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Physical properties of materials: Compiled tables. I. Strengths and related properties of metals and certain other engineering materials
4z4
U.S.
BUREAU"OF STANDARDS NOTES.
[J. F. I.
smaller. However, even the largest number of repetitions was so small that failure in the steel would not have been expected at the time at which it did occur considering that the observed stresses were very low. Other factors than the intensity of the tensile and compressive stresses seem to have had a part in bringing about the early tension failure. All of the tension failures in the reinforcing bars occurred at sections where large cracks extended entirely across the section of the beam. It is possible that in some cases the bending at these cracks was sufficient to make the bending of the bar an important factor in causing failure. The slipping of bars at the ends, such as happened in one of the beams, would permit the opening of wide cracks and accentuate this tendency. The presence of the gage holes in the bars seems to have had some influence in hastening tension failure, but this influence was not very distinct. The quality of steel used for most of the reinforcement was poor and this would contribute to bringing about early failure. However, this alone would not account for the small number of repetitions of stress generally required in these tests to produce failure. After 7000 cycles of load the slip at the end of the bar in one of the beams was less than o.ooI in. ; that is to say, less than the amount which has been taken as the criterion of safe conditions based on tests of the bond resistance between concrete and steele Yet, after 400,000 cycles of load, the amount of slip had increased so much that failure by slipping of the bars seemed imminent. It seems that the intervention of tension failure at an unexpectedly small number of repetitions of load prevented the bond failure of this specimen. PHYSICAL PROPERTIES OF MATERIALS: COMPILED I. S T R E N G T H S AND RELATED PROPERTIES METALS AND CERTAIN OTHER ENGINEERING I~ATERIALS. 9
TABLES. OF
[ABSTRACT.]
THIS circular aims to present, in readily accessible form, the best available data on the strengths and related properties of metals, alloys, arid certain non-ferrous metals. Among the mate'~Circular No. ioI.
March, Ig;E.]
U. S. BUREAU OF STANDARDS NOTES.
415
rials treated are iron, carbon steels, alloy steels; wire and wire rope; semi-steel; aluminum, copper, and miscellaneous metals and their alloys; rope, rubber, leather, and woods. The tensile strength, proportional limit, percentage elongation in two inches, percentage reduction of area, Brinell and scleroscope hardness corresponding to a certain composition, density and method of preparation are shown in most cases for the metals and alloys. In addition, figures are shown in many instances for the compressive and shearing strengths, modulus of rupture and Erichsen value. • The circular also includes definitions of the properties treated and references to sources. EXPERIMENTS
ON
COPPER
CRUSHER
C Y L I N D E R S . I°
By Alexander I. Krynitsky.
[ABSTRACT.] T H E metallic cylinders, usually made of exceedingly pure copper or lead, employed for the measurement of pressure developed by the products of decomposition of powder in the testing of powder and ammunition, are known as crusher cylinders. On firing, the pressure of the gases shortens the cylinder longitudinally by means of the piston of the special apparatus used. The amount of this compression, in conjunction with the proper value taken from a previously prepared table of values showing the relation between the compressions and corresponding total sets of the length of each lot of cylinders, serves to determine the maximmn pressure of the products of decomposition. These copper cylinders are the subject of this investigation, which was carried out in I9I 9 by the Bureau of Standards in connection with the standardization of the crusher gage method for pressure testing of small arms, ammunition, and powder, and which consisted of a series of compressions of the annealed copper cylinders, one set having a mean length of o.4ooo in. and the others o.5ooo in., with a mean diameter of o.226o in. in the former and o.25oo in. in the later ones, on a standard Io,ooo-lb. Riehl6 testing machine. From the results of these investigations it appears that: I. The length of copper crushed cylinders decreases consider-
'" Technologic Paper No. 185.
U.S.
BUREAU"OF STANDARDS NOTES.
[J. F. I.
smaller. However, even the largest number of repetitions was so small that failure in the steel would not have been expected at the time at which it did occur considering that the observed stresses were very low. Other factors than the intensity of the tensile and compressive stresses seem to have had a part in bringing about the early tension failure. All of the tension failures in the reinforcing bars occurred at sections where large cracks extended entirely across the section of the beam. It is possible that in some cases the bending at these cracks was sufficient to make the bending of the bar an important factor in causing failure. The slipping of bars at the ends, such as happened in one of the beams, would permit the opening of wide cracks and accentuate this tendency. The presence of the gage holes in the bars seems to have had some influence in hastening tension failure, but this influence was not very distinct. The quality of steel used for most of the reinforcement was poor and this would contribute to bringing about early failure. However, this alone would not account for the small number of repetitions of stress generally required in these tests to produce failure. After 7000 cycles of load the slip at the end of the bar in one of the beams was less than o.ooI in. ; that is to say, less than the amount which has been taken as the criterion of safe conditions based on tests of the bond resistance between concrete and steele Yet, after 400,000 cycles of load, the amount of slip had increased so much that failure by slipping of the bars seemed imminent. It seems that the intervention of tension failure at an unexpectedly small number of repetitions of load prevented the bond failure of this specimen. PHYSICAL PROPERTIES OF MATERIALS: COMPILED I. S T R E N G T H S AND RELATED PROPERTIES METALS AND CERTAIN OTHER ENGINEERING I~ATERIALS. 9
TABLES. OF
[ABSTRACT.]
THIS circular aims to present, in readily accessible form, the best available data on the strengths and related properties of metals, alloys, arid certain non-ferrous metals. Among the mate'~Circular No. ioI.
March, Ig;E.]
U. S. BUREAU OF STANDARDS NOTES.
415
rials treated are iron, carbon steels, alloy steels; wire and wire rope; semi-steel; aluminum, copper, and miscellaneous metals and their alloys; rope, rubber, leather, and woods. The tensile strength, proportional limit, percentage elongation in two inches, percentage reduction of area, Brinell and scleroscope hardness corresponding to a certain composition, density and method of preparation are shown in most cases for the metals and alloys. In addition, figures are shown in many instances for the compressive and shearing strengths, modulus of rupture and Erichsen value. • The circular also includes definitions of the properties treated and references to sources. EXPERIMENTS
ON
COPPER
CRUSHER
C Y L I N D E R S . I°
By Alexander I. Krynitsky.
[ABSTRACT.] T H E metallic cylinders, usually made of exceedingly pure copper or lead, employed for the measurement of pressure developed by the products of decomposition of powder in the testing of powder and ammunition, are known as crusher cylinders. On firing, the pressure of the gases shortens the cylinder longitudinally by means of the piston of the special apparatus used. The amount of this compression, in conjunction with the proper value taken from a previously prepared table of values showing the relation between the compressions and corresponding total sets of the length of each lot of cylinders, serves to determine the maximmn pressure of the products of decomposition. These copper cylinders are the subject of this investigation, which was carried out in I9I 9 by the Bureau of Standards in connection with the standardization of the crusher gage method for pressure testing of small arms, ammunition, and powder, and which consisted of a series of compressions of the annealed copper cylinders, one set having a mean length of o.4ooo in. and the others o.5ooo in., with a mean diameter of o.226o in. in the former and o.25oo in. in the later ones, on a standard Io,ooo-lb. Riehl6 testing machine. From the results of these investigations it appears that: I. The length of copper crushed cylinders decreases consider-
'" Technologic Paper No. 185.