Notes on the ASME code for design stresses for pressure vessel materials
References: wrought alloy data
Notes on the ASME code for design stresses for pressure vessel materials
The ASME code requires that the lowest of the following values be used as the design stress:-
1. 1/4 of the tensile strength, reduced to the minimum. *
2. 2/3 of the yield strength (proof stress ) reduced to the minimum. **
3. The stress to give a secondary creep rate of 0.1% in 10,000h.
4 The stress to cause rupture in 100,000h
Because of the large factor on tensile strength, (1) above, there is little incentive to use alloys with a high yield (or proof) strength. Also, secondary creep rate is a transient value and cannot easily be related to the total amount of deformation or the possibility of failure. Thus, many engineers now prefer to place less emphasis on tensile strength and to consider time to a particular deformation under load rather than creep rate. For example, the design stresses quoted in BS 1515 were based on the lowest of the following:-
5. 1/2.35 x room temperature tensile strength.
6. 2/3 of the 0.2% proof stress at temperature.
7. Stress to cause 1% creep in 100,000h.
8. 2/3 stress to cause rupture in 100,000h.
* The actual result at the appropriate test temperature is adjusted by multiplying by the factor:
Minimum expected or specified tensile or yield strength at room temperature
Actual room temperature tensile or yield strength for the material under test
** The 0.2% proof stress was used as a measure of 'yield strength' in deriving design stresses for aluminium alloys (J.E. Bowers and R.D.S. Lushey J.Inst. Met., 1972, 100,(257 - 267).
References: wrought alloy data
1. F. G. Parker, R.M. Winter and J. A. LaPorta, Proc. ASTM 1959 59 230 - 261
2. CIDEC Data Sheets
3. R. P. Reed and R. P. Mikesell, Low Temperature Mechanical Properties of Copper and Selected Copper Alloys: A compliation from the literature: NBS monograph 101, (1967). U.S. Dept. of Commerce, Boulder, Colorado, U.S.A.
4. R. I. Jaffee and R. H. Ramsey, Metal Progress 1948 54 57 - 63
5. E. Voce, Metallurgia 1946 35 3 - 9
6. A. Leogranda, W. Jung-Konig and P. Wincierz, Metal 1967 21 102 - 113
7. C. Upthegrove and H. L. Burghoff, Elevated Temperature Properties of Copper and Copper Base Alloys; ASTM Sp. Tech. Publn. no. 181 (1956)
8. D. Ashbolt and J. E. Bowers, BNFMRA Research Report A1550 July 1965
9. Alloy Digest Data Sheets
10. A. R. Pels,. Wire and Wire Products 1962 37 1398
11. J. H. Bearham and R. J. Parker, Metallurgia 1968 78 9 - 14
12. J. P. Dennison, J. Inst. Metals 1957-58 86 179 - 181
13. J. J. Carter, A. D. Michael and J. McKeown BNFMRA Research Report A.972 Dec 1952
14. J. McKeown, D. N. Mends, E. S. Bale and A. D. Michael J. Inst. Metals 1954-55 83 69 - 79
15. A.R. Anderson, E. F. Swan and E. W. Palmer, Proc. ASTM 1946 46 678 - 692
16. K. Dies and W. Jung-Konig, Metall 1960 14 1085 - 1093
17. Private communication from McKechnie Metals Limited.
1. D. Arnaud, Fonderie 1966 249 431 - 457
2. H. Waterhouse, Tensile and Impact Properties of Die Casting Alloys at Various Temperatures. Ministry of Supply, London, ASTIA Report AD159071. (1958)
3. R. Thomson Modern Castings 1968 53 (4) 189 - 192
4. R. P. Reed and R. P. Mikesell, Journal of Materials 1967 2 (2) 370 - 392
5. C. Upthegrove and H. L. Burghoff, Elevated Temperature Properties of Coppers and Copper Base Alloys. ASTN Sp. Tech.Publ. no. 181 (1956)
6. D. Arnaud, The Elevated Temperature Properties of Cast Copper Alloys. Final Report INCRA Project no. 182 Apr. 1972
7. R. D. S.Lushey and J. E. Bowers, BNFMRA Research Report A 1610 October 1966
8. W. Plageman, Fonderie 1976 357 242 - 243
9. Private Communicatior from Lips B. V. Holland
10. R. P. Reed and R. P. Mikesell Low Temperature Mechanical Properties of Copper and Selected Copper Alloys. A compliation from the literature. NBS monograph 101: (1967) U.S. Dept. of Commerce, Boulder, Colorado, U.S.A.