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Alloys tested for LNG tankers
fCMGENIC]
Inews]
been evaluated at Alcoa to determine maximum allowable design stresses for the ASME Boiler and Pressure Vessel Code. Maximum allowable design stresses were found to be welded structures as for parent metal of the same thickness. Results of another investigation at Alcoa of the properties of 5083-0 aluminium alloy as thick plate indicated that, because of the very high toughness of this alloy, valid fracturetoughness (KIt)data could not be obtained on specimens up to 7 in (178 mm) thick at 77 K (both plate and weld metal). Furthermore, results of fatigue crack-growth-rate tests indicated that if a flaw about 2.5 in (63 mm) long should occur in one of the most critical locations, the flaw growth during a six month period of ship spectrum loading would be very slight.
High purity nitrogen plant designed and constructed by Petrocarbon Developmentsfor South African Nylon Spinners essential part of their fibre production. ICI, like many other major fibre producers, have found that production of their own nitrogen in a Petrocarbon nitrogen plant is cheaper than buying supplies from a gas distributor.
on skids, and pre-testing the plant under workshop conditions prior to despatch. The nitrogen plant uses a low pressure air fractionation cycle developed some seventeen years ago and which has proved its reliability on many sites throughout the world. (Petrocarbon Developments Ltd, Sharston Road, Manchester M22 4TD, UK)
The plant was installed in Cape Town and the erection on site was cut to the very minimum by assembling, mounting
Research news Alloys tested for LNG tankers At a recent ASTM symposium on the properties of materials for liquefied natural gas tankers, the primary emphasis was on development of design properties of 5083-0 aluminium alloy (parent metal plate and welds) and on
CRYOGENICS. MARCH 1977
the nickel containing steels, particularly the 9 Ni grade for service at temperatures to 77 K. Cryogenic tensile-property data from more than 300 specimens of 5083-0 aluminium alloy sheet and plate have
Fatigue crack-growth-rate studies carried out at Kaiser on specimens of 5083-0 plate at room temperature and 77 K were reported. Compact specimens 1 and 2 in (25 and 50 mm) thick were produced from 7.75 in (197 mm) thick plate for this programme. Crack growth was measured with twenty strand propagation gauges applied to the sides of the specimens in the path of the cracks and by an ultrasonic method at 297 and 77 K. In the lowstress-intensity range, crack growth rates are lower at 77 K than at 297 K. Other studies have shown that fatigue crack-growth rates are greater in the S-T orientation than for other orientations in corresponding specimens. Fatigue crack-growth-rate data obtained specimens of 9 Ni steel at the Cryogenics Division of the National Bureau of Standards indicate that the crack-growth rates are greater at 77 K. Elastic properties of 5083 aluminium alloy and four nickel alloy steels determined in the cryogenic range by means of an ultrasonic pulse-superposition method at the Institute of Basic Standards, were also presented.
