COILS FOR CANS are fed into electrolytic tin­ning line at speed of up to 1,250 feet per minute. The new facility is the third built by Columbia-Geneva Division at U.S. Steel's Pittsburg Works. Current can be adjusted during line operation.

size tin cans. Pittsburg Works is a large producer of tin plate in the West. Output of the plant's two older electrolytic tin­ning lines has been a major factor in meeting increasing western requirements for packaging foods, beverages, and other products.

Equipment

T h e new installation is equipped with automatic closed-loop feedback controi systems to regulate and synchronize most of the line functions. Included are modu­lated loop controls, both magnetic and photoelectric, and regulators governing speed, edge position, tension, temperature, and plating current. All of the regulators are synchronized to the speed of the moving steel.

T h e line employs pin-hole detectors, radiation gauges for measuring steel and coating thickness, flow-line indicators, reflectivity devices for surface inspection, and sheet-classifying equipment. An im­portant factor in the quality control sys­tem is a series of memory devices. These automatically cause the cut pieces of tin plate to be placed in separate piles ac­cording to quality.

T h e control devices can operate with the ribbons of steel racing through the

NERVE CENTER for control system are these stainless steel panels on the third electrolytic tinning line at U.S. Steel's Columbia-Geneva Division Pittsburg Works. They flank the cleaning and coating tanks on the operating level. Operator is adjusting current.

l ine at speeds u p to 1,250 feet a minute . They provide a maximum degree of ac­curacy in quality control through a con­stant close measurement of the thickness of both the steel and the tin coating. T h e y assure uniformity of finish, accurate classi­fication, and exactness in counting and pil ing.

Production Innovations

Other innovations on the third elec­trolytic installation at Pittsburg include the use of germanium rectifiers for clean­ing and plating the steel, a fire detection system employing heat sensitive cable, and rectifier switching for varying plating capacity.

T h e "main floor" of the new Pittsburg t inning l ine is actually at mezzanine level, some 15 feet above the mill floor level. Designed to facilitate maintenance of the large amount of machinery built into the line below main-floor level, it eliminates the older electrolytic tinning lines maintenance problems, where much of the lower level machinery was located in less accessible basement areas.

Color coding provides greater safety, easy identification of specific kinds of equipment, contrast between moving parts and stationary machinery, and control of light for greater eye comfort. As insurance against error by a color-blind person, all vital valves and switches are marked with readable tags.

Processing Methods

Most of the steel used for tin plate pro­duction at Pittsburg comes from the Co­lumbia-Geneva plant at Geneva, Utah, in the form of hot-rolled steel coils.

In the initial operation at Pittsburg the steel is processed through one of two continuous pickling lines, where acid treatment removes the hard scale formed in hot rolling at Geneva.

At the entry end of the new electrolytic t inning line, the coils are placed on one of two uncoilers. Whi le one coil is being run through the line, another is placed in position on a second uncoiler, ready to be welded to the tail end of the run­ning coil. T o allow the line to continue running while the entry end stops for several seconds to permit welding of the next coil to the end of the coil in proc­ess, some 250 feet of uncoiled steel is accumulated in two 80-foot looping pits, 60 feet extending below the floor level and 20 feet extending above the floor.

T h e steel passes into electrolytic clean­ing tanks after which it is scrubbed with brushes and spray rinsed. It then passes through acid pickling tanks to prepare the surface for plating. T h e actual coating of the steel with tin takes place as the steel is passed at high speed through a series of electrolytic plating tanks. It carries a low-voltage charge of direct-cur-renj: electricity as it passes around con­ductor rolls moving from tank to tank. Bars of tin measuring 6 feet long and 2 by 3 inches thick are hung vertically in the tanks. As the steel passes between the rows of tin bars immersed in an acid electrolyte, the electric current draws the tin from the bars and deposits it on the surface of the steel.

T h e new Pittsburg facility has a plating capacity of approximately 100,000 am­peres. Precise controls regulate the am­peres in proportion to the l ine speed to give the desired amount of tin coating. A unique arrangement of electrical con­trols permits plating a heavier coating on one side of the steel than the other, as is required by some uses. Th i s so-called "differential coating" provides a heavier coating for the inside of cans when in­creased resistance against corrosion is necessary.

After the melt ing process, the coated steel is treated chemically to preserve its bright appearance and to provide a thin, dense oxide coating. Sprays remove any excess acid, and a thin film of lubricant is applied.

T h e finished tin plate from the new P-'ttsburg l ine is shipped to can manu­facturers either in cut sheets or in coil form. An innovation on the l ine is an extra uncoiling mandrel which will per­mit the shearing of coils previously made while other coils of tin plate are being produced. Shipment of electrolytic tin plate in coil form is a relatively new development in the industry.

T h e end use of most tin plate is the familiar tin can on the grocery shelf, which is actually more than 99 per cent steel and less than one per cent tin.

