| There was once a shepherd-boy who kept his flock at a little distance from the village. Once he thought he would play a trick on the villagers and have some fun at their expense. So he ran toward the village crying out, with all his might,-- ... Read more of THE BOY WHO CRIED "WOLF!" at Children Stories.ca |  InformationalPrivacy |
Steel MakingHints For Tool Steel UsersDo not hesitate to ask for information from the maker as to t... The Care Of Carburizing Compounds Of all the opportunities for practicing economy in the heat-t... Preventing Cracks In Hardening The blacksmith in the small shop, where equipment is usually ... Case-hardening Treatments For Various Steels Plain water, salt water and linseed oil are the three most co... Preventing Decarbonization Of Tool Steel It is especially important to prevent decarbonization in such... Phosphorus PHOSPHORUS is an element (symbol P) which enters the metal fr... High-carbon Machinery Steel The carbon content of this steel is above 30 points and is ha... Suggestions For Handling High-speed Steels The following suggestions for handling high-speed steels are ... High-chromium Or Rust-proof Steel High-chromium, or what is called stainless steel containing f... Annealing In Bone Steel and cast iron may both be annealed in granulated bone. ... Nickel Nickel may be considered as the toughest among the non-rare a... Properties Of Steel Steels are known by certain tests. Early tests were more or l... Using Illuminating Gas The choice of a carburizing furnace depends greatly on the fa... Gas Consumption For Carburizing Although the advantages offered by the gas-fired furnace for ... Rate Of Cooling At the option of the manufacturer, the above treatment of gea... Refining The Grain This is remedied by reheating the piece to a temperature slig... Annealing Work With the exception of several of the higher types of alloy s... Judging The Heat Of Steel While the use of a pyrometer is of course the only way to hav... Temperature For Annealing Theoretically, annealing should be accomplished at a tempera... Instructions For Working High-speed Steel Owing to the wide variations in the composition of high-speed... |
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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