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Low Temperature
Service - LT Series
These Proprietary Grades are designed to be used under low temperatures
- Arctic regions included -, with improved fracture toughness.
Steel Grades Properties
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Steel Grade
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Yield Strength
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Minimun Tensile
Strength
|
Elongation
(% in 2")
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MIN. CVN Required for
CL Full Size specimen10X10 mm at -45°C*
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Ksi (Mpa)
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Ksi (Mpa)
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Min. Individual
(Joules)
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Min. Average
(Joules)
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TN 55 LT
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55-90 (379-621)
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95 (655)
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According to
API Formula |
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TN 80LT
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80-110 (551-758)
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100 (689)
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TN 95 LT
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95-110 (655-758)
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105
(753)
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TN 110 LT
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110-140 (758-965)
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125
(861)
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TN 125 LT
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125-150 (861-1035)
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135 (931)
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Maximum
Through-Wall Hardness Variation [HRc]
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Wt ≤0.5"
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0.5" < wt <0.75"
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0.75" ≤ wt <1.0"
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Wt ≥ 1"
|
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3
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4
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5
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6
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*Lower test temperature available by agreement
Tenaris´ Low temperature series have been designed to cope with
arctic environments and permafrost problems. These specialised products
have yield strengths ranging from 55.000 to 125.000 psi. In frigid zones
- due to cold embrittlement - high notch toughness at low temperature
for casing and tubing is required in order to withstand shock during
handling - storage, makeup and running-.
The susceptibility to cold embrittlement is increased through increased
yield strength. Even so, Tenaris has developed Low Temperature Grades
that guarantee both good toughness at low temperature and high yield
strength.
Like most mechanical properties, the toughness of steel can usually
be traced back directly to its microestructure. Steels having a tempered
martensitic structure offer an optimum balance of strength and low-temperate
toughness. Therefore, the optimum route towards high strength grades
- whilst maintaining good low-temperate toughness - is obtained by a
highly tempered martensitic microstructure.
Field of application Guidelines
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9 5/8 47#TN 110LT
Full Ductile fracture is observed
on the fracture surface After CVN testing at -46°C. SEM, 400X.
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