锻造技术英文文献和中文翻译(2)

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screw press.

The steelyard in Wyman-Gordon’s Danville plant, which Mr. Knott said could very well be the most expensive steel- yard in the world, was located inside the forge facility be- cause of the inclement midwestern winter. In comparing the “Danvil le process” with Wyman—Gordon’s pre- Danville practice, Mr. Knott started with billet preparation, in regard to which he said that the saw-cutting time, previously mea- sured in minutes, is now only a matter of seconds thanks to the use of carbide—tipped saws. Next in line is billet heating, which was previously fossil—fuel fired but is now exclusively done with induction heating (which made the cost and availability of electricity an important consideration in site selection). All other items of plant equipment were sized to match the capacity of the induction heating system. The plant features semiautomatic billet handling from one im- pression die to the next, using GE Manmate units with attendant operators to compensate for process deviation. Having reduced the size of the labor force through auto— mation, the remaining workers were safeguarded from the hostile environment traditional in forge shops. This was partly accomplished by replacing steam hammers with per- cussion screw presses and by housing the operator within a climate-controlled cab. Mr. Knott described the effect of all

APPLIED METALWORKING

these improvements on plant output and worker productiv- ity. In the early 1960’s, Wyman—Gordon employed a 25—man crew to turn out 18 crankshafts per hour. Their upgraded Harvey, Illinois, plant uses 16 men for an output of 62 parts per hour. The new Danville line is even more productive, turning out 75 parts per hour with a three-person crew.

The automatic die changing techniques recently imple— mented by General Motors’ Chevrolet Forge Division in support of their automated press systems were reviewed by

R.F. Donna. Covering a total manufacturing area of 635,000 square feet, the automated forge equipment in- cludes two 2500-ton retrofit presses, five Eumuco-Verson 2500-ton automated press systems, one additional 2500—ton automated press currently being installed, and a 3150-ton automated press system for diesel engine connecting rods. Five goals were established for the automated systems: con— trol of part quality, energy savings, cost reduction, reduced maintenance, and eliminating heat-treatment through air cooling. In reviewing performance relative to these goals, Mr. Donna cited a two pct reduction in scrap on V6 and V8 connecting rods (better quality control), a reduction in ener- gy cost by replacing steam hammers with presses, an overall cost reduction of 35 pct, and increased use of air cooling. According to Mr. Donna, all high-volume connecting rods have been designed and approved for hardening by rapid air cooling instead of a lengthy furnace heat—treatment. Per- formance relative to the goal of reduced maintenance, he said, has not been fully evaluated yet. Finally, Mr. Donna reviewed the Chevrolet forge plant’s improved die changing techniques and the time savings resulting therefrom. Manual die changing techniques, involving forklift trucks and hand tools, were initially upgraded to automatic track—bound die changers and power tools and, finally, to die changers in conjunction with hydraulic clamping/unclamping devices.

EOUIPMENT AND TOOLING

There were two presentations on forging equipment. The first was by J. Barbazanges of Interforge, a French company which was commissioned jointly by four major French die forging companies to operate a Soviet—built 65,000-ton hy- draulic press for aerospace forging applications. To set the stage for the subject matter, Mr. Barbazanges described some of the support equipment used in conjunction with the press, such as milling machines capable of sinking 20 x 10 foot cavities in die blocks weighing up to 160,000 pounds, an aluminum billet preheat furnace capable of processing 25,000 pounds per hour, an additional furnace for pre- heating steel and titanium at up to 260,000 pounds per hour, and two auxiliary preheat furnaces each capable of handling 70,000 pounds per hour, as well as furnace capabilities for heating a million pounds of tooling. Other support equipment include a 250-ton overhead crane, heat—treat