Iron and Steel: The Elasticity, Extensibility, and Tensile Strength of Iron and Steel

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J. Murray, 1869 - Iron - 171 pages

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Page 157 - From these experiments the translator is led to draw the following conclusions : — 1. That for such iron as is usually employed for rails in the three principal rail-making countries (Wales, France, and Belgium), the breaking strain, as tested by sudden blows or shocks, is considerably influenced by cold ; such iron exhibiting at 10° F. only from onethird to one-fourth of the strength which it possesses at 84° F.
Page 71 - The limit of elasticity, the absolute strength, and the extensibility are to a great extent dependent, in both iron and steel, on the mechanical treatment to which the material has been submitted, and on the temperature to which it has been exposed, either during working or subsequently. By cold-hammering, cold-rolling, and other forms of mechanical treatment applied at a low temperature, both the limit of elasticity and the absolute strength are increased ; while by the same treatment the extensibility...
Page 114 - From these experiments on tension at widely different temperatures we have thus found : — 1. That the absolute strength of iron and steel is not diminished by cold, but that even at the lowest temperature which ever occurs in Sweden, it is at least as great as at the ordinary temperature (about 60° Fahr.).
Page 157 - F. 2. That the ductility and flexibility of such iron is also much affected by cold; rails broken at 10° F., showing on an average a permanent deflection of less than one inch, whilst the other halves of the same rails, broken at 84° F., showed a set of more than four inches before fracture.
Page 122 - The modulus of elasticity for steel and iron on flexion may, for practical purposes and without committing any considerable error, be generally assumed equal to that on traction. It is diminished by permanent deflection, but may be restored by heating, especially if raised to a red heat.
Page 62 - ... per cent., as his bars had a thickness of only 0'8 to 1'7 line. The third power of this thickness enters into the formula for calculating the modulus of elasticity by flexion, and therefore an error in measurement of 0'00058 inch, which for the thinner bars is more than -^ per cent, of their thickness, causes an error of upwards of 1J per cent, in the modulus.
Page 112 - That the modulus of elasticity in both steel and iron is increased on reduction of temperature and diminished on elevation of temperature, but that these variations never exceed 0.05...
Page 102 - As seen, however, from Table VII., there is generally no great difference between the diminutions of specific gravity •when the fracture by extension was performed at different degrees of temperature. 7. Experiments on the Modulus and Limit of Elasticity in Iron and Steel at different Temperatures : Description of Apparatus employed. Experiments have also been made in order to determine in what manner the position of the limit of elasticity, and the value of the modulus of elasticity in iron and...
Page 111 - That the strength of iron and steel is not diminished by cold, but that, even at the lowest temperature which ever occurs in Sweden, it is at least as great as at ordinary temperature (about 60° Fahr., 15° Cent.).
Page 30 - ... no perceptible permanent elongation, but are gradually increased, and are always allowed to operate for as many minutes as each additional weight is per cent. of the entire load, then the author regards as the ' limit of elasticity ' that load by which, when it has been operating by successive small increments, as above described, there is produced an increase in the permanent elongation which bears a ratio to the length of the bar equal to .01 (or approximates most nearly to .01) of the ratio...

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