Document 5knaypJeJ028kgoxGYGLM686J

HOT WORKING OF METALS omy. Worn piston sleeves and sloppy ImkBge make the hammer hard to control and create a hazard Loose cylinder heads also are dangerous Frequent periodic inspection of every forg ing hammer will help ensure proper condi tion of all bolts, screws, keys, valves, and other parts which may be loosened by vibra tion Similarly, thorough periodic inspec tion and adjustment should be made of all parts of the treadle or pedal, dutch, and other operating mechanisms Worn or loose treadle linkage, motion arm, crank arm, and treadle can cause the hammer to go out of control These parts especially should be kept in good repair The dutch is a vital part of the forging press and must be kept m good condition if the press is to operate satisfactorily A broken spring or part which shows wear should be replaced at once. Lead casts Lead casts are taken m practically every conceivable manner m the forging industry. Casts should be taken only in an isolated area, if possible, where there is no likeli hood of interference from or injury to other workers The die impressions should be dry since hot metal that contacts water produces flying particles of molten metal Lead pots should be ventilated to the out side of the building Forging Upsetters The upsetter is a horizontal forging ma chine which forges hot bar stock, usually round, into a great many forms by a squeez ing action instead of impact blows, as m the case of forging hammers Although numer ous hazards are involved in the operation of an upsetter, the most senous problems are .encountered in changing the dies The entire machine should be completely enclosed, except for the feed area Heavy wire mesh or expanded or sheet metal rein forced with structural steel should be used Doors may be cut into the enclosure for servicing flywheel, brake, and other moving parts A guard should be installed over the operating pedal Safe operating conditions call for the area around the machine to be clean and clear of obstructions and litter It is especially im portant that the top ol the machine be dear of any objects, such as loose bolts, bars, nuts, or shuns, which might fall into it or from it The operator should shut off the power, lock the main power switch, and immobilize the flywheel before attempting to adjust dies, heading tools, stock gauges, or back stops Design of dies Dies and heading tools used in an upset ter or horizontal forging machine are not usually subjected to such severe abuse as are hammer dies A good grade of chrome, nickel, or molybdenum steel of the correct hardness is recommended for gnpper dies It is common practice m die shops when resmlang upset dies to use inserts rather than to cut down the dies The inserts most commonly used are made of a high chrome, nickel, or molybdenum steel with silicon added Tool steels with a vanadium and tungsten analysis are also used for inserts and head ers, but they must be selected to satisfy op erating conditions because of their limited use where coolants are employed Front or back stock gauges or backstops should be designed and located to serve the specific purpose and should not be a handi cap to the operator Special care should be taken to eliminate all hazards, especially pinch points Jobs which are abnormally heavy or which would create an unbalanced condition when running should be designed to employ balancing equipment to facilitate handling and reduce operator fatigue The gnp some times provided on upset die impressions should be sufficient to hold the stock secure ly, and should be checked after every run This precaution is important for the opera tor's safety, especially on jobs where the heading tool could push the stock bar out of the impression toward the operator. Setup and removal of dies At the end of a run and before further work is done, all skids of stock or forgings should be moved out of the area to allow as much room as possible when the dies are changed Die setters should not try to make a com plete setup dimensionally by measuring headers, strokes, and dies, without inching 27-45