USS Nautilus Makes "Under-the-Ice" History

T h e recent epoch-making "under the ice pack" transpolar trip of the U. S. Navy's Nautilus drew high commendation from Government and civilian sources on behalf of the officers and crew of the submarine as well as the industries whose equipment contributed to the success of the venture.

"For the trip we were equipped with the most modern navigational equipment in the Fleet," commented Comdr. W. R. Anderson, commanding officer of the Nautilus, who was awarded the Legion of Merit for the expedit ion. Included among the navigational aids were gyrocompasses, automatic depth and course-keeping con­trols, a celestial altitude recorder, and an aircraft-type C-ll Gyrosyn compass sys­tem especially designed for use in polar regions, all developed by Sperry Gyro­scope Company, Division of Sperry Rand Corporation, Great Neck, N.Y.

T h e submarine's automatic depth and course-keeping controls may be compared roughly to the automatic pilots used on aircraft, enabling a "planesman" to make ultrafine adjustments in steering direction. T h e l ightweight compass system employs a technique which cuts random non-floated gyro drift 90%. These gyros, which the company calls "Rotorace" (Electrical Engineering, May 1958, pp. 471-72) are of particular importance in upper latitude explorations.

In a telegram to Westinghouse Electric Corporation, Pittsburgh, Pa., Comdr. Anderson praised the performance of the nuclear engine designed and developed for the Nautilus by that company's Bettis Atomic Power Division, working under

988 Of Current Interest ELECTRICAL ENGINEERING

the direction of and in technical co-opera­tion with the Naval Reactors Branch of the U. S. Atomic Energy Commission. Representative James Fulton of Pennsyl­vania, in a congratulatory message sent to Westinghouse, commented "As a member of the House Foreign Affairs Committee and of the new Select Committee for Ex­ploration in Astronautics and Space I am strongly recommending . . . to Dr. James R. Killian, the President's Scientific Ad­visor as well as to the Advanced Research Projects Agency of the Department of Defense that the Westinghouse atomic and nuclear team be kept intact and its fine accomplishments be broadened into research and development on nuclear engines and power for space vehicles and intercontinental ballistic missiles."

"Hot" or "Cold" Shoot Used in Acceleration Test

From a dead stop, the Lockheed X-7 missile surges forward at an acceleration that would crush a body under two tons of weight, hits top speed, then slams to a stop equivalent to a 60 mph head-on crash into a solid brick wall. All this in only 0.04 of a second—and a scant 2 feet of travel distance. Thi s is the kind of pun­ishment modern missiles, with their deli­cate and precision parts, must withstand if they are to perform properly.

T h e "G-Shooter," a special device devel­oped by the Lockheed Missile Systems Division's engineers, puts the missiles through a rugged ground test of electronic equipment and systems before launch high into the upper atmosphere to flight-prove new and giant ramjet engines.

T o conduct the test, the X-7 is mounted on the rails of the G-Shooter which blasts the bird to an 18 g acceleration—18 times the force of gravity—to simulate the fan­tastic drive when the missile is rocketed to a sudden faster-than-sound speed sec­onds after launch. T h e test gives Lock­heed engineers a realistic look at how the many instruments and electronic systems in the missile will stand the tremendous shock of the rocket boost needed to bring the X-7 to a speed where its ramjet en­gine takes over.

Set for a test run, the X-7 rests on the G-Shooter's rails while a pressure of 2,100 pounds per square inch (psi) is built up in a cylinder containing a piston.

T h e pressure is released with a deafening roar, and the piston flashes forward, push­ing the missile at breakneck speed down the steel ribbons.

Eight bands of nylon webbing are strung under the rails to act as brakes and to keep the bird from flying off the shooter as it hits a speed of 23 feet per second in only 6 inches. Four of the webs stretch to their limits, absorbing the tre­mendous shock, then snap as planned to prevent rebound. T h e remaining four are there as a safety factor.

T w o techniques are used in the tests, it was explained, depending upon the mis­sile model or system to be checked out. One is the "hot" shoot during which all of the electronic systems are operating and sending radio signals to monitoring consoles nearby. T h e other is the "cold" shoot without the systems running and where the missile is taken into the shop for a system checkout. T h e cold shoots are used for those birds whose systems have been through the punishment before, while the hot shoots are given missiles which have design changes, new systems, or new major components. In either case, the data is carefully analyzed and the trouble spots pinpointed before the mis­sile is turned loose for flight.

Once past the g test and other final checks, the X-7 is air-launched from a B-50 over the desert range, slashing a vapor trail high in the New Mexico sky on another test of the powerful ramjet engines which will power some of the na­tion's new defense weapons.

Heliostat Keeps Furnace Tracking Sun

Man has taken a lesson from sunflowers to help h im push back the frontiers of science by developing a solar furnace equipped with a sun-tracking heliostat to keep the furnace pointed at the sun throughout the day.