189
ewst These nickel alloy steels all represent low carbon grades that can be considered for the low temperation applications. According to the normal trend, the modulus values increase as the testing temperature is decreased and then tends to level off near 0 K. (These papers are available from the American Society for Testing and Materials, ASTM STP 579, Philadelphia, Pa, USA)
Long-term experiments in space Scientists will soon be able to carry out prolonged experiments in space using NASA's LDEF (the long duration exposure facility). LDEF is a large passive unmanned structure on which over seventy separate self-contained experimental packages will be mounted. It will be carried into space by the space shuttle system, left to orbit the earth for a number of months, then retrieved, brought back to earth and the experiments returned to their owners for analysis. LDEF offers prolonged exposure to the conditions at its 300 n mi orbital altitude: weightlessness, extreme vacuum, high particle, and radiation fluxes, and also returns materials and instruments at the end of the mission. The Universities Space Research Association (USRA) has been allocated
the task of seeking worthwhile experiments for LDEF in all fields of science and technology, particularly from academic scientists. NASA will provide preflight acceptance testing, orbital flight and return for experiments endorsed by USRA. Experimenters will need to secure research funding USRA will assist in this, and in all phases of experiment development and management, where necessary. [For further details contact Dr M.H. Davis, USRA, PO Box 3006, Boulder, CO 80307, USA]
Japanese develop manganesechromium steels for low temperatures A study has been conducted at the Nippon Steel Corporation to develop austenitic manganese-chromium steels with good toughness and low thermal expansion in the cryogenic temperature range. Alloying elements in the experimental steels were added in the following ranges in percent by weight: 5 to 35 manganese, 0 to 15 chromium, 0.05 to 1.0 nickel, 0.01 to 0.15 carbon, 0.08 to 0.15 columbium, 0.05 to 0.10 vanadium, 0.06 to 0.09 titanium, and 0.07 to 0.19 nitrogen. Ingots were hot
rolled to 0.5 in (12.5 mm) thick plates which were annealed and quenched in water. Tensile and Charpy V-notch impact specimens produced from these plates were tested at room temperature, 77 K, and for some steels at intermediate temperatures. Magnetic tests were made on the fracture of these specimens to determine the degree of martensite formation. Thermal expansion of these steels was measured in the temperature range from 77 K to room temperature. The optimum base composition for the initial series of alloys tested based on strength, toughness, and thermal expansion was 25 Mn-5Cr-1 Hi. Small additions of columbium, vanadium, titanium, and nitrogen were made to this base composition. These additions did not significantly affect the expansion coefficient which was about one half of that of type 304 stainless steel from room temperature to 77 K. The columbium, vanadium, and titanium additions reduced the austenite grain size which resulted in increased strength with a limited reduction in notch toughness, and the nitrogen addition increased the yield strength. (Review of Metals Technology, Metal Properties Council, United Engineering Center, New York, New York 10017, USA)
Reprints Reprints of all articles in this journal are available in quantities
For full details of prices and availability of reprints, please write to
The ReprintDepartment, =PC House,32 High Street, G u i l d f o r d , Surrey, E n g l a n d ,
of l O 0 o r more
190
GUl 3EW
CRYOGENICS. MARCH 1977
Inews]
been evaluated at Alcoa to determine maximum allowable design stresses for the ASME Boiler and Pressure Vessel Code. Maximum allowable design stresses were found to be welded structures as for parent metal of the same thickness. Results of another investigation at Alcoa of the properties of 5083-0 aluminium alloy as thick plate indicated that, because of the very high toughness of this alloy, valid fracturetoughness (KIt)data could not be obtained on specimens up to 7 in (178 mm) thick at 77 K (both plate and weld metal). Furthermore, results of fatigue crack-growth-rate tests indicated that if a flaw about 2.5 in (63 mm) long should occur in one of the most critical locations, the flaw growth during a six month period of ship spectrum loading would be very slight.
High purity nitrogen plant designed and constructed by Petrocarbon Developmentsfor South African Nylon Spinners essential part of their fibre production. ICI, like many other major fibre producers, have found that production of their own nitrogen in a Petrocarbon nitrogen plant is cheaper than buying supplies from a gas distributor.
on skids, and pre-testing the plant under workshop conditions prior to despatch. The nitrogen plant uses a low pressure air fractionation cycle developed some seventeen years ago and which has proved its reliability on many sites throughout the world. (Petrocarbon Developments Ltd, Sharston Road, Manchester M22 4TD, UK)
The plant was installed in Cape Town and the erection on site was cut to the very minimum by assembling, mounting
Research news Alloys tested for LNG tankers At a recent ASTM symposium on the properties of materials for liquefied natural gas tankers, the primary emphasis was on development of design properties of 5083-0 aluminium alloy (parent metal plate and welds) and on
CRYOGENICS. MARCH 1977
the nickel containing steels, particularly the 9 Ni grade for service at temperatures to 77 K. Cryogenic tensile-property data from more than 300 specimens of 5083-0 aluminium alloy sheet and plate have
Fatigue crack-growth-rate studies carried out at Kaiser on specimens of 5083-0 plate at room temperature and 77 K were reported. Compact specimens 1 and 2 in (25 and 50 mm) thick were produced from 7.75 in (197 mm) thick plate for this programme. Crack growth was measured with twenty strand propagation gauges applied to the sides of the specimens in the path of the cracks and by an ultrasonic method at 297 and 77 K. In the lowstress-intensity range, crack growth rates are lower at 77 K than at 297 K. Other studies have shown that fatigue crack-growth rates are greater in the S-T orientation than for other orientations in corresponding specimens. Fatigue crack-growth-rate data obtained specimens of 9 Ni steel at the Cryogenics Division of the National Bureau of Standards indicate that the crack-growth rates are greater at 77 K. Elastic properties of 5083 aluminium alloy and four nickel alloy steels determined in the cryogenic range by means of an ultrasonic pulse-superposition method at the Institute of Basic Standards, were also presented.
