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01-26-2015, 02:32 PM | #13 | ||||||
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Paul: Tensile strength is only a part of the equation for estimating bursting pressure. If the barrel is made of Decarbonized steel with a 60,000 psi tensile strength, that does NOT mean that it will withstand a 10,000 psi load by a factor of 6.
Barlow's formula P=2 S t / D P=Bursting pressure in psi. S=Tensile strength of material in tube wall. t=Wall thickness in inches. D=Outside diameter in inches. Barlow’s, and the other formula (Alger, Boardman and Lame), refer to a pipe capped at both ends with a static pressure (a pressure cylinder). Shotgun barrels are not designed to be pressure vessels as one end is open and the pressure rises and falls quickly. I've discussed this issue with Eldon and a metallurgical engineer and there is no working formula for open end tubes. Wallace H. Coxe, in "Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics" by E.I. du Pont de Nemours & Co. in 1931 published the following pressure/distance curve. He also cited a study in which a fluid steel barrel was cut to 9” and capped, then a series of progressively increasing pressure loads fired. The barrel cap was blown off and barrel burst at 5,600 psi. Comment in Sporting Guns and Gunpowders regarding the Proof House Report of 1891 http://books.google.com/books?id=inQCAAAAYAAJ&pg=PA16 "These experiments serve to show what a very large margin of strength there is in a good gun barrel, when ordinary charges are used. The (Damascus) barrels which gave way earliest under (the second phase destructive test) had withstood the strains of…about four times as great as the regulation proof; while the steel barrels (Siemens-Martin and English “Superior Barrel Steel”) were tested…with charges averaging nearly five times as much as the ordinary proof-charge. Although the steel barrels showed the greater amount of endurance, the strength of the Damascus was so much in excess of all ordinary requirements that no fear need be felt of their giving way when the work is properly done."
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01-28-2015, 04:55 PM | #14 | ||||||
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Drew, thanks for the info. I don't feel Remington would have made decarbonized steel barrels if they weren't safe for at least 8 to 10,000psi and that's within what most hand loaders stick to. I stay at 7700 which is around black powder pressures.
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01-28-2015, 08:44 PM | #15 | ||||||
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I agree Paul. "For Nitro Powder", and we know 3 1/4 Dram/40 grains DuPont Bulk Smokeless with 1 1/8 oz. shot ran about 8500 psi, and that would be a light load for the era
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01-28-2015, 09:57 PM | #16 | ||||||
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are the composition of decarbonized barrels differant than damascus or twist steel...i thought they was...i m thinking plain steel of parker barrels and decarbonized barrels about the same or the same thing..just wondereing.....charlie
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01-28-2015, 10:21 PM | #17 | ||||||
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That is what I thought too
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01-29-2015, 08:45 AM | #18 | ||||||
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Decarbonized steel is not a pattern welded laminate, it is "Bessemer process homogenous wrought iron" and was sourced from Remington Arms.
Pages 503 & 504 of "The Parker Story" state that Parker changed the name to "Plain Steel" as Remington was using the name "Decarbonized" on their newly introduced Model 1873 & 1875/1876 Hammer Lifter doubles. 889 guns were made with Decarbonized Steel barrels. From Fire-Arms Manufacture 1880 U.S. Department of Interior, Census Office "The earliest use of decarbonized steel or gun-barrels is generally credited to the Remingtons, who made steel barrels for North & Savage, of Middletown, Connecticut, and for the Ames Manufacturing company, of Chicopee, Massachusetts, as early as 1846. It is also stated that some time about 1848 Thomas Warner, a the Whitneyville works, incurred so much loss in the skelp-welding of iron barrels that he voluntarily substituted steel drilled barrels in his contract, making them of decarbonized steel, which was believed by him to be a novel expedient. The use of soft cast-steel was begun at Harper's Ferry about 1849. After 1873, all small-arms barrels turned out at the national armory at Springfield were made of decarbonized steel(a barrel of which will endure twice as heavy a charge as a wrought-iron barrel), Bessemer steel being used until 1878, and afterward Siemens-Martin steel." The tensile strength is a bit more than pattern welded barrel steel, about the same as AISI 1018 Low Carbon (Mild) Steel, a bit less than Whitworth fluid steel, and considerable less than modern 4140 chrome moly steel. The tensile strength could be increased by "cold rolling"; ie. Winchester Standard Ordnance “Rolled” Steel.
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01-29-2015, 05:33 PM | #19 | ||||||
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I have a very nice 1889 hammer Remington 1 grade with decarbonized steel. The chambers are a smidge shy of 2 3/4"...do not look cut out. Bores are very good, no pitting, dings or dents. Outside have age blemishes and blue loss still 60-70% little case color and some blemishes age. Wood is very nice with no damage, original plate and good shoot-able dimensions. I have fired target loads only but would not worry about game loads....would not try field loads unless I confirmed its strength to be up to it. SXS ohio
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02-02-2015, 11:12 AM | #20 | ||||||
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Ohio, I would bet dollars to donuts that over the life of your gun someone had shot just about everything in it, even magnum loads.
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