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Temperature Influence on Mechanical Properties
Similar to other metallic materials, the properties of aluminum alloys are dependent upon the temperature to which the alloy is exposed, and the cumulative amount of time exposed to that elevated temperature. Under low temperature conditions, aluminum drill pipe actually gains strength and toughness. At elevated temperatures, a permanent loss of strength can occur, depending on the length of time at the exposure temperature.
As a result, extended use of drill pipe at temperatures above 250ºF to 300ºF should be avoided in order to prevent a permanent loss in properties. However, no failures of aluminum drill pipe resulting from exposure to low or elevated temperatures have been reported.
| Temperature | Temperature | Time at Temp | % Room Temperature Property at Elevated Temperature | % Room Temperature Property at Elevated Temperature | % Room Temperature Property at Elevated Temperature | % Room Temperature Property after Exposure to Elevated Temperature |
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| Fahrenheit | Celsius | (hr) | Tensile | Yield | Elong(4D)* | Tensile | | -320 | -196 | 0 | 122% | 122% | 110% | – | | -112 | -80 | 0 | 105 % | 106 % | 100 % | – | | -18 | -28 | 0 | 103 % | 101 % | 100 % | – | | 212 | 100 | 10 | 87% | 90% | 140 % | 100 % | | 212 | 100 | 100 | 87 % | 90 % | 140 % | 100 % | | 212 | 100 | 10,000 | 86 % | 88 % | 150 % | 99 % | | 300 | 149 | 10 | 75 % | 77 % | 160 % | 92 % | | 300 | 149 | 100 | 74 % | 75 % | 160 % | 92 % |
Reference:
Kaufman, J.G., “Properties of Aluminum Alloys: Tensile, Creep, and Fatigue Data at High and Low Temperatures,” The Aluminum Association, Inc., and ASM International, pg. 29, 1999
*Elongation determined over gauge length equal to four times the pipe diameter.
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