189
ewst These nickel alloy steels all represent low carbon grades that can be considered for the low temperation applications. According to the normal trend, the modulus values increase as the testing temperature is decreased and then tends to level off near 0 K. (These papers are available from the American Society for Testing and Materials, ASTM STP 579, Philadelphia, Pa, USA)
Long-term experiments in space Scientists will soon be able to carry out prolonged experiments in space using NASA's LDEF (the long duration exposure facility). LDEF is a large passive unmanned structure on which over seventy separate self-contained experimental packages will be mounted. It will be carried into space by the space shuttle system, left to orbit the earth for a number of months, then retrieved, brought back to earth and the experiments returned to their owners for analysis. LDEF offers prolonged exposure to the conditions at its 300 n mi orbital altitude: weightlessness, extreme vacuum, high particle, and radiation fluxes, and also returns materials and instruments at the end of the mission. The Universities Space Research Association (USRA) has been allocated
the task of seeking worthwhile experiments for LDEF in all fields of science and technology, particularly from academic scientists. NASA will provide preflight acceptance testing, orbital flight and return for experiments endorsed by USRA. Experimenters will need to secure research funding USRA will assist in this, and in all phases of experiment development and management, where necessary. [For further details contact Dr M.H. Davis, USRA, PO Box 3006, Boulder, CO 80307, USA]
Japanese develop manganesechromium steels for low temperatures A study has been conducted at the Nippon Steel Corporation to develop austenitic manganese-chromium steels with good toughness and low thermal expansion in the cryogenic temperature range. Alloying elements in the experimental steels were added in the following ranges in percent by weight: 5 to 35 manganese, 0 to 15 chromium, 0.05 to 1.0 nickel, 0.01 to 0.15 carbon, 0.08 to 0.15 columbium, 0.05 to 0.10 vanadium, 0.06 to 0.09 titanium, and 0.07 to 0.19 nitrogen. Ingots were hot
rolled to 0.5 in (12.5 mm) thick plates which were annealed and quenched in water. Tensile and Charpy V-notch impact specimens produced from these plates were tested at room temperature, 77 K, and for some steels at intermediate temperatures. Magnetic tests were made on the fracture of these specimens to determine the degree of martensite formation. Thermal expansion of these steels was measured in the temperature range from 77 K to room temperature. The optimum base composition for the initial series of alloys tested based on strength, toughness, and thermal expansion was 25 Mn-5Cr-1 Hi. Small additions of columbium, vanadium, titanium, and nitrogen were made to this base composition. These additions did not significantly affect the expansion coefficient which was about one half of that of type 304 stainless steel from room temperature to 77 K. The columbium, vanadium, and titanium additions reduced the austenite grain size which resulted in increased strength with a limited reduction in notch toughness, and the nitrogen addition increased the yield strength. (Review of Metals Technology, Metal Properties Council, United Engineering Center, New York, New York 10017, USA)
Reprints Reprints of all articles in this journal are available in quantities
For full details of prices and availability of reprints, please write to
The ReprintDepartment, =PC House,32 High Street, G u i l d f o r d , Surrey, E n g l a n d ,
of l O 0 o r more
190
GUl 3EW
CRYOGENICS. MARCH 1977