Working on the principle of a sun­flower, which is reputed to keep its face pointed constantly at the sun, the helio-stat-equipped solar furnace was designed and built by missile engineers in General Electric's Missile and Ordnance Systems Department, Philadelphia, Pa.

Installed in the department's Aero-sciences Laboratory, where high-tempera­ture studies are conducted with many

SUPER ACCELERATION is achieved by this Lockheed X-7 missile (said to be the fastest and highest flying air-breathing missile in the free world) as it blasts the scant dis­tance of 2 feet along the rails of the spe­cially designed " G -Shooter" at Holloman Air Force Base Missile Development Center. Details are still classi­fied.

Future Meetings of Other Societies Illinois Institute of Technology

Conference on Radio Interference Re­duction, sponsored by Armour Research Foundation & U. S. Army Signal Engi­neering Labs, Oct 1-2, Museum of Science 8c Industry, Chicago, 111. S. I. Cohn, Elec Engg Research Dept, ARF of IIT, 10 W 35 St, Chicago 16, 111. 5th Annual Computer Applications Symposium, Oct 29-30, Morrison Hotel, Chicago, 111. Frederick Bock, Elec Engg Res Dept, ARF of IIT, same.

The Institute of Radio Engineers Symposium on Extended Range & Space Transmission, joint Geo Wash­ington U, Oct 6-8, Lisner Auditorium, GWU, Washington, D. C. Harry Fine. 1233 Valley Ave, SE, Washington 24, D. C. 4th National Aeronautical-Communica­tions Symposium, Communications Sys­tems, Oct 20-21, Hotel Utica, Utica, N. Y. R. C. Benoit, 138 Riverview Pkwy, Rome, N. Y. URSI Fall Meeting, Oct 21-22, Penn State U, University Park, Pa. S. Silver, U. S. Natl Coram URSI, 2101 Constitu­tion Ave, Washington 25, D. C. National Simulation Conference, Oct 23-25, Dallas, Texas. L. B. Wadel, 3905 Centenary Dr, Dallas 25, Texas East Coast Aeronautical & Navigational Electronics Conference, Oct 27-29, Lord Baltimore Hotel & 7th Regiment Ar­mory, Baltimore, Md. H. S. Rutstein, Eastern Assoc, 5612 Belleville Ave, Baltimore 7, Md. 1958 Electron Devices Meeting, Oct 30-Nov 1, Shoreham Hotel, Washington, D. C. R. K. Kilbon, RCA Labs, Prince ton, N. J

National Association of Corrosion Engi­neers

Northeast Region Conference, Oct 6-8, Boston., Mass. M. M. Jacobson, Water-town Arsenal Labs, Watertown 72, Mass. South Central Region Conference & Exhibition, Oct 20-24, Roosevelt Hotel, New Orleans, La. W. F. Oxford, Jr. Sun Oil Co, Beaumont, Texas.

Pennsylvania Electric Association, Fall Mee ing, Meter Committee, Oct 13-14, The Wentworth by-the-Sea, Portsmouth, N.H. J. B. Smith, c/oPEA Meter Meet-ine. above hotel. ASCE, Convention, Oct 13-17, New York. N.Y. D. Reynolds, ASCE, 33 W 39 St. New York 18, N. Y. American Institute of Mining, Metallur­gical, & Petroleum Engineers, Inc.

Southern Calif Petroleum Section Fall Meeting, Oct 16-17, Biltmore Hotel, Los Angeles, Calif. H. N. Appleton, AIME, 29 W 39 St, New York 18, N. Y.

Mining-Metallurgicals Mid-America Min­erals Conference, Oct. 23-25, Chase-Park Plaza Hotels, St. Louis, Mo. H. N. Appleton, AIME, same.

SMPTE, 84th Semiannual Convention, Oct 20-24, Sheraton-Cadillac Hotel, De­troit, Mich. C. E. Heppberger, 510 White Oak Dr, Naperville, 111. National Safety Council, 46th Annual Congress & Exposition, Oct 20-24, Chi­cago, 111. R. L. Forney, National Safety Council, 425 N Michigan Ave, Chicago 11, 111. American Vacuum Society, 5th National Vacuum Symposium, Oct 22-24, Sir Fran­cis Drake Hotel, San Francisco, Calif. C. B. Willingham, Mellon Institute, 4400 5th Ave, Pittsburgh 13, Pa. NSPE, Fall Meeting, Oct 22-25, St. Francis Hotel, San Francisco, Calif. J. A. Sontheimer, Calif Soc of Prof Engs, c/o above hotel. Electronic Industries Association

Radio Fall Meeting, Oct 27-28, Shera­ton Hotel, Rochester, N.Y. J. A. Caffiaux, EIA, 650 Salmon Tower, 11 W 42 St, New York 36, N. Y. Conference on Reliable Electrical Con­nections, Dec 2-4, Statler Hilton Hotel, Dallas, Texas. R. G. Roesch, 1068 S Clinton St, Syracuse 4, N. Y.

OCTOBER 1958 Of Current Interest 989