used in the autoclave. Actual service conditions are much less severe in that the full load is not applied until the vessel has reached about 500’ F.
7.
100..
50
90 ..
45
80 ..
40
70
-.
60 -. W
2
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literature Cited
35
(1) Cottrell, A. H., in “Theoretical Aspects
of Fracture,” Felbeck Averbach and Thomas Hahn, eds., pp. 20-53, Technology, Cambridge, Mass., and Wiley, New York, 1957. (2) Mott, N. F., in “Theories of Fracture in Metals,” R. Grammel, ed., pp. 53-9, Springer, Berlin, 1956. (3) Parker, E. R., “Brittle Behavior of Engineering Structure,” p. 64, Wiley, New York, 1957. 16 id.,p. 108. 5) Saibel, Edward, IND.ENG. CHEM.53, No. 7, 56A (1961).
30
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20
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10
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0
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RECEIVED for review April 24, 1961 ACCEPTEDSeptember 19, 1961
72O
150. ZOOo
3000
I t does seem probable, however, that a combination of unfavorable circumstances had occurred: the presence of a notch and a temperature below the notch transition. Redesigned Vessel. T h e properties of the steel were then changed by the appropriate heat treatment to bring about a more ductile behavior. These properties are given in Table I. The design was also modified by the removal of the shoulder. The removal of the shoulder may have helped increase ductility, so unfortunately there is not a clear cut answer to what factor or factors improved the design. Ordinarily, it would be thought that this would have a weakening effect, as the removal would raise the nominal (average)
978
500°
4000
600°
700°
800.
stress. However, this may not be the case at all, again emphasizing the importance of local rather than average conditions in the consideration of fracture. The test was carried out again at room temperature, and the pressure was raised to 45,000 p s i . This produced a tangential stress in the wall of about 67,200 p s i . , by LamC’s formula. The test was successful. The increased ductility enabling a relief of stress through plastic flow undoubtedly brought about the improvement. Although increased ductility could have been obtained also by increasing the percentage of nickel, it could not be done in this manner in this particular instance because the nickel reacted with the product to be
INDUSTRIAL AND ENGINEERING CHEMISTRY
Division of Industrial and Engineering Chemistry, 139th Meeting, ACS, St. Louis, Mo., March 1961.
Correction
A Rapid Method for Obtaining Vapor-Liquid Equilibrium Data -Theoretical Aspects In the blurb of this article by R. S. Ramalho, F. M. Tiller, W. J. James, and D. W. Bunch [IND.ENG.CHEM.53, 895 (1961)], the first checked statement, “The experimenter can obtain three points per hour,” is incorrect. I t should read “The entire vapor liquid curve may be obtained in a single experiment lasting 2 or 3 hours.’’ In some cases, more than 50 points were obtained in this period of time.
