| The people of Swit-zer-land were not always free and happy as they are to-day. Many years ago a proud tyrant, whose name was Gessler, ruled over them, and made their lot a bitter one indeed. One day this tyrant set up a tall pole in the pub... Read more of THE STORY OF WILLIAM TELL at Stories Poetry.com |  Informational.caPrivacy |
Steel MakingJudging The Heat Of SteelWhile the use of a pyrometer is of course the only way to hav... Steel For Chisels And Punches The highest grades of carbon or tempering steels are to be re... Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer For extremely high temperature, the optical pyrometer is lar... Annealing Method Forgings which are too hard to machine are put in pots with ... Suggestions For Handling High-speed Steels The following suggestions for handling high-speed steels are ... S A E Heat Treatments The Society of Automotive Engineers have adopted certain heat... Temperatures To Use As soon as the temperature of the steel reaches 100 deg.C. (... The Influence Of Size The size of the piece influences the physical properties obta... Corrosion This steel like any other steel when distorted by cold worki... Molybdenum Molybdenum steels have been made commercially for twenty-five... Quality And Structure The quality of high-speed steel is dependent to a very great ... Quenching The Work In some operations case-hardened work is quenched from the bo... Separating The Work From The Compound During the pulling of the heat, the pots are dumped upon a ca... Piston Pin The piston pin on an aviation engine must possess maximum res... Introduction Of Carbon The matter to which these notes are primarily directed is the... Lathe And Planer Tools FORGING.--Gently warm the steel to remove any chill, is parti... Gears The material used for all gears on the Liberty engine was sel... Properties Of Steel Steels are known by certain tests. Early tests were more or l... Hardening The forgings can be hardened by cooling in still air or quen... Preparing Parts For Local Case-hardening At the works of the Dayton Engineering Laboratories Company, ... |
MachineabilityCategory: ANNEALING Reheating for machine ability was done at 100 deg. less than the drawing temperature, but the time of soaking is more than double. After both drawing and reheating, the blanks were buried in lime where they remain, out of contact with the air, until their temperature had dropped to that of the workroom. For straightening, the barrels were heated to from 900 to 1,000 deg.F. in an automatic furnace 25 ft. long, this operation taking about 2 hr. The purpose of hot straightening was to prevent any stresses being put into the blanks, so that after rough-turning, drilling or rifling operations they would not have a tendency to spring back to shape as left by the quenching bath. A method that produces an even better machining rifle blank, which practically stays straight through the different machining operations, was to rough-turn the blanks, then subject them to a heat of practically 1,0000 for 4 hr. Production throughout the different operations is materially increased, with practically no straightening required after drilling, reaming, finish-turning or rifling operations. FIGS. 24 and 25.--Roof system of cooling quenching oil.] This method was tested out by one of the largest manufacturers and proved to be the best way to eliminate a very expensive finished gun-barrel straightening process. The heat-treating required a large amount of cooling oil, and the problem of keeping this at the proper temperature required considerable study. The result was the cooling plant on the roof, as shown in Figs. 24, 25 and 26. The first two illustrations show the plant as it appeared complete. Figure 26 shows how the oil was handled in what is sometimes called the ebulator system. The oil was pumped up from the cooling tanks through the pipe A to the tank B. From here it ran down onto the breakers or separators C, which break the oil up into fine particles that are caught by the fans D. The spray is blown up into the cooling tower E, which contains banks of cooling pipes, as can be seen, as well as baffies F. The spray collects on the cool pipes and forms drops, which fall on the curved plates G and run back to the oil-storage tank below ground. The water for this cooling was pumped from 10 artesian wells at the rate of 60 gal. per minute and cooled 90 gal. of oil per minute, lowering the temperature from 130 or 140 to 100 deg.F. The water as it came from the wells averaged around 52 deg.F. The motor was of a 7-1/2-hp. variable-speed type with a range of from 700 to 1,200 r.p.m., which could be varied to suit the amount of oil to be cooled. The plant handled 300 gal. of oil per minute. Next: Annealing Previous: Plant For Forging Rifle Barrels
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