equipment. The most effective way is to centralize their manufacture. Blade usage at our plant (without the rail joint section) is as follows: 876
Year No, of blades
1968 1969-1970 1971 1972 1973 1618 1468 1503 1915 1740 1770
The following are essential in increasing productivity in the maintenance services in the metallurgical industry. 1. Unification of the equipment of basic units in the industry, replacement of obsolescent equipment, and compilation of obligatory equipment modernization plans. 2. Unification and standardization of crane equipment and of its components and subassemblies; establishment in the maintenance trust system of boards or sections for the repair of lifting machinery. 3. Compilation of a plan for the development of maintenance resources in the industry enterprise by enterprise, with allowance for specialization and cooperation among the plants. 4. Further centralization of plant maintenance services. 5. Preparation of unified plans for the supply of metal to the maintenance services, with a wide range of alloy steels and hard facing materials. 8. Supplying the maintenance services with high-output equipment for the manufacture of spare parts. 7. Enterprise specialization in the manufacture of specific standard equipment. 8. Working out proper staffing for the maintenance services. 9. Centralization of maintenance services within the framework of the industry. These will increase the efficiency of equipment in accordance with the growing demands of enterprises in the metallurgical industry.